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RSA-576 Factored

An anonymous reader writes "I thought Slashdot would have picked this up several days ago, but apparently not. Although you still won't see any mention of it on the RSA challenge site, Mathworld is carrying the news that a team at the German Bundesamt fur Sicherheit in der Informationstechnik submitted a factorization of RSA-576 on December 3. RSA-576 is the smallest challenge number that RSA Security offers a cash prize for, to the tune of $10,000"

205 of 321 comments (clear)

  1. I think my form of encryption is better by Wigfield · · Score: 3, Funny

    Ontday oyay inkthay osay?

    1. Re:I think my form of encryption is better by cgranade · · Score: 4, Insightful

      I don't know... maybe...
      u sib;r jbiq (shifted all the keys to the left.)

      Seriously, though, all of these ciphers can be broken. It's just a task of minimizing the value to the cracker by making it take as long as possible to get the data, under the thought that it just won't be worth the time.

      --

      #define DRM chmod 000

    2. Re:I think my form of encryption is better by Snoopy77 · · Score: 1
      Ontday oyay inkthay osay?

      otgay otay dmitaay tiay siay rettypay oodgay.

      --
      "She's a West Texas girl, just like me" - G.W Bush Iraqis
    3. Re:I think my form of encryption is better by LeninZhiv · · Score: 1

      V guvax gurer fubhyq or n fynfuqbg frpgvba jurer nyy cbfgf unir gb or va EBG13.
      Guvf fvgr qbrfa'g yrg zr jnfgr rabhtu gvzr nf vg vf!

      And while we're on this kind of thing, does anyone know what the point of the UNIX command "rev" is? (as in "$ echo This is pointless | rev" -> sseltniop si sihT)? Why on earth does that come installed on Debian, and does every distro and UNIX variant use it?

    4. Re:I think my form of encryption is better by Anonymous Coward · · Score: 5, Funny

      it's so you can read the screen when you look at it over your shoulder with a mirror.

    5. Re:I think my form of encryption is better by the_argent · · Score: 5, Funny

      Or my personal favorite....

      Double ROT13.

      Which incidently, is hereby covered under the DMCA, if you manage to decipher it will be fully procecutable under the fullest extent of the law.

    6. Re:I think my form of encryption is better by wurp · · Score: 4, Insightful

      Sure, all codes (except one time pads and equivalents) can be broken. The difference is whether it takes a day to crack the code or it can be proven that it requires either a centuries-sought breakthrough in mathematics or all the computers in the world working for ten thousand years.

      I don't know how you feel about it, but quantitative differences on those scales qualify as qualitative differences to me. Your 2048 bit PGP key simply isn't crackable by any reasonable standard. The reason people succeed at these challenges is because the bar has been set intentionally low.

    7. Re:I think my form of encryption is better by hank · · Score: 5, Informative

      They also set the bar at your "reasonable standard" - the factorization of a 2048-bit number brings in $200,000 USD.

      http://www.rsasecurity.com/rsalabs/challenges/fa ct oring/numbers.html

    8. Re:I think my form of encryption is better by Anonymous Coward · · Score: 1

      Why can't one-time pads be cracked? I think I read somewhere that OTPs are as large as the data being sent with it, but still wouldn't that be crackable given an infinite number of monkeys?

      The three of us slashdot regulars who aren't cryptographers are confused by most of this, and the site being slashdotted doesn't help either.

    9. Re:I think my form of encryption is better by Zork+the+Almighty · · Score: 2, Informative

      A one-time-pad ciphertext of length n decodes to all 2^n possible messages with equal probability. This situation can not occur if the message being encrypted is larger than the key being used.

      --

      In Soviet America the banks rob you!
    10. Re:I think my form of encryption is better by LnxAddct · · Score: 5, Informative

      No because if you take a xor b where b is your message and a is the key then if all the person had was c (the output) then inorder to find b, they would have to xor it with every possible value of a. This would result in every possible combination of bits(do it on paper and you'll see). So the cracker would be left with a list of every possible way of representing a 2048(just an example) bit number essentially going from 0 to 2^2048. Convert this to ascii and you've got every possible combination of characters that can fit in 2048 bits. That means that any sentence that can be written in 2048 bits would appear in the cracker's lsit and therefore there would be too many logical outcomes and noway too tell which is right.i.e. you could have "The ships will attack on the east coast", "The ships will attack on the west coast", "The plane will attack on the west coast", "We made coffee for the Germans." ... or literally every posible combination.

    11. Re:I think my form of encryption is better by AnotherBlackHat · · Score: 2, Informative

      Sort by extension;
      ls -l | rev | sort | rev

      Sort by domain;
      rev address_list | sort | rev

    12. Re:I think my form of encryption is better by HuguesT · · Score: 5, Informative

      OTP can't be cracked even with brute force, because there is no pattern in the encrypted result and each letter is coded independently of all the others.

      To give you an example, think of a one-word message:

      'GO' (= 0x47 Ox4F)

      Here is a two-byte one-time pad:

      Ox5E9C

      Here is the result of the encryption:

      0x474f xor 0x5E9H = 0x19d3

      Now the OTP gives you back the unencrypted text if you have it:

      0x19d3 xor 0x5E9C = 0x474f = 'GO'

      Now, if you don't know the OTP and all you have is the encrypted text, then your only recourse is to try all the possibles OTPs with brute force. The problem is that amongst all the results, you will indeed have 'GO', but also 'NO', 'IT', '42', etc. All the possible two-letter words will be there, and there will be no way to find out which is the correct one.

      This result trivially extends to messages of any length. Using brute force with OTPs only generates all the possible messages of a given lengths, giving no clue as to which is the correct one.

    13. Re:I think my form of encryption is better by Anonymous Coward · · Score: 2, Funny

      ROT 104 baby, it's FOUR times safer than yours....

    14. Re:I think my form of encryption is better by tuxfan · · Score: 1
      You may be surprised at how ineffective that first one is:
      $ ls -1 | rev | sort | rev
      i.mp3
      sex.c
      a.tiff
      girl.jpg
      had.pl
      never .iso
      with.s
      have.txt
    15. Re:I think my form of encryption is better by spectral · · Score: 2, Informative

      that'd certainly group by extension/domain, but not sort (At least, not the way people usually want things sorted)

      address_list:
      microsoft.com
      slashdot.org
      bing hamton.edu
      somethingpositive.net

      reverse:
      moc.tfosorcim
      gro.todhsals
      ude.notma hgnib
      ten.evitisopgnihtemos

      sort:
      gro.todhsals
      moc.tfosorcim
      ten.evitisop gnihtemos
      ude.notmahgnib

      reverse:
      slashdot.org
      microsoft.com
      something positive.net
      binghamton.edu

      a proper sort (not group) by domain/extension would be (ascending):
      microsoft.com
      binghamton.edu
      somet hingpositive.net
      slashdot.org

      it's useful, but your examples need work.

    16. Re:I think my form of encryption is better by mystran · · Score: 4, Informative
      For people that think they are now going to generalize this into some kind of general purpose encryption scheme, I'd like to add that OTP works ONLY when it's "one time" pad. That is, once you try to reuse any or all of the pad in any way, you lose the property of uncrackability and it becomes a statistical problem to solve the message.

      In plain english, this means that OTP must be unique and truly random and have the same length as the message. While the encryption is uncrackable, the problem of transmitting proper OTPs remains.

      Not to say that it couldn't be useful for some special cases, but for general purpose encryption, no.

      --
      Software should be free as in speech, but if we also get some free beer, all the better.
    17. Re:I think my form of encryption is better by NonSequor · · Score: 5, Informative

      The problem of course is that you can't reuse one-time pads (thus the name) otherwise they are subject to certain attacks. So basically, if you deliver a one-time pad to someone, you are using some sort of secure delivery at one point in time to guarantee the ability to send a secure message at some time in the future.

      However, quantum cryptography may be able to render the problems of delivering one-time pads obsolete (well, at least for applications where you can get a fiber link between two points or where you have a line-of-sight with the other party). Quantum cryptography is really just a means of giving Alice and Bob the same random string along with a method of detecting eavesdropping (basically, it won't work if someone eavesdrops).

      But I don't believe in any of this quantum voodoo. I'm working on the ultimate in security. Curses. Just put a curse on your message so that it kills anyone other than its intended recipient and you can be as insecure in the transmission as you like. Remember, dead men tell no tales.

      Man, have I really been rambling on for this long? Sorry, I've been drinking a bit.

      --
      My only political goal is to see to it that no political party achieves its goals.
    18. Re:I think my form of encryption is better by Qrlx · · Score: 1

      Wouldn't it work pretty well to establish a pre-determined OTP generator? like, the winning lottery numbers last night, the answer to 1 across and 3 down from yesterdays' crossword puzzle, and the third word from each story on the front page. Oh and the cards in East's hands from the bridge game. All information to be obtained from the daily newspaper.

      You'd have a new OTP every day, and if your generating algorithm were sufficiently weird it would be essentially unbreakable, would it not? Provided of course that the communicators go to some length to not make it obvious that's why they buy the paper each morning.

      Or what about something like SecurID, just use some funky algorigthm to generate new OTPs every sixty seconds. Every once in a while, twiddle the formula.

    19. Re:I think my form of encryption is better by Goldfinger7400 · · Score: 2, Funny
      Wouldn't it work pretty well to establish a pre-determined OTP generator? like, the winning lottery numbers last night

      Yeah, but then the NSA would figure out how to systematically win the lottery every time in an effort to break the one time pad!

    20. Re:I think my form of encryption is better by putaro · · Score: 5, Informative

      Congratulations - you've invented symmetric key cryptography! Looked at from a far enough distance, any symmetric key crypto algorithm is basically a pseudo-random number generator that combines the pseudo-random number stream with the plaintext and the key is the seed to the random number generator.

    21. Re:I think my form of encryption is better by Fred+Ferrigno · · Score: 1

      Wouldn't it work pretty well to establish a pre-determined OTP generator? like, the winning lottery numbers last night, the answer to 1 across and 3 down from yesterdays' crossword puzzle, and the third word from each story on the front page. Oh and the cards in East's hands from the bridge game. All information to be obtained from the daily newspaper.

      In any of these cases, if a third party discovered your scheme, it's worthless. In general, that's called security by obscurity, merely hoping the other side doesn't figure it out. People can be bribed, patterns can be recognized, and having a OTP that's an English sentence makes cracking your message several dozen orders of magnitude easier.

      A OTP has to be completely random. Otherwise it's worthless. The Germans did basically what you propose during WWII, and yeah it did work for a while. But then some really smart people got at it, did the statistical analysis, recognized the patterns and broke it. With today's computers it'd be just that much easier.

      That's why encryption schemes like RSA are so useful. It doesn't matter if the other side knows exactly how the encryption works; it doesn't matter if they know everything you know about the message; if they don't have the key, you can mathematically prove that you'll be long dead before they can break it.

    22. Re:I think my form of encryption is better by JuggleGeek · · Score: 1
      Double ROT13.

      That was, quite possibly, the first highly modded "funny" post that I've ever seen on /. which was actually funny, and it's even on-topic! Pbatenghyngvbaf.

    23. Re:I think my form of encryption is better by hugesmile · · Score: 2, Insightful
      It's just a task of minimizing the value to the cracker by making it take as long as possible to get the data, under the thought that it just won't be worth the time.

      Why do people always assume that code-breakers will be White Guys?

    24. Re:I think my form of encryption is better by *weasel · · Score: 1

      what you are referring to as quantum cryptography isn't really cryptography, it's a semi-convenient side effect of encoding messages at the quantum level. Physics guarantees that the first reader of such a message necessarily destroys the message. Trick is, you still need decent cryptography behind such a scheme, as it won't much matter to a cracker if you know he's there or not -- he'll still have your sensitive info if you didn't properly encrypt the actual message. in most applications you simply can't stop communicating and still remain relevant just because you know someone is eavesdropping.

      convenient because you know for certain if you're being spied on? sure.
      secure? hell no.

      case in point: the US -knew- the japanese were spying on our wwII transmissions. just as the Japanese -knew- the US was spying. knowing that the enemy is listening didn't alleviate the problem - it still comes down to good crypto. one can't simply stop communicating and wait for the eavesdropper to leave.

      truly secure quantum communication:

      1. achieve quantum-entanglement of 2 particles
      2. build com device to send messages via altering spin of one particle
      3. give the second particle to your friend
      4. build com device to read messages via observing the spin of the second particle
      5. enjoy instant snoop-proof communications ...
      6. profit?

      (truly secure because there is no traditional transmission. still theoretcial of course ;p -- and it's one-way, you'd need a second pair of entangled particles to transmit back. but that second unit would be trivial if you could actually create the first functional unit.)

      --
      // "Can't clowns and pirates just -try- to get along?"
    25. Re:I think my form of encryption is better by WhiteDragon · · Score: 1
      I think you're thinking of tac, that reverses it's input by lines instead of a line at a time. Eg.
      echo -e hello\\nthere | tac yields:
      there
      hello

      --
      Did you mount a military-grade, variable-focus MASER on an unlicensed artificial intelligence?
    26. Re:I think my form of encryption is better by Steve+B · · Score: 1
      Trick is, you still need decent cryptography behind such a scheme, as it won't much matter to a cracker if you know he's there or not -- he'll still have your sensitive info if you didn't properly encrypt the actual message.

      The way around this is to send a one-time pad over the quantum link, and to echo it back. That guarantees that there was no interception in the middle (the only remaining hole to plug is to confirm that an interloper hasn't completely replaced your intended correspondent at the other end of the line).

      --
      /. If the government wants us to respect the law, it should set a better example.
    27. Re:I think my form of encryption is better by Lehk228 · · Score: 1

      if you make the encryption rotate around itself (modulus 27 would be enough to encode letters and spaces) and determine whether to add or subtract each letter based on the starting letter and the previous encoded letter with the arraingement of letters in the encoded file moved using a second pad it would make decrypting it immensly difficult because there would no longer be a means of determining characters by their usage frequency, especially if the message is surrounded/ infiltrated with junk random values that would be impossible for a, algorythm to determine with any better probability than random what a message said, especially if the random junk was written to weight itself towards certain values each message

      --
      Snowden and Manning are heroes.
    28. Re:I think my form of encryption is better by Theaetetus · · Score: 2, Funny
      Double ROT13.

      As a really amusing side note, BBEdit, by Bare Bones Software, a really great programmer's tool for the Mac, has a ROT13 tool...

      When you select text and use the tool, a warning pops up on the screen:

      "Warning: This operation is not undoable."

      -T

    29. Re:I think my form of encryption is better by B3ryllium · · Score: 1

      I do believe it would be "every possible permutation", not "combination". In a permutation, the order of things is important - this means that there are actually an even larger number of possibilities.

      Like, lets say you have five letters, ABCDE. In a combination, the order is irrelevant, and so it doesn't matter how you arrange them.

      In a permutation, order is highly important. For five letters, the number of possible permutations is 5! (factorial). This means there are 120 possible ways to arrange those five letters. (Try it: 1x2x3x4x5). Imagine if you have 50 characters? Most calculators refuse to calculate 100Factorial.

      (I don't know if I really have a point, except to say that I think you should have used permutation instead of combination, because combination - despite the socially accepted meaning - actually makes it seem less impactful than it should be.)

      *Disclaimer: IANAS. (I am not a statistician.)

    30. Re:I think my form of encryption is better by *weasel · · Score: 1

      exactly, it all comes back to doing proper encryption. 'quantum' cryptography isn't going to change much in the security biz. it's a buzzword now, a far-off technology, and when it hits, it'll just be another flavor of the same game. it doesn't help much, it just has a convenient feature that only confirms the key assumption that all cryptographers start with.(that somebody is listening, but information needs to be exchanged)

      you still need solid cryptography, and right now, that seems to be most effectively done through one-time pad and public/private key pairs.

      --
      // "Can't clowns and pirates just -try- to get along?"
    31. Re:I think my form of encryption is better by Wavicle · · Score: 1

      It is a good thing you were paying some attention in your stats class, but... This problem is not a selection without replacement. This problem is a selection with replacement. Thus A, B, C, D or E can occur in any of the five positions with equal probability. Thus, the proper combinatorics in this case is 5^5, or in the general case b^n. For a 2048 bit message it's 2^2048.

      So to get message b from encrypted message c, you must try all possible bit patterns in a. You will get message b out of it, but you'll also get all possible messages of length |b|... One of those patterns probably contains the DeCSS source code and is therefore banned under pain of death or something.

      --
      Education is a better safeguard of liberty than a standing army.
      Edward Everett (1794 - 1865)
    32. Re:I think my form of encryption is better by DarthTaco · · Score: 1

      It doesn't matter if the other side knows exactly how the encryption works; it doesn't matter if they know everything you know about the message; if they don't have the key, you can mathematically prove that you'll be long dead before they can break it

      RSA is not mathematically proven to take a long time to hack in general. The only thing we know about it is right now we don't have a fast way cracking it. There is no proof (mathematical or otherwise) that says we won't discover something tomorrow that renders RSA of any bit length worthless.

    33. Re:I think my form of encryption is better by bolthole · · Score: 1

      you just THINK quantum entanglement is secure. But science doesnt really understand quantum entanglement, so it has no idea whether it is possible to observe methods of communication with it.

    34. Re:I think my form of encryption is better by EvilSporkMan · · Score: 1

      you can mathematically prove that you'll be long dead before they can break it.
      Unless "they" get lucky, and THEN what do you do?

      --
      -insert a witty something-
    35. Re:I think my form of encryption is better by jjgm · · Score: 1

      You'd have to be pretty far away and have bad eyesight, because that description is wrong. You've described what is called a "stream cipher", that is, an algorithm that uses a PRNG to generate a keystream. The most popular stream cipher is RC4.

      Block ciphers do *not* directly combine a random number stream with the plaintext; they encrypt the plaintext with the key via a defined algorithm. Examples of block ciphers are DES and AES.

      Now, it's true that the output of a block cipher can be constantly re-encrypted, thus generating a series of pseudo-random numbers suitable for XORing a plaintext stream; however, that's just a fancy PRNG for a stream cipher! You'd be wise not to equate the two.

      As ever, Bruce Schneier's Applied Cryptography is the recommended tome to understand the difference in detail, without gloss.

      - K

    36. Re:I think my form of encryption is better by bensagenius · · Score: 1

      I for one appreciate the Douglas Adams reference.

      --
      I am not left-handed, either!
    37. Re:I think my form of encryption is better by putaro · · Score: 1

      You're correct, I should have said "many" instead of "any." Though, you could look at a block cipher as being a PRNG with the key + plaintext block as the seed.

    38. Re:I think my form of encryption is better by ross+axe · · Score: 1

      Of course, rev can be used for that as well.

    39. Re:I think my form of encryption is better by -brazil- · · Score: 1

      Nope. By craptographic standards there's probably already a known attack that easily breaks such a cipher. If not, a good cryptoanalyst could come up with one in a couple of days.

      --

      The illegal we do immediately. The unconstitutional takes a little longer.
      --Henry Kissinger

    40. Re:I think my form of encryption is better by WhiteDragon · · Score: 1
      how? I looked at the man page for rev, and I don't see any such option...
      REV(1) BSD General Commands Manual REV(1)

      NAME
      rev - reverse lines of a file

      SYNOPSIS
      rev [file]

      DESCRIPTION
      The rev utility copies the specified files to the standard output,
      reversing the order of characters in every line. If no files are speci-
      fied, the standard input is read.

      BSD March 21, 1992 BSD
      --
      Did you mount a military-grade, variable-focus MASER on an unlicensed artificial intelligence?
    41. Re:I think my form of encryption is better by ross+axe · · Score: 1

      echo -e hello\\nworld | `echo cat | rev`
      Easy

    42. Re:I think my form of encryption is better by NonSequor · · Score: 1

      Unfortunately it doesn't work that way. It's more like a quantum key exchange and all it does is guarantee that two people have the same random string of bits. You have no control over what that string is. Also, if someone does eavesdrop, you won't have the same string as the person on the other side and so you can't send anything. So basically, a man in the middle attack won't work, but you still won't be able to send anything. You're out of luck until you can send an assassin to inspect the line or something like that.

      --
      My only political goal is to see to it that no political party achieves its goals.
    43. Re:I think my form of encryption is better by WhiteDragon · · Score: 1

      nice! :-)

      --
      Did you mount a military-grade, variable-focus MASER on an unlicensed artificial intelligence?
  2. Well, that's just fantastic, isn't it by mcc · · Score: 4, Funny

    I think that composite numbers everywhere will sleep just a little bit less securely tonight, knowing that the Bundesamt fur Sicherheit in der Informationstechnik is out there, somewhere, waiting for them.

    Yup.

    1. Re:Well, that's just fantastic, isn't it by janbjurstrom · · Score: 1

      David Rees, is that you??

      (Why aren't you updating GYWO anymore? I miss it man.)

      --
      668.5
  3. Is 576bit big? by The+Real+Chrisjc · · Score: 3, Interesting

    Wow, I havn't really read in to it, but is that very big? I mean, they were talking about not too long ago that 128bit encryption is "almost impossiable" to break. If this is 576bit encryption, and they've broken it, doesn't this mean that 1024bit is looking slightly weak? Whats the 'difficulty' of breaking this key on a relative scale?

    Chris

    1. Re:Is 576bit big? by cgranade · · Score: 4, Interesting

      It should go up exponentially, so that 1024 is much more than twice as hard. However, with Beowulf clusters and the new primability test, this is being offset quickly.

      --

      #define DRM chmod 000

    2. Re:Is 576bit big? by Sage+Gaspar · · Score: 4, Informative

      Well, there is no uncrackable code. The idea is to make it as hard as possible. For each message transmitted using one of those keys, a potential codebreaker would have to dedicate however much time this team of professional scientists on powerful computers would take.

      As technology gets better, the level of encryption gets better with it. It's a constant battle. Of course, you're not going to want to make RSA your sole method of encryption and post the key all over the web if you're working on ridiculously top-secret government projects, but then again, you wouldn't want to rely solely on any type of encryption and you wouldn't be transmitting it openly over the Internet.

    3. Re:Is 576bit big? by Ageless · · Score: 5, Interesting

      When people talk about 128 bit encryption being hard to break they are talking about symmetric algorithms such as Blowfish. A 128 bit symmetric algorithm is still very, very tough to crack a key for.

      This particular challenge is for the RSA algorithm which is an asymmetric algorithm. They require much longer keys to be secure. Right now most people recommend at least a 2048 bit key for RSA and plenty of people are using 4096 bit keys.

      Comparativly, it should be a long, long time before anyone is worried about their current keys. Back in the day when PGP came out, it was fairly common for people to use a 512 bit key with RSA, but most used 1024. Those people could be concerned at this point that their old messages could be cracked.

    4. Re:Is 576bit big? by Anonymous Coward · · Score: 1, Insightful

      When you refer to 128 bit, that gerearlly is symmetric key Encryption (as in session key), and yes its still very hard to break via brute force.

      When you refer to 1024 bit, this is generally asymmetric (as in public/privite key)

      Two very different scales. I assume the 576bit is also refering to the latter which means the key is about half as long as the current standard.

      Note that half the key length does NOT mean half as hard - think binary

      sorry for any spelling errors;-)

    5. Re:Is 576bit big? by mattjb0010 · · Score: 3, Insightful

      Well, there is no uncrackable code

      except for a correctly used one-time pad.

    6. Re:Is 576bit big? by damiam · · Score: 3, Informative
      No. RSA encryption, and public-key encryption in general, uses significantly higher keysizes to attain the same security as private-key cryptosystems at lower keysizes. The difference is that, in a public-key cryptosystem, two parties can talk securely without already both knowing a secret key.

      128-bit private-key encryption is virtually impossible to break, because you'd have to test every single 128-bit number. 576-bit public-key encryption is much easier, because you don't have to test every possible key. In this case, RSA uses prime numbers to generate keys. You have to factor the given 576-bit composite into its prime factors, which is much easier than testing every possible 576-bit key (or even every possible 128-bit key).

      --
      It's hard to be religious when certain people are never incinerated by bolts of lightning.
    7. Re:Is 576bit big? by Stephan+Schulz · · Score: 4, Informative
      Wow, I havn't really read in to it, but is that very big? I mean, they were talking about not too long ago that 128bit encryption is "almost impossiable" to break. If this is 576bit encryption, and they've broken it, doesn't this mean that 1024bit is looking slightly weak? Whats the 'difficulty' of breaking this key on a relative scale?
      There is a different between keys for symmetric encryption algorithms like DES, 3DES, Blowfish, and keys for asymmetric (public key) algorithms like RSA and Diffie-Hellman. Symmetric 128 bit keys are still considered safe. 1024 bit asymetric keys are safe for the moment - I belive for long-term security sensitive applications, 2048 bit keys are recommended nowadays. Here is a table comparing the cost of breaking (well, brute-forcing) symmetric and asymmetric cyphers for a given key lenght.

      My PGP key is still 1024 bits, and I don't break a sweat.

      --

      Stephan

    8. Re:Is 576bit big? by Fnkmaster · · Score: 4, Informative
      128-bit encryption generally refers to key size in symmetric encryption algorithms, like 3DES, IDEA, etc. These encryption methods generally are broken by brute force searching a 128-bit space of keys - that means you have to check on the order of 2^128 different keys until you know if you've found the right one (obviously, this assumes that there are no fundamental cryptographic weaknesses in the algorithm, known-plaintext attacks or other stuff like that).


      Assymmetric encryption algorithms, like RSA, rely on a hard problem with two parts needed to reconstruct the solution. In the case of RSA, those two parts are a large composite number with precisely two prime factors, and one of the prime factors (without one of the prime factors, finding out the other prime factor is deucedly difficult). Basically to "crack" RSA you have to factor the large composite number into its two prime factors. With RSA, the keysize refers to the size, in bits, of the composite and prime numbers you're working with. The thing is that you don't have to search an entire 512-bit keyspace to crack a 512-bit RSA key, you just have to try every reasonably possible _prime_ number that might be a factor of that 512-bit composite. And actually, you don't even really have to do that, since there are substantially better techniques for factoring numbers than brute force, requiring less computational effort.


      So that, my friend, is why comparing "128-bit" encryption to "512-bit" or "1024-bit" RSA or other assymmetric encryption techniques (which are similar but rely on numerical problems other than factoring large numbers) isn't terribly meaningful.

    9. Re:Is 576bit big? by Anonymous Coward · · Score: 1, Interesting

      You can't compare the key sizes of symmetric key algorithms (like DES or AES or Blowfish) with the key sizes of public key algorithms (like RSA or ElGamal). 128 bits for symmetric key algorithms is still practically impossible to break but 128 bits for RSA is now pretty easy to break. The difficulty of breaking these algorithms is thought to be exponential so adding an extra bit doubles the amount of time it takes to break the algorithm -- if this is true, then 1024 bits should still be safe (it will take 2^448 times longer than 576 bits assuming the same hardware and software).

    10. Re:Is 576bit big? by FU_Fish · · Score: 2, Interesting

      You may be comparing two different types of encryption. For block algorithms such as DES and AES, 128 bit is still fairly reasonable, however not for RSA (and other public key algorithms). Currently, 1024 bit RSA is considered reasonably secure and 576 is, as we can clearly see, quite insecure. I won't go into the details of why different algorithms need such drastically different key sizes here, but if you'd like to know more, the Crypto-FAQ is a good place to start.

    11. Re:Is 576bit big? by I+Be+Hatin' · · Score: 5, Funny
      However, with Beowulf clusters and the new primability test, this is being offset

      Woop! Woop! Woop! Bush-ism alert! Bush-ism alert!

      Perhaps you meant primality?

      --
      I know god exists. I read it on the internet, so it must be true.
    12. Re:Is 576bit big? by tang · · Score: 3, Informative

      "with a sufficiently large message,.... you can eventually reverse engineer the encryption method used."

      Nope! If your one pad key is the same size as the message you are sending, it is unbreakable. Knowing any portion of the message would not help you one bit. Except of course, that you know the part of the message that you know...but you already knew that, so it doesn't help with what you don't know...nevermind:)

    13. Re:Is 576bit big? by mattjb0010 · · Score: 1

      That depends on the message size - with a sufficiently large message, with any portion of it being known by the interceptor, you can eventually reverse engineer the encryption method used.

      Well even if they have part of the message, they still won't be able to decipher the rest of it with a one-time pad. You mention the limitations, but there are situations where those aren't problems, eg you give the other party the one-time pad in person, then communicate only a few messages at some distance.

    14. Re:Is 576bit big? by harlows_monkeys · · Score: 1
      More importantly, you still have to get the one-time pad to your compadre in the first place - and who's to stop someone intercepting it there, unless you hand it to them? (In which case, why aren't you just telling them face to face?)

      There are many situations in which you know that you will in the future need to send secure messages to someone you are meeting with now (diplomats, for example, or military units). One time pads are quite useful for this (and are in fact widely used).

    15. Re:Is 576bit big? by dirtydamo · · Score: 4, Informative

      It should go up exponentially, so that 1024 is much more than twice as hard. However, with Beowulf clusters and the new primability test, this is being offset quickly.


      For the n-th time...

      The new primality test has little practical value, because the previous testing algorithms, although probabilistic, are vastly faster in practice.

      Primality testing also has little to do with factorization algorithms.

    16. Re:Is 576bit big? by Kwil · · Score: 3, Informative

      A correctly used one-time pad can not be reverse engineered, because, if used correctly, it's creation is done in a completely true random format. Since true randomness by definition cannot be engineered, only found, then it is impossible to reverse engineer it.

      Now, to do two way communication, you'd need only two pads of sufficient size, one for encoding on each end. You would of course need a duplicate of each side's pad on the other side for decoding and passing these pads is indeed the main weakness.

      However, you can, as you say, hand it to them. The reason you might not be telling them the information to be encoded face to face is because you don't have that information yet. The beauty of one-time pads is that they never expire. Someone might find some way to factor primes instantly via quantum computing, and your one-time pad would not be affected.

      I suppose if an interceptor somehow found the source of randomness that you used, and somehow managed to find records as to what time-period/portion of it you used, they could then use that information to crack your one-time pad, essentially by recreating it.

      But in essence, a correctly created/used one time pad can be very useful, especially with high-density storage media like DVDs where you could store gigabytes of numbers for your OTP creation.

      --

      That Jesus Christ guy is getting some terrible lag... it took him 3 days to respawn! -NJ CoolBreeze

    17. Re:Is 576bit big? by Bombcar · · Score: 1

      The way a one time pad works means that if used correctly it is just as likely that a five meg message is the complete works of Shakespear as it is to be missle plans. Basically, it is like a furnace: you can hear whatever you want to hear because every sound is there.

    18. Re:Is 576bit big? by mage_naes · · Score: 3, Informative

      This represents a significant improvement on the previous factorization record. I show the following as the current top 10 hardest factorizations:

      RSA-576 2003 1881 C174=P87*P87 GNFS Bahr/Franke/Kleinjung/Montgomery/te Riele/Leclair/Leyland/Wackerworth
      RSA-160 2003 2152 C160=P80*P80 GNFS Bahr/Franke/Kleinjung/Lochter/Bohm
      2^953+1 2002 3950 C158=P73*P86 GNFS Bahr/Franke/Kleinjung
      RSA-155 1999 1094 C155=P78*P78 GNFS te Riele/CWI et al.
      Code Book 2000 1074 C155=P78*P78 GNFS Almgren/Andersson/Granlund/Ivansson/Ulfberg
      HP49( 95) 2003 2651 C153=P68*P85 GNFS Kruppa/Leyland
      HP49(97) 2003 1268 C151=P55*P96 GNFS Kruppa/Leyland
      2^1064+1 2002 5473 C143=P70*P73 GNFS Franke/Kleinjung
      92!+1 2001 1243 C143=P60*P83 GNFS Franke/Kleinjung
      2^779-1 2001 7468 C142=P57*P86 GNFS Dodson/CWI/Lenstra/Edick/Leyland

      Please note that in most cases it is a cofactor of the indicated number which
      was factored; that is, smaller factors may have been extracted using trial
      division, the elliptic curve method, etc. The third column gives the first
      four digits of the composite number.

    19. Re:Is 576bit big? by NonSequor · · Score: 1

      You can get away with much shorter key sizes using elliptic curve methods. Currently reccomended sizes are at least 80 bits for a symmetric key and 160 bits for an asymmetric key.

      --
      My only political goal is to see to it that no political party achieves its goals.
    20. Re:Is 576bit big? by Ageless · · Score: 4, Interesting

      RSA has been the defacto standard for public key exchange since it came around. PGP was based on it, and if I remember correctly that's all it supported for a long time. RSA is still a very strong algorithm and has a few benefits over ElGamal. The main reason that people wanted to switch from RSA to something else was that until September of 2000 RSA was covered under a patent and required royalties to use.

    21. Re:Is 576bit big? by LnxAddct · · Score: 2, Insightful

      not too mention that currently factoring a 512 bit key will still take months, if not years. If someone is willing to put all that money and effort into cracking your key then you've got worse problems on your hands, I'd recommend buying a gun. My point is that just because one key was factored of that length, doesn't mean it is all the sudden faster or easier, it just means that a group of people put alot of effort, money, and thinking into one number and were able to factor that one number. They can't go around factoring 512 bit numbers at their whim now, these things still take time, and alot of it.

    22. Re:Is 576bit big? by Anonymous Coward · · Score: 4, Funny

      Someone might find some way to factor primes instantly via quantum computing, and your one-time pad would not be affected.

      That's definitely a good thing, because that instant prime-factorization algorithm has been around for centuries! Given a prime p, its factors are 1 and p.

      Still, for some reason, it seems like there's a Microsoft conspiracy to keep this knowledge from reaching the masses. What do they have to hide?

      "The obvious mathematical breakthrough would be development of an easy way to factor large prime numbers." Bill Gates, The Road Ahead, Viking Penguin (1995)

    23. Re:Is 576bit big? by Dwonis · · Score: 1

      primability test, eh? Is that like a probabilistic algorithm for testing primaility?

    24. Re:Is 576bit big? by ifwm · · Score: 1

      Um, no. Every problem you discuss that has to do with the reliability of one time pads is actaully a problem UNRELATED to one time pads.

    25. Re:Is 576bit big? by Sage+Gaspar · · Score: 1

      Well, there's also the question of how easy to relate and keep hidden the decryption tool is.

      For something like RSA encryption, the decryption tool (or rather, the piece of information necessary to enable the decryption tool) is small enough to be scratched out quickly on a piece of paper, passed on verbally or (albeit a bit harder) committed to memory, if necessary.

      For one-times, the decryption tool in question is as large as the message itself. That means that the tool must be itself stored somewhere semi-permanent, which means that it's more susceptible to theft.

    26. Re:Is 576bit big? by akruppa · · Score: 1

      RSA-576 2003 1881 C174=P87*P87 GNFS Bahr/Franke/Kleinjung/Montgomery/te Riele/Leclair/Leyland/Wackerworth

      The last name should be Richard Wackerbarth I think, not Wackerworth.

      Alex

      --
      Heisenberg may have been here
    27. Re:Is 576bit big? by JuggleGeek · · Score: 1
      Well, there is no uncrackable code.

      No? Tell me what this means...

      duiedl2aiaisadiieakeiawieaupqa
    28. Re:Is 576bit big? by N+Monkey · · Score: 1

      Wow, I havn't really read in to it, but is that very big? I mean, they were talking about not too long ago that 128bit encryption is "almost impossiable" to break. If this is 576bit encryption, and they've broken it, doesn't this mean that 1024bit is looking slightly weak? Whats the 'difficulty' of breaking this key on a relative scale?

      You're confusing symetric key ciphers (eg AES (Rijndael), DES, Blowfish etc) with the public/private key ciphers (RSA, Diffie-Hellman). The former can use any "random" pattern of bits as the key, whereas the latter need a much larger key size because they rely on certain numeric properties of the key or algorithm.

    29. Re:Is 576bit big? by mrtroy · · Score: 1

      If you are worried about the security of your data, just pump up the bits of the RSA key, and it will exponentially increase the time it would take to crack it basically.

      RSA is a nice little scheme, where you have a public key so that anyone can encrypt data for you, but you are the keeper of the private key. In Algebra, we learned how to actually encrypt and decrypt RSA with just a pencil and paper, and we quickly learned that computers are much quicker :P (i couldnt imagine doing a 128bit encryption using a pencil)

      The tough part for breaking an RSA scheme is basically related to factoring theory. I imagine these programs are very efficient and well designed, but still there are soooooo many possible values that nobody could crack your data in a reasonable amount of time.

      --
      [I can picture a world without war, without hate. I can picture us attacking that world, because they'd never expect it]
    30. Re:Is 576bit big? by Just+Some+Guy · · Score: 2, Interesting
      However, with Beowulf clusters and the new primability test, this is being offset quickly.

      No, the biggest Beowulf won't put a dent in the bit length. Consider a 1024-bit prime being tested by a gigantic 65536- (2^16) node cluster. You've now reduced the problem so that each machine has a mere 1008-bit (1024-16) search space. Put another way, parallelization is relatively useless against exponential algorithms.

      --
      Dewey, what part of this looks like authorities should be involved?
    31. Re:Is 576bit big? by tx_mgm · · Score: 1

      Well, there is no uncrackable code.
      No? Tell me what this means...

      duiedl2aiaisadiieakeiawieaupqa

      I can do that. No complex mathematical algorithms needed, either!
      I'll just need your home address and photos of any immediate family members....

      joke. laugh.

      Seriously, though, I think Mitnik (sp?) would have something to say about security vulnerabilities and human weakness. Which is why keys generated and used by computers (and usually unknown to the human using them) will ALWAYS be more secure than even the most obscure, cracked-out codes people can think of in their own heads.

      --
      Gentlemen...BEHOLD!
      -Dr. Weird
    32. Re:Is 576bit big? by chochos · · Score: 1

      when you hear about 128-bit encryption that is "almost impossible to break", they're talking about symmetric encryption keys.

      the article talks about a 576-bit RSA key. RSA is an asymmetric algorithm, it needs much bigger keys to make it hard to crack. a 128-bit RSA key can be cracked a lot easier than a 128-bit AES key (AES is a symmetric algorithm).

  4. That's Easy by paul248 · · Score: 4, Funny

    Look! I did it too!

    1 2 3 4 6 8 9 12 16 18 24 32 36 48 64 72 96 144 192 288 576

  5. Hmmm. Complexity vs. Cash by silentbozo · · Score: 4, Interesting

    Does anyone know the relative computational difficulty of cracking RC5-72 vs. trying to factor one of the RSA numbers? Given the higher monetary payoff, I'm wondering if I wouldn't be better off implementing and running a prime factor sieve, rather than running the RC5 client (which only runs on my W2k workstation, because the distributed folks never rewrote the older cores that run on my pre-OSX Macs.)

  6. Mersenne Primes by penguinoid · · Score: 2, Informative

    Mersenne primes are a number of the form 2^n - 1, where n is some prime number. Mersenne primes are one of the easiest to find, and there is a quick (relatively) algorithm for checking whether it is prime. Not all Mersenne numbers are prime.

    --
    Don't waste your vote! Vote for whoever you want, unless you live in a swing state it won't matter anyways
    1. Re:Mersenne Primes by millette · · Score: 4, Interesting

      the 40th Mersenne prime has been discovered 2-3 weeks ago and just proven to be correct. See http://www.mersenne.org/history.htm for more info.

    2. Re:Mersenne Primes by penguinoid · · Score: 1

      The exponent must be a prime as well, but it still won't guarantee you get another prime.

      --
      Don't waste your vote! Vote for whoever you want, unless you live in a swing state it won't matter anyways
    3. Re:Mersenne Primes by millette · · Score: 4, Informative
      and 4 isn't either... so really 2^4-1 is a terrible example.
      • 2^5-1 = 31 is prime
      • 2^9-1 = 511 isn't prime since 9 isn't
      • 2^11-1 = 2047 isn't prime: 23 x 89
    4. Re:Mersenne Primes by Zork+the+Almighty · · Score: 1

      You'd also NEVER want to use a Mersenne prime in RSA, which about the only way to bring this back on topic.

      --

      In Soviet America the banks rob you!
    5. Re:Mersenne Primes by nihilogos · · Score: 4, Insightful

      Algorithm for increasing karma:

      1. Read first paragraph of article.

      2. Find first occurence of technical term.

      3. Look up definition of said technical term on google.

      4. Cut and paste definition then post on relevent slashdot forum.

      The best part is, you can do all this without actually knowing anything about the topic!

      --
      :wq
    6. Re:Mersenne Primes by HappyFunnyFoo · · Score: 1

      That's incorrect. The logic is as follows: 1. IF 2^P - 1 is prime, THEN 2. P is prime. Since 2^4 - 1 is not prime, 4 is not prime. The theorem is true as such. Please RTA before posting.

    7. Re:Mersenne Primes by millette · · Score: 1

      Actually, my response was off-topic since the article only mentionned mersenne primes in passing. It certainly doesn't discuss any theorems. Instead of lashing at me gratuitously, maybe you should take a deep breath while reading the article yourself.

      If I can bring your attention here, you'll see why I imposed my condition the way I did.

      I say goodday!

    8. Re:Mersenne Primes by Alsee · · Score: 4, Funny
      --
      - - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
    9. Re:Mersenne Primes by Alsee · · Score: 1
      --
      - - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
    10. Re:Mersenne Primes by JuggleGeek · · Score: 1
      2^4-1 = 15, for instance

      Apparently you need a bit of education about mersenne primes.

      A mersenne number is defined by 2^N-1 where N is prime. If N isn't prime, it isn't a mersenne number. (In your example, 2^4-1=15, you didn't have a prime in the N spot, so you aren't even looking at a mersenne number.) Not all mersenne numbers are prime. In fact, most are not. If they were, it would be incredibly easy to find large prime numbers.

      2^N-1 is the basic math behind mersenne primes. It doesn't mean that you can plug any number into the N position and come up with a prime. However, if you go the other way, if 2^N-1 is prime, then N is prime, every time.

      If N is prime, 2^N-1 is not always prime. However, the likelyhood that it *is* prime increases dramatically as compared to testing a random number with the same number of digits.

      2^N-1 where N is not prime is meaningless, and has nothing to do with mersenne numbers.

      The point of using mersenne numbers is that testing large numbers (in the millions of digits range) can-and-does take a long time. Mersenne numbers are more likely to be prime than other numbers. So instead of testing everything, if you test just mersenne numbers, you are more likely to find large primes. Testing only the mersenne numbers doesn't mean that you'll find every prime number. There are almost certainly a large number of unknown primes with less than 6.3 million digits - but finding that largest one was based on testing a large number of mersenne numbers.

      http://www.mersenne.org/prime.htm will help if you want to know instead of spouting bullshit. There are links there which will explain the math, the history, etc. If you just want to talk without knowing what you are talking about, you are already on the right track.

    11. Re:Mersenne Primes by nihilogos · · Score: 1

      hehe

      --
      :wq
    12. Re:Mersenne Primes by jea6 · · Score: 1

      Google searches for karma whoring are on their way out. Current best practices invole wikipedia.

      --

      sarchasm: The gulf between the author of sarcastic wit and the person who doesn't get it.
    13. Re:Mersenne Primes by jrockway · · Score: 1

      Sorry, I made a mistake. Let it go :)

      --
      My other car is first.
  7. Re:Umm..k? by TedCheshireAcad · · Score: 5, Informative

    Not sure if this is a troll, but I may as well offer a simple explanation.

    The RSA public-key cryptosystem takes advantage of the theory that factoring composite numbers is a computationally difficult problem. I'm not going to get into specifics, but the depth of the problem is in that the composite number acts more or less as a public key, and encoded within that composite number (as one of the factors) is the private key.

    Being able to factor an RSA number is big news because it says that an RSA encoded message with a number of that size (576) can be defeated. Whether or not this is economical to defeat (i.e. time and resources put into the factoring effort) is really the key to this exercise, but one can now assume that a properly funded entity (most likely government) has the ability to defeat RSA-576.

    Hope this helps.

  8. Reaction by Angram · · Score: 5, Funny

    I think I speak for 99% of the population when I say...

    "Oh."

    --

    GL
  9. Cheaters! by Anonymous Coward · · Score: 3, Funny

    They probably just looked in the back of the book.

    1. Re:Cheaters! by endx7 · · Score: 5, Funny

      They probably just looked in the back of the book.

      No, that was an even problem. Only odd problems are in the back of the book.

    2. Re:Cheaters! by tatsu69 · · Score: 1

      No. Only odd numbered problems are in the back of the book not even problems.

    3. Re:Cheaters! by JoshWurzel · · Score: 1

      Your book is a lot more predictable than mine. In my textbooks (graduate structural engineering), the only answers in the back of the book are the SHORT ones. So the first chapters have every 2nd or 3rd problem. The last chapters, where the problems are hard and you actually NEED the solutions, only have every 6th or 7th problem.

      Geez, professors are lazy these days.

    4. Re:Cheaters! by HeghmoH · · Score: 1

      Shit. I spent four days solving RSA-577, and now you're telling me it's in the back of the frigging book??

      --
      Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
  10. RSA Challenge Challenge by Caractacus+Potts · · Score: 1

    Now there needs to be cash prize for discovering the discoverer when the challenge has been met. I just checked that site today.

  11. Re:Umm..k? by Snoopy77 · · Score: 4, Funny
    Soo......what does this mean? RSA-576 sounds like the name of a fighter plane.

    Well i_am_syco, articles are there for reading. They can even increase your knowledge, and one day you may even learn how to spell psycho properly.

    --
    "She's a West Texas girl, just like me" - G.W Bush Iraqis
  12. The Other One Percent by handy_vandal · · Score: 4, Funny

    I think I speak for 99% of the population when I say... "Oh."

    I think I speak for the other 1% when I say ...

    "Um."

    -kgj

    --
    -kgj
    1. Re:The Other One Percent by Anonymous Coward · · Score: 2, Funny

      And i speak for the HTML nazis when i say "Close your fucking tags!"

    2. Re:The Other One Percent by EvilSporkMan · · Score: 1

      ...and I speak for 99% of everyone when I say this has gone on too long.

      --
      -insert a witty something-
  13. Re:Hmmm. Complexity vs. Cash by TedCheshireAcad · · Score: 4, Insightful

    Well, the computational complexity of the General Number Field Sieve is:

    O(exp(c*log(n)^(1/3)*log(log(n))^(2/3)))
    where the value of c is reflected by the specific flavor of the NFS you're using, but in each case c>1

    I don't know the complexity of RC5, but I can imagine it's not exponential like the NFS.

  14. Re:Hmmm. Complexity vs. Cash by Ninja+Programmer · · Score: 2, Interesting

    Factoring composite is probably somewhat easier in the sense that it doesn't require more hardware/brute force computational power, however, its probably harder in the sense that you need to be very famillar with the very latest in factoring algorithms and essentially be skilled and willing enough to implement the very leading edge known algorithms.

    In other words, factoring RC5-72 requires Moore's law, plus a massively growing audience of people willing to participate. But even with the most optimistic projections, RC5-72 will not fall for decades. Factoring something like RSA-574 requires that you be up on the latest in computational mathematics as it relates to number theory. If you think you can bone up on the latest in factoring techniques in less than 10 years, then you probably have a better shot at the RSA prizes.

  15. Oh no... by RSA-576 · · Score: 5, Funny

    How could they *factor* ME without *my* own knowledge?! Somebody call the doctor... -RSA-576

    1. Re:Oh no... by monkease · · Score: 1

      ....sounds kinky....

  16. Notify RSA by TheRedHorse · · Score: 4, Informative

    In order to win the prize, you must submit your result to RSA, they don't actively seek out winners. That's why RSA's page hasn't been updated.

    They can submit their answer here.

    1. Re:Notify RSA by marko123 · · Score: 1, Funny

      One of these numbers is not prime. Check it out for yourself!

      --
      http://pcblues.com - Digits and Wood
    2. Re:Notify RSA by buttahead · · Score: 1

      hell, neither of them are numbers. window's calculator just coems up with "OE...barf".

    3. Re:Notify RSA by Zork+the+Almighty · · Score: 1

      Maple says they are both prime. Granted, it's a probabilistic algorithms, but the chance of failure is extremely low. What were you using ?

      --

      In Soviet America the banks rob you!
    4. Re:Notify RSA by marko123 · · Score: 1

      I was using a failed attempt at humour :(

      --
      http://pcblues.com - Digits and Wood
  17. Re:The factors were by TedCheshireAcad · · Score: 3, Funny

    Your first factor is composite, slick.

    This is a /. revolution, instead of spelling nazis, we now have composite number nazis.

  18. Germany? by gr8_phk · · Score: 4, Interesting

    I'm not suprised that someone has done it. Even the RSA site suggested 576 would fall soon. What I do find interesting is that it took 4 days for word to get out, and that the factorization was done in Germany. More interesting would be knowing what algorithm was used - is it new, or just further refinement of GNFS or MPQS with faster hardware?

    1. Re:Germany? by anthony_dipierro · · Score: 1

      Took 4 days for word to get to Slashdot, maybe. Mathpuzzle.com reported this 3 days ago.

    2. Re:Germany? by RealityMogul · · Score: 1

      read the article. They used a number seive. It sounds like they had some specialized hardware but the article doesn't give much detail.

    3. Re:Germany? by akruppa · · Score: 2, Interesting

      Specifically, they very likely used the NFS lattice siever written by Prof. Jens Franke, Thorsten Kleinjung and Friedrich Bahr. It's the fastest siever I know of, partially thanks to decend assembler optimization for different cpu types. Oh, and it's distributed under the GPL! The latest version is not on the net as far as I am aware, but an older version, and MPQS code, can be found at ftp://ftp.math.uni-bonn.de/people/franke/mpqs4linu x

      And Franke has worked with the BSI before, the RSA-160 announcement here
      mentiones that the sieving was done at the BSI, while for RSA-576 apparantly only parts of the post-processing were (perhaps the linear algebra?)

      Alex

      --
      Heisenberg may have been here
  19. 4 days and no mention on RSA's website? by product+byproduct · · Score: 4, Funny

    They're busy multiplying the two 87-digit factors by hand, just to be sure.

  20. Awww by JDWTopGuy · · Score: 4, Funny

    Crap, there go my plans to factor it myself.

    --
    Ron Paul 2012
    1. Re:Awww by RealityMogul · · Score: 1

      Seriously, I just started working on it last weekend. Oh well, I wanted the $200,000.00 prize anyways.

      At least it confirms that my big number multiplication rountines really work.

    2. Re:Awww by Tired_Blood · · Score: 1

      I know what you mean. A couple weeks ago I realized that my attempts wouldn't solve the problem fast enough. Looking at the answer, I figure it would've taken me ~10^74 years to get it on my own.

      But on that note, there's no mention of how long it took them and how many computers were used.

      I'm relieved that I semi gave up before learning of this news. Oh well, at least I learned a great deal in the process.

      --
      This is not my sig.
    3. Re:Awww by JDWTopGuy · · Score: 1

      Man, I had no idea that was so funny... I was actually serious (okay, semi-serious), in fact I downloaded the text file of RSA-576 a few weeks ago. If you don't believe me, browse my journal... you'll see a reference to it. (I'm too lazy to provide a link.)

      But now I have at least one clue: both factors were of equal length, and were both half the length of the full number... anybody got any other hints? RSA-640, here I come!

      --
      Ron Paul 2012
  21. Or RC5-72 could fall tomorow by Veramocor · · Score: 1

    ......if you get lucky!

    There is nothing that says you won't find the correct key in the 1st .1% of keyspace you search.

    --
    Veramocor
    1. Re:Or RC5-72 could fall tomorow by swillden · · Score: 1

      There is nothing that says you won't find the correct key in the 1st .1% of keyspace you search.

      For that matter, there is nothing that says you won't guess the key on your first try!

      My Mom always told me it's better to be lucky than smart.

      --
      Note to ACs: I usually delete AC replies without reading them. If you want to talk to me, log in.
  22. Re:Umm..k? by Shadwell · · Score: 1

    one day you may even learn how to spell psycho properly.

    Not a big Suicidal Tendencies fan are you? :P

  23. Symmetric vs. public-key cyphers... by Goonie · · Score: 5, Informative
    I'm not an expert, but IIRC you're talking about apples and oranges here.

    When 128-bit cyphers are described as "secure", they're almost certainly talking about symmetriccyphers - that is, the key you use to encrypt the message is the same as the key you use to decrypt the message. There are no known ways to break currently acceptable symmetric cyphers (such as 3-DES and AES) faster than brute force - that is, trying each key one at a time. If you have a 128-bit key, this will on average take (2^128 / 2 = 2^127 ~= 10^38) tries before you get the key. This will take billions of years to do, even using a massively parallel computer.

    The other sort of encryption, the sort we are talking about here, is public-key encryption, where you use two different keys to scramable and descramble the message. The advantage of this method is you can create a key pair, and give one key to everyone who wants to send you a message (the public key), and while they can send you message securely, it is very difficult for them to figure out your private key (and thhus read messages other people have sent you).

    The bad news with public-key encryption is that the algorithms are considerably weaker than with secret-key cyphers. You can mount considerably quicker attacks than just brute-forcing the keyspace. Therefore, you need longer keys for equivalent levels of security. With RSA, the most common method, figuring out your private key from your public key is done by trying to figure out the factor of a very, very large number that is the product of two very large prime numbers. This is still very difficult to do, but it is a simpler problem than brute-forcing an entire keyspace. These Germans have just demonstrated the ability to factor a larger such number than anyone else has done before.

    Whilst this is interesting, from what (little) I understand of cryptography it's still a very long way from here to cracking 1024 bit RSA keys. In any case, as the hardware makes it easier for the attackers, it makes it practical to go with longer encryption keys, so faster hardware is neither a help nor hindrance to attackers. The one proviso is, of course, the security of data encrypted by older cyphers.

    --

    Any sufficiently advanced technology is indistinguishable from a rigged demo
    --Andy Finkel (J. Klass?)
    1. Re:Symmetric vs. public-key cyphers... by randombit · · Score: 3, Interesting

      There are no known ways to break currently acceptable symmetric cyphers (such as 3-DES and AES) faster than brute force

      Just a quibble: you can actually break both 3DES and AES faster than brute force. In the cast of 3DES, there is a time/memory tradeoff, and AES has some key schedule weaknesses (though in the case of AES, you need to collect nearly the entire codebook before you can proceed with the attack (at least the one I'm thinking of)). Basically, you're right in practice, just not in theory; none of the (publicly known) attacks on 3DES or AES are remotely close to being practical in any sense of the word.

      In any case, as the hardware makes it easier for the attackers, it makes it practical to go with longer encryption keys, so faster hardware is neither a help nor hindrance to attackers.

      Actually, the win is probably for the defenders. Double the length of an RSA key, the encryptor has to do 3-4 times as much work, but the person trying to factor it faces an increase that is much, much larger.

  24. Mine is 1024 too... by Trejkaz · · Score: 1

    My key is 1024 too... but it's ElGamal. Is the ElGamal algorithm inherently more or less secure than RSA?

    --
    Karma: It's all a bunch of tree-huggin' hippy crap!
    1. Re:Mine is 1024 too... by Stephan+Schulz · · Score: 4, Informative
      Is the ElGamal algorithm inherently more or less secure than RSA?
      RSA is based on the factorization of large numbers. El Gamal is based on the discrete log problem in a cyclic group. We don't know polynomial solutions for either problem, but we also do not have a strong lower bound for the complexity of either problem. I think currently El Gamal is regarded as slightly more secure, if only because more progress has been made with factorization (probably because its better known and easier accessible/explainable). In practice, it should not matter until some real mathematical breakthrough.
      --

      Stephan

    2. Re:Mine is 1024 too... by macmouse · · Score: 2, Informative

      Yes!
      Especially, if you are using gnupg.

      There has been an big compromise found using elgamel keys and GnuPG!

      http://www.auscert.org.au/render.html?it=3648&ci d= 1

    3. Re:Mine is 1024 too... by Trejkaz · · Score: 1

      RTFA.

      ESB-2003.0820 -- GnuPG Security Advisory -- GnuPG's ElGamal signing keys compromised
      ...
      Note that the standard keys as generated by GnuPG (DSA and ElGamal encryption) as well as RSA keys are NOT vulnerable.

      --
      Karma: It's all a bunch of tree-huggin' hippy crap!
    4. Re:Mine is 1024 too... by infolib · · Score: 1

      I think currently El Gamal is regarded as slightly more secure, if only because more progress has been made with factorization (probably because its better known and easier accessible/explainable)

      What is the logic here? I'd think that the more studied system would be considered most secure? Posters here seem to agree it's easy to pick an RSA key long enough to stop Eve - even when she has the spiffiest math and fastest computers. Then why not choose RSA when it's been attacked with some success but still holds up beautifully?

      Hope you can clarify a bit - after all you're the Dr. rer.nat. :-)

      --
      Any sufficiently advanced libertarian utopia is indistinguishable from government.
    5. Re:Mine is 1024 too... by joeblarnystone · · Score: 2, Informative

      There is an Index Calculus Algorithm for computing Discrete Logarithms that is analogous to the Quadratic Sieve method for factoring integers. Similarly there are variants that will solve the discrete logarithm problem over the integers modulo n in time comparable to the Number Field Sieve, which is what was used to factor this particular number from RSA. The only reason we don't hear about ElGamal Keys being broken is that there aren't big rewards for such an accomplishment, and because ElGamal another other Discrete Log based systems are not as widely used in practice. Certicom does have a contest to compute discrete logarithms over the group found by taking points on an elliptical curve. These problems aren't as popular to solve it seems, in part I imagine because there is no good way to solve the problem when your group is the points on an elliptical curve. (So an interesting result of this is that the keys for discrete log systems over elliptical curves are MUCH smaller,)

    6. Re:Mine is 1024 too... by Stephan+Schulz · · Score: 1
      What is the logic here? I'd think that the more studied system would be considered most secure? Posters here seem to agree it's easy to pick an RSA key long enough to stop Eve - even when she has the spiffiest math and fastest computers. Then why not choose RSA when it's been attacked with some success but still holds up beautifully?
      The more studied system is only more secure if no weaknesses turn up. For factoring, we do have had quite significant progress over the last years, and promises for more. Now, this is the kind of progress that moves breakbility from 10e26 processor years to 10e25 processor years or so, but still, it is there.

      As somebody else already mentioned, there now seems to be similar progress for the discrete log problem used by ElGamal, so I don't know if my original statement still holds in the cryptographic community.

      Hope you can clarify a bit - after all you're the Dr. rer.nat. :-)
      Hey, not fair! I'm not an Austrian, after all ;-)

      When my theorem prover is used in cryptographic applications, one of the assumptions is usually that the cypher is unbreakable and that the protocol is the weak part. And how either theorem proving or cryptography end up under "natural things" is anybody's guess.

      --

      Stephan

  25. Re:The factors were by paul248 · · Score: 1

    Yeah, I noticed that after posting, but it's not trivial to generate a 173-digit prime, so I just faked it with rand(). On second thought, I should have at least made sure the last digit was 1, 3, 7, or 9. But what's done is done.

  26. Re:Hmmm. Complexity vs. Cash by couchslayer · · Score: 2, Funny
    I read this quickly and agreed that NFS does have exponential complexity, and is impossibly slow. Damn Network File System!

    --
    If a woodchuck could, would it be too lazy to?
  27. Re:Actually by imyourfoot · · Score: 1

    2 is prime, genius.

  28. Re:Umm..k? by Snoopy77 · · Score: 1

    The sad thing is that just like Axl Rose, they probably thought they were spelling it correctly.

    --
    "She's a West Texas girl, just like me" - G.W Bush Iraqis
  29. Re:RC5-76, not 576! by Bombcar · · Score: 3, Informative
    Not So! Read the site! A 76 bit number is not 174 decimal digits!

    RSA-576

    Prize: $10,000

    Status: Not Factored

    Decimal Digits: 174

    188198812920607963838697239461650439807163563379 41
    738270076335642298885971523466548531906060650474 30
    453173880113033967161996923212057340318795506569 96
    221305168759307650257059

    Digit Sum: 785
  30. Is it me, or is this story... by pr0ntab · · Score: 1, Offtopic

    attracting only comments from old troll accounts?

    No one knows anything about how you go about factoring huge composite numbers, or can read German, or even knows the difference between breaking RSA-576 and breaking RC5-72.

    So all that's left are people trying to find clever ways of linking to the prime number shitting goatse, and a surprising dearth of posts by abandoned troll accounts.

    Care to explain?

    --
    Fuck Beta. Fuck Dice
    1. Re:Is it me, or is this story... by plcurechax · · Score: 4, Informative

      attracting only comments from old troll accounts?

      No one knows anything about how you go about factoring huge composite numbers...


      Mathematics has the problem that the general population has listened to claims that "math is hard" and has learnt to ignore any attempt at understanding mathematics beyond useless trivia and professional sports statistics.

      To help make some sense of what they are discussing:

      Some factoring theory and source code by Paul Herman and Ami Fischman.

      From RSA Labs' FAQ - What are the best factoring methods in use today? a fairly technical but readable description of advanced factoring algorithms, and What improvements are likely in factoring capability?

  31. Easily Multiplied Numbers !!?? by Proudrooster · · Score: 4, Funny

    And I quoth from the article:
    3980750 8642406493 7397125500 5503864911 9906436234 2526708406 3851895759 4638895726 1768583317
    x
    4727721 4610743530 2536223071 9730482246 3291469530 2097116459 8521711305 2071125636 3590397527
    which can easily be multiplied to verify that they do indeed give the original number.


    Does anyone have a calculator that can "easily" multiply these two numbers... Holy Cow!

    1. Re:Easily Multiplied Numbers !!?? by Zork+the+Almighty · · Score: 1

      I think you were typing on one a minute ago.

      --

      In Soviet America the banks rob you!
    2. Re:Easily Multiplied Numbers !!?? by buford_tannen · · Score: 3, Informative
      Try GNU bc:
      39807508642406493739712550055038649119906436234252 6708406385189575946388957261768583317 * 47277214610743530253622307197304822463291469530209 7116459852171130520711256363590397527

      188198812 92060796383869723946165043980716356337941738270076 33564229888597152346654853190606065047430453173880 11303396716199692321205734031879550656996221305168 759307650257059
      See? That was easy enough. And it would have been even easier if i hadn't had to remove all those spaces you put in there! :)
      --
      Buford "Mad Dog" Tannen
    3. Re:Easily Multiplied Numbers !!?? by buford_tannen · · Score: 1

      My apologies... slashcode appears to have put those spaces there.

      Stupid slashcode.

      --
      Buford "Mad Dog" Tannen
    4. Re:Easily Multiplied Numbers !!?? by Platinum+Dragon · · Score: 2, Funny

      Does anyone have a calculator that can "easily" multiply these two numbers...

      A pencil and paper seem to do a great job at storing the values for calculation. As for actually carrying out the calculation, that's what your brain cells are for.

      They said "easily". They didn't say "quickly". :-)

      --

      Someday, you're going to die. Get over it.
    5. Re:Easily Multiplied Numbers !!?? by Ageless · · Score: 4, Interesting

      I'm sure Slashcode will eat this Java source for lunch, but here we go.

      import java.math.*;

      public class Calculator
      {
      public static void main(String[] args)
      {
      BigInteger x = new

      BigInteger("398075086424064937397125500550386491 19 9064362342526708406385189575946388957261768583317" );
      BigInteger y = new

      BigInteger("472772146107435302536223071973048224 63 2914695302097116459852171130520711256363590397527" );
      BigInteger z = x.multiply(y);
      System.out.println(z.toString());
      }
      }

      [c:\temp]\j2sdk1.4.2_01\bin\javac Calculator.java

      [c:\temp]java Calculator
      18819881292060796383869723946165043980 716356337941 73827007633564229888597152346654853190606065047430 45317388011303396716199692321205734031879550656996 221305168759307650257059

    6. Re:Easily Multiplied Numbers !!?? by acermate433s · · Score: 1

      heck! even excel cannot multiply this numbers.

    7. Re:Easily Multiplied Numbers !!?? by wmspringer · · Score: 1

      Try Maxima; it's a free, open source computer algebra system that can handle numbers of arbitrary length.

      Coincidentally, I was just using it to factor a (much smaller) RSA-encrypted message last week for a class..

    8. Re:Easily Multiplied Numbers !!?? by Krach42 · · Score: 1

      famine ~$ bc
      bc 1.06
      Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
      This is free software with ABSOLUTELY NO WARRANTY.
      For details type `warranty'.
      3980750864240649373971255005503864911 9906436234252 6708406385189575946388957261768583317*472772146107 43530253622307197304822463291469530209711645985217 1130520711256363590397527
      18819881292060796383869 723946165043980716356337941 738270076335642298\
      88597152346654853190606065047 430453173880113033967 161996923212057340\
      31879550656996221305168759307 650257059

      It's all about finding the write language for the problem. I think I spent more time writing this paragraph than putting the problem into BC.

      --

      I am unamerican, and proud of it!
    9. Re:Easily Multiplied Numbers !!?? by Krach42 · · Score: 1

      yeah, it plops in the spaces because people would abuse the system, and make links that would span across the entire page causing icky horizontal scroll bars.

      --

      I am unamerican, and proud of it!
    10. Re:Easily Multiplied Numbers !!?? by SirHalcyon · · Score: 1

      echo 39807508642406493739712550055038649119906436234252 6708406385189575946388957261768583317*472772146107 43530253622307197304822463291469530209711645985217 1130520711256363590397527 | bc

    11. Re:Easily Multiplied Numbers !!?? by Hadlock · · Score: 1

      aha - i was wondering why that happened on long urls, also. much thanks.

      --
      moox. for a new generation.
    12. Re:Easily Multiplied Numbers !!?? by JohnPM · · Score: 2, Informative

      In python:

      print 39807508642406493739712550055038649119906436234252 6708406385189575946388957261768583317 * \
      47277214610743530253622307197304822463291469530209 7116459852171130520711256363590397527

      --
      Karma police, I've given all I can, it's not enough, I've given all I can, but we're still on the payroll.
    13. Re:Easily Multiplied Numbers !!?? by Ageless · · Score: 1

      Oh sure, but my version Runs Everywhere! ;-)

    14. Re:Easily Multiplied Numbers !!?? by Krach42 · · Score: 1

      Yeah, and it breaks & encoded HTML entities also, so in case you're wondering why you end up with some weird stuff sometimes... that's why.

      Don't submit this as a bug though, since you'll get yelled and bitched at. (like I have at least a few times) They insist that breaking apart elements that will get rendered as a single character should still be considered to be the length of the sum of the lengths of the individual elements.

      --

      I am unamerican, and proud of it!
    15. Re:Easily Multiplied Numbers !!?? by Krach42 · · Score: 1

      Oh now that's just not nice.

      --

      I am unamerican, and proud of it!
    16. Re:Easily Multiplied Numbers !!?? by elmartinos · · Score: 1

      Everybody here has. Just use the Google calculator. Well, at least the first few digits can be compared.

      Probably the simplest solution is to use Ruby:
      ruby -e "p 39807508642406493739712550055038649119906436234252 6708406385189575946388957261768583317 * 47277214610743530253622307197304822463291469530209 7116459852171130520711256363590397527"

      which prints
      18819881292060796383869723946165043980716356337941 73827007633564229888597152346654853190606065047430 45317388011303396716199692321205734031879550656996 221305168759307650257059

      You have to remove the spaces, slashdot seems to automatically add them.

  32. How long did it take them? by ajiva · · Score: 1

    I don't see anything about how long it took them! I do know that RSA-155 took 7 months of computation to break...

  33. Worried about your keys? by Anonymous Coward · · Score: 5, Informative

    not being the math wiz that most /.ers are I was wondering what this meant for me...I found the below statement on RSA's FAQs and it answered my question that I'm sure many here like me have..
    ***************
    What does it mean when a Challenge Number is factored?

    Users of the RSA public-key cryptosystem may wonder what the factoring of a challenge number implies about the security of their keys. Should they immediately replace their keys with larger ones? Should they stop using RSA altogether?

    Clearly, the factoring of a challenge-number of specific length does not mean that the RSA cryptosystem is "broken." It does not even mean, necessarily, that keys of the same length as the factored challenge number must be discarded. It simply gives us an idea of the amount of work required to factor a modulus of a given size. This can be translated into an estimate of the cost of breaking a particular RSA key pair.

    Suppose, for example, that in the year 2010 a factorization of RSA-768 is announced that requires 6 months of effort on 100,000 workstations. In this hypothetical situation, would all 768-bit RSA keys need to be replaced? The answer is no. If the data being protected needs security for significantly less than six months, and its value is considerably less than the cost of running 100,000 workstations for that period, then 768-bit keys may continue to be used.

    Applications that require longer-term security or have data with a high financial value should migrate to longer keys before the factoring of the corresponding challenge number is announced. In either case, the results of the Factoring Challenge provide real data to help the cryptosystem user choose the appropriate key size.

    RSA Laboratories' Frequently Asked Questions About Today's Cryptography provides more information on choosing RSA key lengths for various applications. RSA Laboratories Bulletin #13 discusses key length requirements for various cryptosystems.
    ***********************
    And honsetly I think for most people the idea of someone devoting a cluster of computers just so they can read some documents you may have on your hard drive kindof egotistical for the end user...but hey we all know that the NSA breaks every key they can right?...even ones from people just trying to protect their data from average joe hackers...

  34. dnetc as trojan by rwade · · Score: 2, Informative

    Norton AV's flagging of dnetc is fully in error. The distributed.net staff is aware of the situation and is working with Norton to resove the issue.

  35. Re:Umm..k? by Night+Goat · · Score: 1

    Suicidal Tendencies spells it Cyco, not Syco. As in "Born to be Cyco." So the guy's still a bad speller.

  36. Post Quantum Crypto by Multics · · Score: 2, Insightful
    Perhaps I should submit this as an Ask Slashdot instead of a comment here, but what happens when the quantum computers make breaking these things easy? (I'll leave out the word trivial since I can't imagine quantum computing being trivial anytime soon.)

    What will be the face of the next from of Crypto? Only one-time pads? That sounds way painful.

    -- Multics

    1. Re:Post Quantum Crypto by freuddot · · Score: 2, Informative

      > but what happens when the quantum computers
      > make breaking these things easy?

      People start using quantum cryptography. There already are commercial products offering you unconditial security, based on quantum computing, whereas the quantum computer is not ready to factor anything larger than 21...

      J.

    2. Re:Post Quantum Crypto by Nasarius · · Score: 2, Insightful

      Go read Bruce Schneier ("Applied Cryptography"). He basically proves that it would require insane amounts of energy at near-perfect efficiency to even iterate through every possible 256-bit number. No, your 256-bit symmetric keys and maybe 4096-bit asymmetric keys are quite safe from brute force attacks, forever. That's just the laws of physics.

      --
      LOAD "SIG",8,1
    3. Re:Post Quantum Crypto by billstewart · · Score: 3, Informative
      Quantum computers are too speculative at the moment, but they're the main new threat to near-exponentially-strong crypto algorithms. (Moore's law is theoretically a problem, but it can only continue for so long, and theoretical breakthroughs in the mathematics of factoring or a constructive proof of P=NP don't sound likely but could happen.) But they need to have a really high resolution to be any real threat at all - the Heisenberg limit of ~10**-47 only gets you ~150 bits, so you need to have large numbers of separate qubits coupled together to a be useful, rather than one highly-precise device.

      For symmetric algorithms, like the DES family, at most they're expected to cut the number of bits of algorithm strength in half, so instead of 3-DES you might need to use 5-DES or 7-DES, which is only a minor annoyance. For key distribution, it does mean returning to systems based on key distribution centers, like Kerberos. That's a big loss of functionality, unless we find asymmetric algorithms that quantum computing can't break. I'm not aware of any results on whether elliptic curve algorithms are susceptible to Quantum Computers, though it's possible that that could also happen.

      --

      Bill Stewart
      New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
    4. Re:Post Quantum Crypto by wmspringer · · Score: 1

      My guess would be whoever has access to the computer that can do it, claims a $625,000 reward for cracking the remaining codes...

      But seriously, unbreakable quantum encryption is available now; it doesn't even require a quantum computer. It's just less convenient and more expensive than RSA since it requires special equipment.

    5. Re:Post Quantum Crypto by Ibag · · Score: 4, Informative

      Actually, if you assume that quantum computing becomes main stream and people have enough qbits to factor large numbers (It was only like a year ago that IBM built a 7 qbit computer and implemented Shor's algorithm to factor 15), then you have one time pads being very possible.

      One of the nice things about quantum computing is that you can send a message to someone and tell if anybody intercepted it. Therefore, you can send one time pads until one gets through without being viewed. Once you have a one time pad, you can encrypt your message and send it fairly easaily using conventional means.

      Of course, I don't know what will happen with things like authentication which rely on public key schemes. I don't believe that eliptic curve encryption methods have an easy attack from quantum computing, but I don't know enough to say that they can be used for anything but encryption.

    6. Re:Post Quantum Crypto by Alsee · · Score: 1

      21? No way! 21 is a seriously tough nut to crack. The latest breakthrough was cracking 15. Quantum factored

      -

      --
      - - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
    7. Re:Post Quantum Crypto by Andy_R · · Score: 2, Funny

      I use LJ-5, which I believe to be sufficently safe.

      No-one is going to wade through 5 pages of a Live Journal blog to find my secrets.

      --
      A pizza of radius z and thickness a has a volume of pi z z a
  37. I was questioning the low IQ in the discussion... by pr0ntab · · Score: 1

    not the number factoring methods. I was speculating that most of the posters had no way of intelligently commenting on the story, as significant as it once. Thanks for the links, though.

    --
    Fuck Beta. Fuck Dice
  38. Re:Actually by jrockway · · Score: 1

    49561029139355845747971386346688559685802770654976 22183978317743925946576415078139905781369527613655
    898568246775450799399763584829976638122052329279 42
    9846895584179343292612 8 is composite, genius.

    First means the first one. Not the second one.

    --
    My other car is first.
  39. Re:Umm..k? by Dwonis · · Score: 1
    but one can now assume that a properly funded entity (most likely government) has the ability to defeat RSA-576. [Emphasis added]

    The authors of Microsoft-product-exploiting worms might have more computing resources available than any government by now.

  40. Linkage by Nasarius · · Score: 2, Informative

    Dunno if this is authorized, but: Appropriate Link

    --
    LOAD "SIG",8,1
    1. Re:Linkage by jrockway · · Score: 1

      Just curious, is that a warez'd copy of the book? It seems strange for that to be online in its entirety.

      --
      My other car is first.
    2. Re:Linkage by rimmon · · Score: 2, Informative

      http://www.cacr.math.uwaterloo.ca/hac/ It's legal :-)

  41. Python by Quixotic137 · · Score: 1

    Python can do this, and any arithmetic with arbitrarily large numbers (up to the limit of available memory).

  42. Re:Hmmm. Complexity vs. Cash by swillden · · Score: 5, Informative

    I don't know the complexity of RC5, but I can imagine it's not exponential like the NFS.

    The complexity of RC5 is O(n). Encryption time is constant but key setup time is linear, so the whole process is linear.

    However, that's not relevant. What you need to compare is the complexity of a brute-force search of an n-bit keyspace, which is O(2^n). Definitely exponential.

    --
    Note to ACs: I usually delete AC replies without reading them. If you want to talk to me, log in.
  43. Distributed Computing by anaphora · · Score: 2, Funny

    This looks like a prime job for distributed computing. Code a program that does this distributed, offer people xxx dollars per work calculation with a $1000 bonus if their calculation is correct. Deduct a few thousand for yourself, and voila. Crack the hardest code.

    1. Re:Distributed Computing by HeghmoH · · Score: 2

      This would be an amazing idea if somebody hadn't already been doing it for the past six years.

      --
      Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
    2. Re:Distributed Computing by alehmann · · Score: 1

      The General Number Field Sieve has four different stages, and only the first is very parallelizable. http://www.nfsnet.org/ is a distributed computing project that distributes the first stage of GNFS. The last 3 are run in-house (at Microsoft, in fact).

  44. Latest Cryptography Breakthrough by Anonymous Coward · · Score: 1, Interesting

    Here is the latest cipher with perfect secrecy, with an added assumption on the memory limits of the adversary.

  45. Shamir's TWINKLE and TWIRL machines by billstewart · · Score: 2, Interesting
    Beowulf clusters aren't any threat to 1024-bit RSA - you're not going to put enough machines in a room to do the job, nor are you likely to put enough on the continent. On the other hand, for smart cards and cash machines and "export-approved" software with 512-bit keys in them, they're starting to really kick ass.

    The real threat is Shamir's TWIRL and TWINKLE optical factorization-assistance gadgets. They aren't necessarily a threat to 1024-bit keys, but they're a definite threat to 768-bit keys, and it's time to start thinking seriously about threat models before embedding 1024-bit limitations in hardware. That's probably big enough that only national governments are likely to be funding, rather than bank robbers and other Mafiosi.

    --

    Bill Stewart
    New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
    1. Re:Shamir's TWINKLE and TWIRL machines by tomstdenis · · Score: 2, Interesting

      Actually you'd be surprised. RSA-1024 will require [at least] 2^43 bits of ram and roughly 2^87 time to complete. There is enough room in my bedroom to put such a computer.

      The problem is the 2^87 time [oh and the insane heat it would make...!] [for those out of a clue 2^43 bits is 1TB of memory]

      Tom

      --
      Someday, I'll have a real sig.
  46. Re:Umm..k? by Pinball+Wizard · · Score: 1
    Being able to factor an RSA number is big news because it says that an RSA encoded message with a number of that size (576) can be defeated.


    Just a clarification...I know you probably know what you meant, but a casual reader may not...this is not a 576 digit number, but a 576 bit number - the value is on the order of 2^576 - a f*'in big number to factor.

    --

    No, Thursday's out. How about never - is never good for you?

  47. What if one day... by tangent3 · · Score: 1

    What if one day someone discovers an miraculous way to easily factorizes a large number in no time. Would it be outlawed by the DMCA?

  48. Global Warming by Anonymous Coward · · Score: 1, Interesting

    Factoring RSA-2048 might considerably contribute to global warming due to computer activity. Got anybody an idea how big the temperature rise will be assuming the efficiency given by the RSA-576 challenge?

    I still remember homework about a driver being stopped because he ignored a red traffic light. He claimed the light was green because of Doppler shift caused by high speed of the car. The amount of fuel required to reach this speed was by far higher than the total consumption by mankind.

    1. Re:Global Warming by Gannoc · · Score: 2, Funny
      I still remember homework about a driver being stopped because he ignored a red traffic light. He claimed the light was green because of Doppler shift caused by high speed of the car. The amount of fuel required to reach this speed was by far higher than the total consumption by mankind.


      I hate to be the one to tell you this, but most of your homework problems didn't actually happen in real life. For example, there probably isn't a train leaving san franciso and denver at the same time at different speeds heading towards each other on parallel tracks.

  49. Use Google! by Maddog+Batty · · Score: 1

    Google accepts the sum but only gives 9 sig figs in the answer. Oh well.

    --
    wot no sig
  50. Use Ruby! by DB_researcher · · Score: 1

    The Ruby will help you.
    This is an OO interpreter which can multiply big integers without any additional modules.

  51. RSA and pseudo primes by thogard · · Score: 1

    RSA's security is based on there being only two primes that make up the magic numbers. The RSA contests are about the difficult problem of factoring primes however that isn't the only hard problem that RSA encryption depends on. Another problem is the Euclidian algorithm which I feel is the main weakness. The problem is that there isn't a 1:1 ratio of public keys to private keys and there may be a very large number of private keys that will decrypt a given public key.

  52. OK - but how much force does this actually take? by jpellino · · Score: 1

    So far they seem give you the dates of the completions, but not the time / cpu hours taken.
    Even the distributed.net doesn't seem to have seti-like stats on cpu hours used.
    This seems to take more than a single cpu and workaday time.
    Without those numbers on actual cpu time needed, this seems like flagpole-sitting.
    The public perception would be that anyone with a workstation and some time on their hands might do this if the methods are 'just math' and made public.

    --
    "Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
  53. When I win the lottery... by Overzeetop · · Score: 1

    ...I'm going back to school to study cryptography. It's just too damned cool (and I used to be a rocket scientist, a cool vocation itself).

    --
    Is it just my observation, or are there way too many stupid people in the world?
    1. Re:When I win the lottery... by bhima · · Score: 1

      On you sig, my theory is that total IQ available to the world is a constant.

      --
      Nothing in the world is more dangerous than sincere ignorance and conscientious stupidity.
  54. Cracking old messages? Come on... by Chemisor · · Score: 2, Funny

    > Those people could be concerned at this point that
    > their old messages could be cracked.

    Who would want to spend zillions of hours of computer time to read some geek's old messages?

    "Great news, today I have finally managed to install the latest 0.99.1 kernel and boy is it great! I'm so glad I picked SLS instead of slackware, whose installer sucks big time. With my beloved SLS all I had to do was swap four floppies in and out and everything works beautifully! No crashes yet. I never realized how much of a pain DOS was! I just finished getting my printer to work (sure was tough, see attached comments on my 7551 hack) and am bored stiff. Do you know if there are any games for Linux? Moria just doesn't cut it after King's Quest."

  55. obligatory perl version by djtack · · Score: 1
    perl -Mbigint -e 'print 39807508642406493739712550055038649119906436234252 6708406385189575946388957261768583317 * 47277214610743530253622307197304822463291469530209 7116459852171130520711256363590397527'
  56. Re:Hmmm. Complexity vs. Cash by Morgo · · Score: 1

    which only runs on my W2k workstation, because the distributed folks never rewrote the older cores that run on my pre-OSX Macs.

    Have you tried mailing d.net about porting the clients to older Macs? They should be able to find someone willing to do it, although I admit the latest clients on their download page are very old.

    I know for a fact that RC5-72 cores for PPC were made, because I wrote some of them :-)

  57. Here's a couple. by Tired_Blood · · Score: 1

    Man, I had no idea that was so funny...
    It is funny. Or at least, I'd rather laugh than cry. (note: I'm trying to be funny here).

    But now I have at least one clue: both factors were of equal length, and were both half the length of the full number
    The length of a product is equal to the sum of the lengths of it's factors (1/3 of the time it's less one). That part shouldn't be a surprise. Of the 45 different single digit multiplications (I'm excluding the use of 0), 30 produce a double digit product. 1*anything results in a single digit product, 2*2,3,4 also and 3*3. The sum_of_lengths idea for multiplication applies to all bases, not just decimal.
    When I read their faq, I got the impression that the factors will be approximately of equal length (when read in binary). They also want to make it 'impossible' to crack it brute-force using a prime number list. If one factor is much smaller, then it'll be less effort using the bottom-up approach we all used in 3rd grade (x/2, x/3, x/5, x/7, etc).

    I put a lot of time into the project so I won't just give it all away (see *NOTE* below). But I'll provide a couple ideas:
    1. The two factors are prime. Being that both are odd values, their average will always be a whole number.
    2. The average is always greater-than or equal-to the square-root of the product.
    Now look up Fermat's method. It's the basis for most/all factoring algos. Here's a link. I don't necessarily like the way they describe it (there are easier ways), but it's a hint - just like you asked.

    I regularly get new ideas on how to improve my approach, but each one shaves (on average) half the time. Half of ~10^74 years is still ~10^74 years. I am only using one computer, so that's one hinderence...

    Here's another hint: don't use bottom-up as your main approach, it's a bigger waste of time than 10^74 years since you're guaranteed that the lower value is not small. Recall that RSA implements the use of two LARGE factors. 'Large' is definitely subjective but is relative to the given value.

    I looked at your journal. The hints above help provide ways to skip large sections. 'Large' is again subjective.

    Since I mentioned the journal, sorry - I'm not a fan of Descent. I just couldn't get used to the controls and navigating upside-down/sideways and so forth.

    I'm sorry if this disappoints you, but I'm sure there's some quick and dirty way to find the answer without brute force. My opinion is that you just have to REALLY think different (like rejecting division or something just as radical), since no one's done better with the tools available. A historical analogy would be something like the introduction of polar coordinates or logarithmic scales - departures from conventional techniques to simplify a particular difficulty.
    ... hmmm ....


    NOTE: I need to feel that it's actually worth something even though it's probably not.

    --
    This is not my sig.
    1. Re:Here's a couple. by JDWTopGuy · · Score: 1

      Thanks! I'm going to save this somewhere so I don't lose it.

      I had already figured that starting at the bottom would be an idiotic thing to do. I was thinking of setting up a distributed system, starting smack-dab in the middle of the "likely" range, and moving in both directions. That way there's no need to specify a range; simply continue until you find what you're looking for.

      And yes, I know that it requires either lots of time, or incredible luck. I have the CPU-time, and friends who may donate CPU-time. (Who wouldn't donate CPU-time for potential cashola?)

      Which specific project are you talking about? An attempt at RSA-576, or another number?

      --
      Ron Paul 2012
    2. Re:Here's a couple. by Tired_Blood · · Score: 1

      I was talking about RSA-576. That's how I could estimate the time-to-answer.

      I'd still like to know the amount of resources and time expended for their project. Knowing that info would tell me how my solo attempt compares.

      Also, you just know that they're working on the next ones too.

      --
      This is not my sig.
  58. Re:ut_radio 9 8 by bobbozzo · · Score: 1
    you made this name just to grab karma, didn't you?

    Too bad then that there's no karma bonuses on ++funny

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    Nothing to see here; Move along.