It is perfectly possible to deterministically alter an encrypted message.
Sure, but how does including the hash prevent that from working? That is why you would use a digital signature system as I said in my other message. A hash by itself is worthless for verifying the sender of the message. As I said, a hash is typically part of a digital signature system, but by itself it does nothing to verify the identity of the sender, or indeed that the message hasn't been altered.
Well, I'm sorry, but if you're encrypting it, what exactly is the purpose of including the hash? If it's encrypted, then it can't be tampered with anyway (assuming that your algorithm-of-choice hasn't been broken yet).
Re:And they scoffed at my continued reliance on MD
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That's supposed to be 2^69. Now, 269 -- that would be a story!
Re:And they scoffed at my continued reliance on MD
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Uh, it still requires 269 operations. But I can't seem to find out how that compares to MD5 breakage.
Re:May be a big deal...
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Actually, that wouldn't really work in practice. What would stop someone from intercepting it and changing the message and the hash before your receive it?
I think what you are thinking of is a digital signature system, where the document is hashed and then the hash is signed. Any tampering would invalidate the signature. The hash is used because it takes a lot of random data to encrypt an arbitrary file, while it takes quite a bit less to encrypt a short, fixed-length hash like SHA-1. Since (in theory), the probability of message collision is quite low, the hash is (practically) as good as the real thing for signing.
Re:Yeah...
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Well, no. Not exactly. SHA-1 is supposed to be a one-way function, meaning that you can't just reverse the operation. So you can't just "crack" it like solving an equation.
I'm not sure if you are talking about retrieving the original file from the hash, but if you are, then you don't understand what hash functions are for. In this case, there are an infinite number of combinations of bytes that have the same SHA-1 hash. The goal is to find one that has the same hash value, regardless of whether it is actually the same file. SHA-1 is not a cipher.
That headline seems to imply that the act is ineffective, not that it has caused an increase of spam. The worst thing that headline might be guilty of is a mixed metaphor.
I guess you missed this: "Still, Cooper said he expected Microsoft to eventually cut off that security update avenue for pirated copies. He said the company may feel it has few other options as it tries to stop the millions of users who are running pirated copes of Windows.".
What happens when all of those pirate systems get exploited because they can't get their security updates? Of course, I wouldn't be surprised if most of them remain unpatched today.
What about the Microsoft security initiative? Is that being bested by the Microsoft why-aren't-you-getting-the-money initiative?
From the summary: The global warming danger threshold for the world is clearly marked for the first time in an international report to be published tomorrow...
I guess you've never had to fill out a U.S. Customs and Border Protection Declaration Form 6059B. Item 4 asks for "U.S. Street Address (hotel name/destination)." Either that or the customs official didn't bother to ask for details.
I understand that you could easily fabricate some information that they would accept, but I try to avoid lying--I'm not very good at it.
Smithers, I've designed a new airplane. I call it the "Spruce Moose", and it will carry two hundred passengers from New York's Idyllwild Airport to the Belgian Congo in seventeen minutes!
Slashdot Mirror
So if you emptied the whole AC, then emissions wouldn't be a problem here. Of course, Europe and Asia would get much worse!
That depends on how you eliminate the American population. Soylent green, anybody?
Who said anything about computers? Hash functions are perfectly valid outside of the context of electronic systems.
It is perfectly possible to deterministically alter an encrypted message.
Sure, but how does including the hash prevent that from working? That is why you would use a digital signature system as I said in my other message. A hash by itself is worthless for verifying the sender of the message. As I said, a hash is typically part of a digital signature system, but by itself it does nothing to verify the identity of the sender, or indeed that the message hasn't been altered.
Well, I'm sorry, but if you're encrypting it, what exactly is the purpose of including the hash? If it's encrypted, then it can't be tampered with anyway (assuming that your algorithm-of-choice hasn't been broken yet).
That's supposed to be 2^69. Now, 269 -- that would be a story!
Uh, it still requires 269 operations. But I can't seem to find out how that compares to MD5 breakage.
Actually, that wouldn't really work in practice. What would stop someone from intercepting it and changing the message and the hash before your receive it?
I think what you are thinking of is a digital signature system, where the document is hashed and then the hash is signed. Any tampering would invalidate the signature. The hash is used because it takes a lot of random data to encrypt an arbitrary file, while it takes quite a bit less to encrypt a short, fixed-length hash like SHA-1. Since (in theory), the probability of message collision is quite low, the hash is (practically) as good as the real thing for signing.
Well, no. Not exactly. SHA-1 is supposed to be a one-way function, meaning that you can't just reverse the operation. So you can't just "crack" it like solving an equation.
I'm not sure if you are talking about retrieving the original file from the hash, but if you are, then you don't understand what hash functions are for. In this case, there are an infinite number of combinations of bytes that have the same SHA-1 hash. The goal is to find one that has the same hash value, regardless of whether it is actually the same file. SHA-1 is not a cipher.
Sylpheed-claws uses dillo. At least, my version does.
Best. Comment. Ever.
I can't remember the last time I actually laughed out loud at Slashdot.
Well, I guess this will make my grocery shopping simpler.
!seineew era sreenigne epacsteN
"This link lets you experience the moon just as the Apollo missions' astronauts did..."
/. effect so effortlessly.
I didn't realize that accessing the moon was such a slow process. Kudos to the Apollo astronauts for putting up with the
Shouldn't those spare cycles be used to wget pr0n?
That headline seems to imply that the act is ineffective, not that it has caused an increase of spam. The worst thing that headline might be guilty of is a mixed metaphor.
That's a problem with the media, not the judicial system.
Like this one? $2 at Taco Bell.
I guess you missed this: "Still, Cooper said he expected Microsoft to eventually cut off that security update avenue for pirated copies. He said the company may feel it has few other options as it tries to stop the millions of users who are running pirated copes of Windows.".
What happens when all of those pirate systems get exploited because they can't get their security updates? Of course, I wouldn't be surprised if most of them remain unpatched today.
What about the Microsoft security initiative? Is that being bested by the Microsoft why-aren't-you-getting-the-money initiative?
Does anyone have a link to the actual report?
...
From the summary: The global warming danger threshold for the world is clearly marked for the first time in an international report to be published tomorrow
I guess you've never had to fill out a U.S. Customs and Border Protection Declaration Form 6059B. Item 4 asks for "U.S. Street Address (hotel name/destination)." Either that or the customs official didn't bother to ask for details.
I understand that you could easily fabricate some information that they would accept, but I try to avoid lying--I'm not very good at it.
Smithers, I've designed a new airplane. I call it the "Spruce Moose", and it will carry two hundred passengers from New York's Idyllwild Airport to the Belgian Congo in seventeen minutes!
Also, Irving, California should be the more well-known Irvine, California
Forget that! I want a tinfoil suppression shield! If it works for the satellite it should do just fine for me.
Okay, the post isn't funny, but the T-shirt is hilarious!