I actually prefer "if (!ptr)" to "if (ptr == NULL)", for two reasons
Thats one of the things I've yet to grasp when it comes to C. In Delphi we have a function called Assigned() which, you might have guessed it, returns true if the pointer is not NULL (or nil in pascal), false otherwise. Why isn't such a macro baked into the some common framework, or why doesn't more people use such a macro?
if (assigned(p))
foo(p);
seems pretty clear to me.
Re:does anyone actually use either md5 or sha-1...
on
SHA-1 Broken
·
· Score: 1
Seriously... I don't even use them for hashing my passwords any more. Now it's BFS (blowfish) and AES.
You are clearly more experienced in this area than I am; this was probably a bad example. Forget I mentioned initial jpeg compression. (Though perhaps in rapid display of jpegs such as an iPhoto slideshow or screensaver the lossiness would be more acceptable.
Didn't mean to sound terse, just trying to point out that "all losses are not equal", or something like that. However, like you suggest, I can see that for very specific domains it can be usefull. (For rapid display of jpeg though there's a smarter way: Don't decode all the information. Only decode 2x2 of the coefficients or even less).
Just because JPEG is lossy does not mean it can be encoded using "lossy" circuits. The reason it is lossy is the same as if you were to store a 24 bit image using 16 bits. However, the way it does this and stores the image is NOT fault tolerant. Disregarding the huffman compression (which must be coded/decoded using exact circuits), a slightly wrong value in one of the coefficients can result in an entire 8x8 block of wrong color.
The company I work for has a password policy like this:
1. Must contain at least 8 characters 2. Must contain at least 2 lowercase letters 3. Must contain at least 2 capital letters 4. Must contain at least 2 numbers
Hah, thats nothing! The company I work for requires that the password is at least 18770 characters long and not any of my previous 30689 passwords! How's that for Windows security?!
The Government uses these devices to ensure that the password entered, is only the person who has the number generating device in their hand. I'm not sure of any ways to defeat this kind of security, although I'm sure it exists...
I imagine that you could perform a statistical attack if you snoop up enough numbers over time. However I think that's beyond the scope of most spyware-criminals. I bet it's easier to find a hole in the authentication code on the server, or otherwise hack your way into the server.
All a computer needs is a little spyware, and presto, 128bit encryption is rendered useless.
My bank issued me a small "calculator", where I punch in a 4 digit pin number, and if correct prints a (changing) 6 digit number. When logging in, I punch the first 4 of the digits along with my login id, and the following page then states what the last two digits should be. That way I know I'm talking with my bank. The code used is then no longer valid, ie next to useless to a spyware program.
From what I can think of, the spyware would have to utilize the current browser session, as a new window = new login, and they don't have access to my "calculator".
Sounds quite a bit safer than certain other methods I've seen, but then I'm by no means an expert at this field.
One question might be...why write the data directly to a database initially? Why not utilize a faster format, then write to the DB when things have slowed down (i.e. caching)?
From what I understood, thats the point. Except you never write to the DB. Instead of reading from the socket, storing in memory buffer, then performing filtering, you filter directly the data you're reading from the socket. No need to store in memory first!
I do, yes. But as I pointed out previously, most people won't know how to, and even if they do, Microsoft are bitchy about supporting systems where you've moved key folders like this, with dire warnings all over MSDN about not doing it.
And the big reason NOT to back up your system partition is... ?
If you don't know how to move the folder, at least back up the partition its on (I'd do that anyway, as many fun things are stored in the %SystemRoot%).
The official story is that the language Delphi-the-ide used was always called Delphi. However that fact wasn't communicated to the people who wrote the documentation and similar. Many still prefer to call it Object Pascal though.
This has been discussed at lengths in the newsgroups.
What does that even mean? I know it's from Star Wars, but a parsec is a unit of distance, not time.
AFAIK the kessel run involved a black hole intersecting the flightpath. So the closer you managed to travel to the hole, the less distance you'd have to travel in total.
If the postage is 20 bits, then that's only a search space of 1 million. Just precompute them all (would take less than 12 CPU-days) and you can answer any question in O(1).
The way I read it, the postage is the number of leading zero bits in an SHA1 hash, which is 160 bits long. In addition, the recipients email address is part of the string to be hashed, so I don't quite see how they can precompute this into a lookup-table.
If you're only using a subset of the hash space, store the results of each hash you try. Then, the next time around, finding the result is near instantaneous... Making the scheme innefective.
If you read the article, you'll find that:
The source string for the hash is your email + suffix. The sender has to find a suffix which will make a "valid" hash. Thus a sender can't use the same hash for multiple recipients.
Recipients will want to store received hashes, to ensure that the same hash isn't used twice (at least for a period of time).
what are the thoughts of someone who doesn't know a language like?
Reminds me about an article I read in SciAm or American Scientist some time ago. Some scientists had performed an experiment with kids at an early age (I can't remember the specific age, around 1 year I think). They had taught the kids a simple ball game. The kids had at that point not learned the proper word for "ball" etc.
A year later the scientists visited again, and asked if the kids could describe the game for them. They found that while the kids had aquired the neccessary vocabulary during that year to fully describe the game, most kids would not use any of the "new" words in their description. Instead they would use only the vocabulary they had at the point they learned the game.
The article concluded that this indicated that memory is formed using the language you know at the time. Which my dad found interesting. He used to teach Norwegian to refugees. In his experience, refugees who only received training in Norwegian and not in their native language tended to lose their native language and if that happened, they also had problems recollecting things that had happened before they arrived.
As for how one thinks without language. I don't think I could convey the feeling of my girlfriends hands running gently down my back to someone who had never expeirenced it, in a way that made him able to truly imagine how it would be like. Yet I have no problems thinking about it. I guess it would be somewhat similar.
What kills non-IE browsers in the eyes of Joe Sixpack is that they don't render things 100% like IE.
Dude, not even IE renders 100% like IE! And I'm not talking IE 3.x vs IE 6.0.
I just found out that my page looks like a trainwreck on IE 6.0.2900 (xp sp2). Since I'm still using 6.0.2800 (xp sp1), I didn't know anything was up, since it looks perfect on it (even looks identical to FireFox)!
So, what was the problem again?
(for what it matters, its 100% valid 4.01 strict + css)
So, the bitrate increases to something like 8192.08 bit/s. And that's all that's needed to make the subsequent circuit choke and lose half the data?
Well, the article states
In effect, the [Doppler] shift would push the signal out of synch with the timing scheme used to recover data from the phase-modulated carrier.
The problem is the timing needed to detect the phase changes, not handling slightly more bits per second. This is mentioned in the slide here which illustrates the technique used.
Ok I admit I don't know a lot about voting systems around the world, but the one we have in Norway seems to me to be less error prone than punching holes in a card. Here we have one card per party. Each card has the name of the party clearly marked on the top, and the names of the candidates for that party. If you're "pro" you can give additional votes to certain candidates and such (doing this wrong can easily invalidate your vote), but for a plain vote, take the card and put it into the envelope. Only way to screw up is to put multiple cards into the envelope. These cards also have bar codes on them, which allows them to be machine read.
Re:Can we PLEASE STOP linking to this guy's blog??
on
Jet Engine on a Chip
·
· Score: 1
In all seriousness, why does/. continue to link to his ramblings instead of to articles that contain real, useful, technical content?
Cause they did? Or did you completely miss the first link in the story?
Yes, this is probably off-topic (as in "not about tiny turbines") but it is still relevant. At least give us the option to ignore him.
And just how did any slashdot editor FORCE you to click on the second link? I'm curious. Do they stand behind your back or something?
Slashdot Mirror
As a cyclist, I'm not required to have a drivers license. So, why ask for it?
Perhaps to get your name correct? Much quicker to read some card than to have you spell it out (in case you got a "weird" name).
Thats one of the things I've yet to grasp when it comes to C. In Delphi we have a function called Assigned() which, you might have guessed it, returns true if the pointer is not NULL (or nil in pascal), false otherwise. Why isn't such a macro baked into the some common framework, or why doesn't more people use such a macro?seems pretty clear to me.
Seriously... I don't even use them for hashing my passwords any more. Now it's BFS (blowfish) and AES.
And how do you use AES for hashing?
You are clearly more experienced in this area than I am; this was probably a bad example. Forget I mentioned initial jpeg compression. (Though perhaps in rapid display of jpegs such as an iPhoto slideshow or screensaver the lossiness would be more acceptable.
Didn't mean to sound terse, just trying to point out that "all losses are not equal", or something like that. However, like you suggest, I can see that for very specific domains it can be usefull. (For rapid display of jpeg though there's a smarter way: Don't decode all the information. Only decode 2x2 of the coefficients or even less).
the initial JPEG lossy compression
Just because JPEG is lossy does not mean it can be encoded using "lossy" circuits. The reason it is lossy is the same as if you were to store a 24 bit image using 16 bits. However, the way it does this and stores the image is NOT fault tolerant.
Disregarding the huffman compression (which must be coded/decoded using exact circuits), a slightly wrong value in one of the coefficients can result in an entire 8x8 block of wrong color.
The company I work for has a password policy like this:
1. Must contain at least 8 characters
2. Must contain at least 2 lowercase letters
3. Must contain at least 2 capital letters
4. Must contain at least 2 numbers
Hah, thats nothing! The company I work for requires that the password is at least 18770 characters long and not any of my previous 30689 passwords! How's that for Windows security?!
The Government uses these devices to ensure that the password entered, is only the person who has the number generating device in their hand. I'm not sure of any ways to defeat this kind of security, although I'm sure it exists...
I imagine that you could perform a statistical attack if you snoop up enough numbers over time. However I think that's beyond the scope of most spyware-criminals. I bet it's easier to find a hole in the authentication code on the server, or otherwise hack your way into the server.
All a computer needs is a little spyware, and presto, 128bit encryption is rendered useless.
My bank issued me a small "calculator", where I punch in a 4 digit pin number, and if correct prints a (changing) 6 digit number. When logging in, I punch the first 4 of the digits along with my login id, and the following page then states what the last two digits should be. That way I know I'm talking with my bank. The code used is then no longer valid, ie next to useless to a spyware program.
From what I can think of, the spyware would have to utilize the current browser session, as a new window = new login, and they don't have access to my "calculator".
Sounds quite a bit safer than certain other methods I've seen, but then I'm by no means an expert at this field.
One question might be...why write the data directly to a database initially? Why not utilize a faster format, then write to the DB when things have slowed down (i.e. caching)?
From what I understood, thats the point. Except you never write to the DB. Instead of reading from the socket, storing in memory buffer, then performing filtering, you filter directly the data you're reading from the socket. No need to store in memory first!
It has the aura of sexiness about it, though, which has attracted a lot of bright physicists, but it's got a gaping hole.
Certain other circles I know about, this would be considered _very_ hot indeed.
I think it's about time someone came up with an easier way to upgrade php.
I found it very easy and quick. Stop apache. "emerge mod_php". Wait oh, 5-10 mins. Start apache.
Perhaps I missed something?
Porn on your cell phone.
Should be a hit among those with inferiority complex
I do, yes. But as I pointed out previously, most people won't know how to, and even if they do, Microsoft are bitchy about supporting systems where you've moved key folders like this, with dire warnings all over MSDN about not doing it.
And the big reason NOT to back up your system partition is... ?
If you don't know how to move the folder, at least back up the partition its on (I'd do that anyway, as many fun things are stored in the %SystemRoot%).
I do, however, want all of my essential data to be stored on my RAIDed, routinely backed-up hard drive.
:)
And you don't keep your Documents and Settings folder on the disk that is beeing backed up? I guess you don't have much to lose then
I usually move my Documents and Settings folder to a nother disk right after install, much easier than to do it later.
The cheating via SMS
I'm so glad my gf doesn't read slashdot, or I'd have another thing to worry about!
it's an IDE. Delphi uses Pascal
The official story is that the language Delphi-the-ide used was always called Delphi. However that fact wasn't communicated to the people who wrote the documentation and similar. Many still prefer to call it Object Pascal though.
This has been discussed at lengths in the newsgroups.
What does that even mean? I know it's from Star Wars, but a parsec is a unit of distance, not time.
AFAIK the kessel run involved a black hole intersecting the flightpath. So the closer you managed to travel to the hole, the less distance you'd have to travel in total.
If the postage is 20 bits, then that's only a search space of 1 million. Just precompute them all (would take less than 12 CPU-days) and you can answer any question in O(1).
The way I read it, the postage is the number of leading zero bits in an SHA1 hash, which is 160 bits long. In addition, the recipients email address is part of the string to be hashed, so I don't quite see how they can precompute this into a lookup-table.
If you read the article, you'll find that:
what are the thoughts of someone who doesn't know a language like?
Reminds me about an article I read in SciAm or American Scientist some time ago. Some scientists had performed an experiment with kids at an early age (I can't remember the specific age, around 1 year I think). They had taught the kids a simple ball game. The kids had at that point not learned the proper word for "ball" etc.
A year later the scientists visited again, and asked if the kids could describe the game for them. They found that while the kids had aquired the neccessary vocabulary during that year to fully describe the game, most kids would not use any of the "new" words in their description. Instead they would use only the vocabulary they had at the point they learned the game.
The article concluded that this indicated that memory is formed using the language you know at the time. Which my dad found interesting. He used to teach Norwegian to refugees. In his experience, refugees who only received training in Norwegian and not in their native language tended to lose their native language and if that happened, they also had problems recollecting things that had happened before they arrived.
As for how one thinks without language. I don't think I could convey the feeling of my girlfriends hands running gently down my back to someone who had never expeirenced it, in a way that made him able to truly imagine how it would be like. Yet I have no problems thinking about it. I guess it would be somewhat similar.
What kills non-IE browsers in the eyes of Joe Sixpack is that they don't render things 100% like IE.
Dude, not even IE renders 100% like IE! And I'm not talking IE 3.x vs IE 6.0.
I just found out that my page looks like a trainwreck on IE 6.0.2900 (xp sp2). Since I'm still using 6.0.2800 (xp sp1), I didn't know anything was up, since it looks perfect on it (even looks identical to FireFox)!
So, what was the problem again?
(for what it matters, its 100% valid 4.01 strict + css)
Well, the article states
The problem is the timing needed to detect the phase changes, not handling slightly more bits per second. This is mentioned in the slide here which illustrates the technique used.
Ok I admit I don't know a lot about voting systems around the world, but the one we have in Norway seems to me to be less error prone than punching holes in a card.
Here we have one card per party. Each card has the name of the party clearly marked on the top, and the names of the candidates for that party. If you're "pro" you can give additional votes to certain candidates and such (doing this wrong can easily invalidate your vote), but for a plain vote, take the card and put it into the envelope. Only way to screw up is to put multiple cards into the envelope.
These cards also have bar codes on them, which allows them to be machine read.
In all seriousness, why does /. continue to link to his ramblings instead of to articles that contain real, useful, technical content?
Cause they did? Or did you completely miss the first link in the story?
Yes, this is probably off-topic (as in "not about tiny turbines") but it is still relevant. At least give us the option to ignore him.
And just how did any slashdot editor FORCE you to click on the second link? I'm curious. Do they stand behind your back or something?
Why do buses and trains hiss?
Afaik, they use compressed air for breaking. As in, they use compressed air to keep the brakes away from the disk.