Thorham

I think I'll stick to hexadecimal notation.

(2^32)-1, sorry. No, that's not a problem, because XOR shift isn't a cryptographic PRNG. I used this as an example for something. I also said it's not cryptographic. In AES-CTR mode AES is used as a block cypher. It's output is simply XORed over the plain text. So, yes, it's just XOR, because nothing else is done with the plain text. This, in fact, creates a weakness to tampering: If I change bit 123 in the cypher text, then bit 123 will also be changed in the plain text once the data has been decrypted. It's just XOR. I never said you should use time as a key

Actually, it is, because the key functions as the crypto PRNGs seed. For example, with AES-CTR you encrypt a nonce and a counter, the resulting block is XORed over a plaintext block. One AES block is 16 bytes. 12 of those are used for the nonce, the remaining four for the block counter. The seed is now a combination of the encryption key, the nonce and the counter. Since the nonce and counter are known, stealing the unknown part of the seed is the same as stealing the key. Yes, but not the key. The key length isn't relevant for the length of the pseudo random sequence. The length of the sequence depends on the algorithm that's used and the size of the internal state of the generator. For example, the non-cryptographic PRNG 32 bit XOR shift has an internal state of 32 bits, and a seed size of 32 bits (seed is state in this case). The length of the sequence is 2^32-1 32 bit numbers (all unique). Of course, but in practice you'd use a proper encryption key (with salt), and the time stamp may be safe to use as a nonce. The seed is now made up of a salted key and a nonce. The nonce is known, but the key isn't. Any very weak, unsalted key has a good probability of being guessed. Indeed.

No. It depends on the system. In situations where the clock can't be set by some external means using a time stamp as a nonce is fine. You shouldn't see everything so black and white, and instead look at a crypto system's requirements, which will partially depend on the system it has to run on. So, basically you're saying that every block cipher is completely broken? Do you have any proof for this? It's absolutely astonishing that you still refuse to see the point. I gave an example of how you can construct a nonce for AES-CTR. I used a time stamp in the example to show that the nonce only has to be unique. That was the whole point of the example. That the security of using a time stamp as a nonce depends on certain factors isn't relevant (it can, of course, be secure, but that wasn't the point). Nowhere did I recommend using time stamps as a nonce for AES-CTR. I said that you could, because for AES-CTR a nonce only needs to be unique for each file you encrypt with the same key. That this is only a good idea in certain specific system setups is blatantly obvious. You've also mentioned several times that you shouldn't use PRNGs for encryption. Why? What's so bad about using cryptographic PRNGs? Stealing the seed means that you're stealing the encryption key. As for guessing it, good luck with that, unless someone used a weak key without a salt. Doesn't matter though. Secure cryptographic PRNGs have to be brute forced, or in the best case you can do a little bit better than that. Not practical.

I wasn't talking about a random source, I was giving an example of nonce generation to show that it doesn't matter what the nonce actually is. In practice there are obviously situations where using a datestamp as a nonce is completely safe. However, and I must stress this, you fail to see that it was an example of how a nonce can by anything as long as it's unique for a particular key. You've basically missed the point entirely. This is nonsense. There is no problem with XOR and there's no problem with good cryptographic PRNGs. Where did you even get this from?

I wasn't talking about salts, I was talking about nonces. These two things are completely different. Only if your system is utterly broken, of course. Here you come with salts again. Do you even know what a salt is? Not necessarily for something that only needs to be unique and will be known by everyone. It was also just an example of how it doesn't matter what a nonce (NOT salt!!!) actually is, and that the only requirement is uniqueness. Nonsense. Any cryptographically strong PRNG can be used for encryption. The problem isn't with XOR.

In which case we wouldn't be able to worry about it. I originally said that we do what we do because we see ourselves as more important than other species. Not nearly enough. Instead of being cruel, we try to be a little bit less cruel. I say that because I mean it, and I really don't sit in guilt waiting for some cataclysm to occur. That's one of the very last things I want. Really. If everything is natural, then the word looses it's meaning. In my opinion, everything that's created through some sort of cognitive process is unnatural. A beaver's dam, a bird's nest or a human's computer, all unnatural. Does it matter? No. I don't care about what's natural and unnatural. It's entirely irrelevant to me. It's quite the opposite. Admitting to wrongdoing is an important step. Open your eyes. A non-human life is worth Jack S, and I'm eternally grateful that I'm a human seeing how I was born on this planet. This is the world we live in and denying it is simply wrong. It's about brutal honesty here. I don't feel humans in general are horrible, I just see that we do bad things. When you look at this world, can you not see this?

My viewpoint has absolutely nothing to do with emotion at all (even if it did, would that be a bad thing?). We use all of this world and everything that lives on it for our own purposes and don't give a damn about the creatures we abuse. This is a simple fact. How is this not obvious? No. I said that we could live like that, not that we should. Personally I'd sooner hang myself than live like that. I never said anything of the sort. I also have absolutely no problem with unnatural things at all. Where did I even say I did? And it seems like you have absolutely no clue of what I was talking about. Which is a fine justification to do what ever the hell we want, isn't it? At least I admit that I do it and have no intention to stop doing it. Yes, and we'll brutally torture and kill countless beings to create these medicines which I too would gladly use if I had to. Come on people, just admit the damned truth. And no, it's not meant to make anyone feel guilty or bad. It's just the way things are.

Bull. It's exclusively about our importance. We could just be surviving in the wild, and do just fine. No medicine, no science, no technology. In the greater scheme of things it matters nothing. It matters to us, though. Perfectly understandable. I don't want to live like that. You don't want to live like that. Most people don't. Don't pretend that it's about anything else. Anything beyond survival is just luxury, and we don't need most things to survive. My response isn't emotional (emotional beings reacting emotionally, imagine that!), I'm simply stating the way things are.

Animal testing is done because humans see themselves as more important than other species. Everything we use non-human animal species for we only do because we see ourselves as more important than them. It's nothing but egotistical garbage. And yes, I'm a hypocrite, I realize that all too well

That kind of thing depends on how you construct your cryptosystem. An example of a setup that doesn't do this is AES-CTR. This encrypts a 16 byte counter + nonce (you can combine a 12 byte nonce and a 4 byte counter) using the encryption key, and XORs the resulting data over the plain text to create the cypher text. The only thing you have to do is make sure that the nonce is unique for each message that is encrypted with the same key. The nonce can literally be anything. Even a time stamp will suffice. The only requirement is uniqueness. It doesn't have to be secret, either, and is actually included in the ciphertext for all to see. It's much more important to make sure that your system is complete and well implemented (the actual encryption is the easy part). What's lacking in the above setup is an authentication method that prevents attackers from changing the encrypted message. A hard requirement for any psuedo random number generator used for encryption is that it's a strong cryptographic PRNG. AES-CTR qualifies as one. There are others, of course. What you're describing is only possible with weak generators, or generators that aren't cryptographic, such as Mersenne Twister or XORShift. The problem isn't XOR. The strenght of a cryptosystem depends on multiple factors. What you XOR over the plaintext is one factor. How you generate what you XOR over the plaintext is another factor. If what you XOR over the plaintext is cryptographically strong and generated in the right way, then that part of the cryptosystem is sound (as far as encrypting the data goes, there's still the implementation to worry about, because of side channel attacks).

That's not true. XOR can be used to mix plain text with the output of a stream cipher (cryptographically secure PRNG). One time pads are in no way a requirement. Standard cryptography uses XOR all the time.

Yes, and that's another problem for me. Science can't answer certain questions, including the ultimate question, namely: What is the true nature of reality? So I'm going to stick to programming. Much easier

The point is that I thought you meant the subjective tall, which depends on your viewpoint, while length does not, because it depends on some reference unit. That's probably easier than counting atoms Right, but what causes the charge? Is it simply part of the way a particle behaves? Impossible to prove. That's the problem with that wall. Is there nothing more? Perhaps there is, but can we get to it? If we can get to it, how hard is that going to be? Is it going to take 10 years? A 100? A million? Anyway, I should know better than to start arguing about physics, and from now on I'm going to stick to something I know: Computer programming.

Right, you mean length. Thought you meant the subjective tall (I'm tall compared to a mouse, but short compared to an elephant). Asking what length is, is valid. For items made of atoms, it's more or less the number of atoms along a straight line between the two measuring points... or something like that The involved 'stuff' is atoms. In the case of electric charge, it's an abundance or shortage/absence of electrons. Here the 'stuff' that's involved is electrons. Now, how do we answer this for magnetism? What's the involved 'stuff' here? Perhaps, but what if some of those questions can be answered? You're obviously (probably) going to hit a wall at some point. A point where you can't go farther because nature won't let you, or because you've simply arrived at the end. Until that happens, these questions must be asked.

Charge and tall aren't the same kind of property. Charge is a physical property that can be measured, while tall is a subjective property that can't be measured. The fact that charge can be measured makes the question 'What is it?' completely valid. At the most fundamental level you can ask that question about anything. What's a photon? Photons are fundamental particles, right? From what I understand about this it means that they aren't made of smaller particles. The question is whether or not that means that they aren't made of anything and simply are ('made' of themselves, so to speak). Then there's also the possibility that they are made of something, just not particles, and not something that we could hope to measure right now. Could take ten thousand years to discover that, for all we know. Or it's not possible for us to measure this if it's so. Asking what something is, is completely valid.

Depends entirely on what you XOR over your plain text. There's also the construction of your cryptographic system as a whole to consider. Your best bet is to check out http://crypto.stackexchange.com/ and look for AES encryption. Very good place to ask encryption related questions, and you're going to need it, because encryption is very tricky business.

And a thousand years ago we had no evidence that protons are made of anything. We didn't even have evidence for the protons themselves. Asking what something is made of is still a valid question.

Bytes weren't always fixed in size in the past.

In this case, the 16 bit number is added to a pointer to form a new pointer. The 16 bit number itself is not an address. Think of it as an index. The 16 bit value isn't really an addres, but a number that's added to an address to form a new address. Not exactly. Addresses are always positive values. The values that get added to addresses don't have to be positive. If you have address 100000, then it's no problem to subtract 32000 from it. Most CPUs out there use 8bit bytes.

No, it's not saying that, it's saying that with a 16 bit value you can address 65536 bytes. Here's an example: You have a pointer A, and the signed 16 bit value they're talking about in the book. We'll call that B. What you can do now, is use an addressing mode that adds A and B together, and uses the end result as a new pointer. Say A = 100000, and B = 30000. The resulting pointer would be 130000. If B would be -30000, then the resulting pointer would be 70000. The signed 16 bit range is -2^15 to 2^15-1. Example in Motorola 68000 assembly language: lea 100000,a0 ; set the pointer to 100000 move.w #30000,d0 ; set the signed value to 30000 move.b #123,(a0,d0.w) ; add ponter and signed value together ; to form a new pointer, which points to ; 130000, and write the value ; 123 to that location

It's not a property at all. Color is a mental representation of the frequencies of visible light.

Are you serious? Someone who helps and cares for people is no better than a psychopath? How good one is depends on the amount of pleasure in their life? Really? You call youself less than Shitler because you have less pleasure than he had? You have some very serious issues, and need to seek proffessional help.

Well, at least it's over

I really couldn't care less.