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location Wellington, New Zealand
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visits member for 2 years, 6 months
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I am an undergraduate computer science and mathematics student in New Zealand. My fields of interest are computer graphics, in particular the physics of light transport, and to some extent cryptography, as well as programming and software development in general.


Jan
23
comment Question about SHA-2 (and potentially similar hashing algorithms)
If the constants were not constant, you could not use the hash function without keying it, so it would not be a hash function but something else. You can read up on en.wikipedia.org/wiki/Nothing_up_my_sleeve_number
Jan
20
revised Low Public Exponent Attack for RSA
added 238 characters in body
Jan
20
comment Is SHA-256 safe when used in this way?
@StephenTouset Your point is valid, but I think the question here is "assuming TXT cannot be brute-forced, does having multiple hashes of TXT | N help recover it faster".
Jan
19
reviewed Approve suggested edit on Low Public Exponent Attack for RSA
Jan
13
comment Chance in cryptography
Why do you feel that it is a problem? The solution crypto gives to this issue is simply lowering the probability enough (in a measurable and concrete way) to be deemed negligible. Again, just because a probability is not zero doesn't mean it's going to happen.
Jan
12
comment Why is the discrete logarithm problem assumed to be hard?
$O(n)$ is polynomial in the order of the group, in general polynomial-time means polynomial in the number of digits thereof, i.e. $O(\log^k(n))$. This is because we can make $n$ rather large easily (a few hundred digits), but making $\log(n)$ large is "much harder".
Jan
11
comment Cryptographically secure product keys
Have you considered the option of simply storing assigned product keys on the server securely?
Jan
10
reviewed Approve suggested edit on
Jan
10
reviewed Approve suggested edit on
Jan
10
revised ECDSA vs ECIES vs ECDH
proper abbreviations, and fixed some grammar/spelling
Jan
10
comment Are the SHA family hash outputs practically random?
If some characters were consistently less "random" than others that would indicate a severe flaw in the hash function.
Jan
6
answered How does Clifford Cocks 'Non-Secret Encryption' work?
Jan
5
reviewed Approve suggested edit on How can I solve congruence modulo N?
Jan
5
comment Is differential calculus related to RSA?
Every part of math is related to any other if you try hard enough.
Dec
22
comment Is a Mersenne-twister cryptographically secure if I truncate the output?
But again, if you think you know everything and are always right, go right ahead, no one can stop you. If you implement this, and your game becomes popular, and eventually someone discovers this, exploits it, and steals a bunch of money, you're going to have a hell of a time defending why you deviated from industry standards, tried to do better than everyone else, and lost. In fact this thread may even serve as evidence. And, yes, this does happen, very often. Good luck with your project.
Dec
22
comment Is a Mersenne-twister cryptographically secure if I truncate the output?
It's regrettable that the question as-is seems to imply that it's OK to do whatever the OP suggested. A shame for future visitors who may not have the insight of actually checking the rest of the thread, and end up using a homebrewed, brittle, and perhaps profoundly insecure PRNG as though it were a CSPRNG. I also like that you dismiss the entire field of cryptanalysis as if you were too good for it and just assume all your arguments are correct. Seriously, it's cool to be creative for experiments, but for a real project, no less an ONLINE CASINO GAME, you WANT to use best practices. NOT THIS.
Dec
22
awarded  Informed
Dec
21
comment How can uniformity of hash functions (e.g. SHA-256) be proved?
I'll leave it to someone else to write up a formal answer but I believe the short answer is that there is no proof. One can sort of offer mathematical arguments that SHA-256 is secure against such and such attack, or has such and such general property, but by and large it's just a matter of cryptographers around the world banging as hard as they can on it and seeing it if breaks. Symmetric cryptography is nothing like number-theoretic crypto which is much bigger on actual proofs (cf. factorization, DLP, DDH, ..)
Dec
21
comment Calculate entropy of key derived from PBKF2 function
@deltaaruna The salt is not (intended to be) secret, so it has zero entropy. The password has entropy $e$, and you use $2^k$ rounds - so the total amount of "work" in the computational sense to brute force the password is on the order of $2^k 2^e = 2^{k + e}$, so the "entropy" is $k + e$ (again, in the computational sense - the information-theoretical entropy of the key is at most the entropy of its inputs, but since it takes more work to verify your guess you can think of it as "extra passwords to check", e.g. 2 iterations = twice as many passwords to check computationally = +1 bit entropy).
Dec
20
comment Calculate entropy of key derived from PBKF2 function
(up to a maximum of the output length specified to the PBKDF2 algorithm)