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visits member for 2 years, 10 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.


Jul
4
reviewed Approve suggested edit on padding-oracle tag wiki excerpt
Jul
4
reviewed Approve suggested edit on length-extension tag wiki
Jul
4
reviewed Approve suggested edit on padding-oracle tag wiki
Jul
4
comment Cryptographic Challenge: How to Say Something Confidentially to Snowden?
Isn't objective #2 self-contradictory?
Jul
3
comment constructing QR-like one way function
I think you made a mistake, $x^2 \mod p$ is not (generally) one-way, there are efficient algorithms to take modular square roots modulo prime numbers (it's much harder for composites, though). Did you mean $a^{\frac{p - 1}{2}} = \binom{a}{p}$ which then obviously lacks collision resistance..
Jun
30
comment Why is “mod(n)” so central to most aspects of cryptography?
@nightcracker Unless you count bitwise modulo's, which are still there but just hidden and implied :p (though I agree with you that symmetric cryptography doesn't need as much number-theoretic baggage - it just needs to be able to throw bits around efficiently)
Jun
30
revised Integer factorization via geometric mean problem
added 546 characters in body
Jun
30
answered Integer factorization via geometric mean problem
Jun
30
comment Integer factorization via geometric mean problem
What makes you think that arbitrarily truncating $\sqrt{c} \times 10^i$ for any $i$ will give a meaningful integer with the properties you describe? The reason it works for small numbers is that some $i$ ends up giving a factor by chance, obviously that doesn't happen for larger integers. I don't follow your geometric mean argument - how does it relate to multiplying the mean by a power of 10? Why not a power of 2? What's so special about 10? (I think this is where your argument breaks down - $g$ is irrational so you'll never get an integer, perhaps you were thinking of continued fractions?)
Jun
29
comment Proof of work for determining whether a number is prime?
Why not select the primes yourself and create a challenge using that? That way it would be trivial for you to verify if there is (at least) a prime falling inside a given range. Or is this a distributed proof of work scheme?
Jun
24
comment Map Bytes to Number
A more efficient approach is to take the problem modulo 65536 and divide by 6 when less than 60000, you will waste less entropy this way. This question is actually a duplicate of a couple crypto.SE questions, in particular crypto.stackexchange.com/questions/5708/… and crypto.stackexchange.com/questions/6175/…
Jun
24
reviewed Satisfactory Polynomial multiplication and division in2^128
Jun
24
reviewed Satisfactory Is Base64(SHA1(GUID)) still unique like the original GUID?
Jun
24
reviewed Excellent AES plaintext is smaller than 128 bits - how to expand?
Jun
24
reviewed Satisfactory How does the birthday attack work in AUTH and UF-CMA games?
Jun
24
reviewed Satisfactory Injecting salt into PyCrypto KDF - useful?
Jun
24
comment If we can find prime numbers larger than 17 milion digits, why can't we find all 1024bit primes?
@user129789 Those numbers are so huge that no amount of optimization can make this approach feasible. Literally, you would need to store around $2^{750}$ primes into a single atom, which is an unimaginably large number, and for all intents and purposes infinite. Tylo, your calculation is wrong, by the way, that should be $2^{1013.5 - 265.75}$ (just about 744 orders of magnitude off :p)
Jun
24
comment If we can find prime numbers larger than 17 milion digits, why can't we find all 1024bit primes?
@user129789 Even if we assumed that you could calculate all those $2^{1024}$ primes - never mind all their products pairwise, to make a huge lookup table - instantly (that is ludicrous but let us imagine). How much space would you need to store them all (1024 bits per prime)?
Jun
19
comment What is U2FsdGVkX1?
And just for completeness (since the quote only answers half of the question) starting the files with "Salted__" does not give away information beyond the fact that the file was encrypted with (or at least for) OpenSSL, which is assumed to not be secret. So it isn't insecure.
Jun
19
comment Is a small size block cipher usable?
For 32-bit block sizes I think a few hundred megabytes of output should be sufficient to distinguish between a CTR keystream and a random function, actually, assuming the plaintext has sufficient structure.