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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
5
comment Does Grover's algorithm effect block size or only key size?
I believe 3DES (or any cipher with a 64-bit block size) in CTR, CFB or OFB mode can be distinguished from a random stream after a few dozen gigabytes of output. Not a problem for most applications, though.
Jan
4
comment How will Cryptography be changed by Quantum Computing?
@mary They are hardly a practical reality, we don't know if it's physically possible to build a sufficiently large quantum computer. But in any case, a small block size allows you to distinguish the output of a block cipher from a random stream, which is a weakness - I suspect Grover's algorithm would also speed up this type of attack, requiring you to increase the block size accordingly as well.
Jan
4
reviewed Reviewed Example Rainbow Table Generation
Jan
4
reviewed Reviewed Do known-plaintext attacks exist for public key encryption?
Jan
4
reviewed Reviewed How will Cryptography be changed by Quantum Computing?
Jan
4
comment How will Cryptography be changed by Quantum Computing?
Actually, I'm not sure 128 bit blocks would be sufficient if QC's became a reality, I'm not sure if generic distinguishers are affected by Grover's algorithm but it could be something to keep in mind. That said, increasing block and key size is an easy process, coming up with a secure asymmetric algorithm is not.
Jan
4
reviewed Approve Does the elliptic curve (EC) cryptosystem outperform RSA and DL cryptosystems?
Jan
4
revised Calculating RSA private exponent when given public exponent and the modulus factors using extended euclid
added 3 characters in body
Jan
3
comment A proof-of-work random number generation system for Pokémon
@JoeZeng You require a trusted server to accomplish this, which'll check the result and broadcast to other players (or certify on request) that such and such user did successfully complete the work. Or you could use a p2p network, Bitcoin style, but this gets rather unreasonable for a Pokemon game at this point, no?
Jan
3
comment Do known-plaintext attacks exist for public key encryption?
Some improper terminology here, padding is not blinding. Blinding is used to prevent a third party gaining information about some data, optionally allowing him to blindly operate on it, which has little to do with semantic security. Great answer otherwise.
Jan
3
revised Calculating RSA private exponent when given public exponent and the modulus factors using extended euclid
added 1 characters in body
Jan
3
answered Calculating RSA private exponent when given public exponent and the modulus factors using extended euclid
Jan
3
comment Needing to encrypt plain sight information
@Andrew Also, dchest didn't say "encrypt the data", he said "encrypt the key" - there is a big difference, the data is still only encrypted once ;)
Jan
3
comment Needing to encrypt plain sight information
But the problem doesn't make sense if the resulting decrypted page is the same for all users, just give them all the same key. Unless the keys are used somewhere else, it does not make any difference.
Jan
2
reviewed Reviewed Hill cipher, unknown letter value
Dec
31
comment Time Capsule cryptography?
Point 2 is not a very convincing argument, to be honest. Just because the probability is not zero doesn't mean it's going to happen. Also, speed limit is more like 9GHz, at least to public knowledge.
Dec
27
comment Future-Proof Versioning and Validation
@andrewcooke For that part, you can use a HMAC akin to what I described in my answer to be able to detect when the version number is changed by anyone other than the legimitate owner of the file.
Dec
27
comment Future-Proof Versioning and Validation
@andrewcooke Well, if the old algorithms are broken beyond repair, not much you can do about it, beyond asking your users to migrate their files to newer versions. Algorithms don't live forever. What attacks are you thinking about?
Dec
27
answered Future-Proof Versioning and Validation
Dec
27
comment Time Capsule cryptography?
@IanBoyd The puzzle can be efficiently created. It's solving it that's difficult.