10,659 reputation
11045
bio website vyznev.net
location Helsinki, Finland
age
visits member for 2 years, 8 months
seen 3 hours ago

I'm not really a cryptographer, I just play one on the internet.

Seriously, I'm just a programmer and mathematician interested in puzzles and information security. I don't have any kind of formal crypto training, but I've picked up a few things here and there over the years. Topics I'm particularly interested in include protocol design and analysis, classical ciphers and information-theoretically secure crypto techniques such as one time pads and secret sharing schemes.

Please consider any (original) code I post to Stack Overflow (and other Stack Exchange sites) to be released under CC-Zero unless stated otherwise. You may do whatever you want with it and don't have to credit me in any way, although of course that would be nice.


Jan
12
comment Difference between CBC-MAC and CMAC
@figlesquidge: While the information requested probably is obtainable from Wikipedia, it's not very clearly presented there. IMO, this is a perfectly good reference question, and I'm hoping to see a concise and comprehensive answer summarizing the main differences.
Jan
11
reviewed Approve suggested edit on private-set-intersection tag wiki excerpt
Jan
11
answered If G is a secure PRG and G' is a function of G, is G' secure?
Jan
9
awarded  Nice Answer
Jan
3
comment Replay attack in ECB mode
@figlesquidge: Indeed. (Just to be clear, the fact that the link works is not a bug; I've reported the actual bug to SE privately, since it has (minor) security implications.)
Jan
3
revised Replay attack in ECB mode
testing...
Jan
2
wiki created transposition-cipher description
Jan
2
wiki created transposition-cipher excerpt
Jan
2
revised About Cryptography in a Character Language
edited tags
Jan
2
revised What are requirements for this grille?
edited tags
Jan
2
revised What is total key space in transposition algorithms
create new transposition-cipher tag
Dec
28
comment Why xor is a linear operation but ordinary adding is not
Nitpick: the integers with ordinary addition modulo 256 are not a vector space over any finite field. In fact, they're not a vector space at all, although they are an abelian group, and therefore a module over the ring of integers.
Dec
27
revised How to attack this authentication protocol from “Cryptography: An introduction”
edited tags; edited title
Dec
27
answered How to attack this authentication protocol from “Cryptography: An introduction”
Dec
27
revised What does this Authentication protocol achieve and what information is shared?
more $$$$ (and a few {{}})
Dec
27
comment How to attack this authentication protocol from “Cryptography: An introduction”
Ps. Where is this exercise from, anyway?
Dec
27
comment How to attack this authentication protocol from “Cryptography: An introduction”
possible duplicate of What does this Authentication protocol achieve and what information is shared?
Dec
27
revised Two-dimensional S-Box
edited tags
Dec
27
answered Using HMAC to secure a “widget”
Dec
27
comment Off-the-record communication
@RamRachum: No, because that would lose the deniability property we wanted in the first place: for a given $W' = W \oplus SHA(m) \oplus SHA(m')$, finding $Y'$ and $Z'$ such that $W' = H(Y' + Z')$ (for any meaning of $+$) would require breaking the preimage resistance of $H$.