10,594 reputation
11044
bio website vyznev.net
location Helsinki, Finland
age
visits member for 2 years, 8 months
seen yesterday

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.


Feb
8
reviewed Satisfactory Deriving Keys for Symmetric Encryption and Authentication
Feb
8
reviewed Excellent Blind quantum computing and fully homomorphic encryption
Feb
8
reviewed Satisfactory On-the-fly computation of AES Round Keys for decryption?
Feb
8
awarded  Custodian
Feb
8
reviewed Satisfactory A situation where security by obscurity might be the best solution - or am I wrong?
Feb
8
revised What are rounds in the context of ciphers?
edited tags
Feb
7
revised AES-CTR vulnerability to cryptographic oracle
edited tags
Feb
7
answered AES-CTR vulnerability to cryptographic oracle
Feb
6
comment Is such a crypto-system available?
This earlier question looks remarkably similar. Is that just a coincidence, or is there some connection I'm missing?
Feb
4
reviewed Approve suggested edit on Random oracle model proofs and programmability
Feb
1
comment Is there any known malleability of scrypt outputs?
@fgrieu: Would you mind posting something like your comment above as an answer?
Feb
1
comment Why would this method of discrete logarithm finding not work?
I tried to LaTeXify your question, but I'm not sure I interpreted all the notation right. (In particular, what's (b^i).F supposed to mean?) Please check it and fix any mistakes I may have introduced.
Feb
1
revised Why would this method of discrete logarithm finding not work?
needs more dollar signs
Jan
31
revised Cryptographic Symmetric Stream Cipher
added 1647 characters in body
Jan
31
comment Cryptographic Symmetric Stream Cipher
@Auth: Yes, as long as no-one else knows the key. AES is a symmetric block cipher, i.e. a pair of pseudorandom permutations, chosen by a key, that are inverses of each other. The designation of one permutation in the pair as the "encryption function" and the other as the "decryption function" is completely arbitrary. (However, note that such reuse makes the analysis of chosen plaintext/ciphertext attacks more complicated. Still, if all ciphertexts are authenticated and there's no way for an attacker to inject chosen plaintext, this may not matter.)
Jan
30
comment Cryptographic Symmetric Stream Cipher
@Auth: Technically, yes. However, note that, with symmetric crypto, anyone who can compute $P$ can also compute $S$, and vice versa. If this is not desirable, you'd need to use some kind of asymmetric encryption scheme. Your question, however, did not mention anything about that.
Jan
29
answered Cryptographic Symmetric Stream Cipher
Jan
29
revised What is a smart card?
retag, copyedit
Jan
29
revised Using Chi-Square for Vigenère Cipher
edited tags
Jan
29
comment RSA and One Time Password (OTP) service
And why should the server trust the results of whatever verification the client does (or claims to have done)?