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seen Jul 27 at 13:09

Oct
24
suggested suggested edit on A discrete-log-like problem, with matrices: given $A^k x$, find $k$
Oct
23
revised Because the algorithm is known, it is no longer a trade secret
fixed typos
Oct
23
awarded  Custodian
Oct
23
reviewed Reviewed Finding the LFSR and connection polynomial for binary sequence.
Oct
23
reviewed Reviewed Because the algorithm is known, it is no longer a trade secret
Oct
23
suggested suggested edit on Because the algorithm is known, it is no longer a trade secret
Oct
23
comment One time pad key exchange
Well, I construe one time pad as a pad that you use one time. Please also note that the distinction you're trying to make is already part of the answer: sequences thus genereated are "only" pseudo-random. Also, you'll have a hard time defining what a perfectly random string is in practice: anything that you'll use to generate it has some bias...
Oct
22
revised Traditional DES scheme in Unix crypt function
E does not expand the key, but rather the half state
Oct
22
comment Could the Enigma algorithm be classified as a Feistel network?
@JohnDeters: I'd be interested in your definition of a stream cipher and a block cipher then. (You might have noted the caveat in my previous comment that the view I have of a stream cipher might not be universally recognized; but at least I gave one.)
Oct
22
revised Hash function from narrower block cipher operated in CBC-encryption mode?
added 43 characters in body
Oct
22
revised Hash function from narrower block cipher operated in CBC-encryption mode?
added 4 characters in body
Oct
22
comment Hash function from narrower block cipher operated in CBC-encryption mode?
@fgrieu: you are correct that the case $n>1$ cannot be attacked since the key after first round was the same for both messages and due to the bijectivity of the block cipher, a collision could not occur. I updated the last paragraph accordingly. As I write, I'm concerned about the small "bandwidth", and there is probably a lot to do, but would require some more time.
Oct
22
revised Hash function from narrower block cipher operated in CBC-encryption mode?
update for the case $n>1$
Oct
21
awarded  Revival
Oct
21
revised Hash function from narrower block cipher operated in CBC-encryption mode?
added 66 characters in body
Oct
20
comment Shamir Secret Sharing - Threshold decryption implementation
The polynomial $f$ underlying Shamir's $(t,n)$ secret scheme is such that it has degree $t-1$ and $f(0)$ is the key (or secret) to be shared. The share given to participant $i$ is $f(i)$. You can compute $f$ using Lagrange interpolation from $f(j)$, $j=0,...,t$. See also section 2.1 of the paper linked in the answer above.
Oct
19
awarded  Analytical
Oct
19
revised Using pairings to verify an extended euclidean relation without leaking the values?
improved the description of the problem
Oct
19
comment Using pairings to verify an extended euclidean relation without leaking the values?
The exact definition of the $P_i$, $q_i$, and $s$ are not really relevant to the question. But in case you really want to know the dirty details, look at the dirty details of set intersection queries...
Oct
19
suggested suggested edit on Using pairings to verify an extended euclidean relation without leaking the values?