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visits member for 2 years, 8 months
seen Apr 17 at 19:38

Mar
26
comment Solving hard problems in $\mathbb Z_{p}^{*}$ when $\mathbb p$ is close to $\mathbb 2^{n}$
Thanks, the notation was indeed suboptimal.
Mar
26
answered Solving hard problems in $\mathbb Z_{p}^{*}$ when $\mathbb p$ is close to $\mathbb 2^{n}$
Mar
25
comment Are safe primes $p=2^k \pm s$ with $s$ small less recommandable than others as a discrete log modulus?
You're right, fixed.
Mar
25
revised Are safe primes $p=2^k \pm s$ with $s$ small less recommandable than others as a discrete log modulus?
added 7 characters in body
Mar
14
answered How to perform Multiplicative Inverse Modulo in IDEA
Jan
31
answered Is (2^333)-1 a prime number?
Jan
24
comment Discrete logs on elliptic curve with embedding degree 3 with the 'MOV' attack
I used SAGE, it has all kids of useful things. I've posted the code to do the above here.
Jan
22
answered Discrete logs on elliptic curve with embedding degree 3 with the 'MOV' attack
Jan
10
comment Is it possible to break a hash-based block cipher?
CBC doesn't help you; what you get is something like Block 0: IV Block 1: IV ^ M[0] ^ H(K, 0) Block 2: (IV ^ M[0] ^ H(K, 0)) ^ M[1] ^ H(K, 1) ... By XORing IV with the first block, the first with the second, etc, you are able to recover M[i] ^ H(K, i)
Jan
10
comment Is it possible to break a hash-based block cipher?
What you describe is not a block cipher, as a block cipher by definition has no notion of position (i.e. $n$). What you're describing is a stream cipher made out of a hash in counter mode (see Salsa20 for a similar construction).
Jan
9
comment Choosing good parameter for Lenstra's elliptic curve factorization
I am unsure what you mean by "factor" in the ECM case; if you mean the integer multiplied by P, then yes, that's it.
Dec
29
answered Choosing good parameter for Lenstra's elliptic curve factorization
Nov
5
answered Why doesn't CTR mode require blocking?
Sep
27
awarded  Booster
Sep
27
awarded  Announcer
Aug
22
awarded  Yearling
Jun
26
comment How does the cyclic attack on RSA work?
Right, just changed the answer to make the modulo explicit.
Jun
26
revised How does the cyclic attack on RSA work?
added 9 characters in body
Jun
26
answered How does the cyclic attack on RSA work?
Jun
13
comment Why would anyone use an elliptic curve with a cofactor > 1?
Yeah, you're right. Whenever the $xy$ coefficient is nonzero, there's a trivial order 2 point. When it's not, you get either singular (unusable) or supersingular (weaker) curves.