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Jun
24
answered What prime lengths are used for RSA?
Jun
23
reviewed Approve How are timestamps verified?
Jun
20
awarded  Revival
Jun
20
answered Double-and-add/Montgomery VS blinding
Jun
14
awarded  Revival
Jun
14
comment Meaning of entropy of a bitstring in NIST SP 800 - 90A
If passing tests was enough, competitions like eSTREAM would be meaningless. Anyone can run some statistical tests on a PRNG; but it takes years and many cryptographers to assess the actual security.
Jun
14
comment Meaning of entropy of a bitstring in NIST SP 800 - 90A
What I mean is that while statistics can detect things that attackers also know, attackers may know things that statistics do not detect. E.g. for a purportedly "strong" PRNG, if a statistical test detects a bias, then the PRNG is weak; but if the test detects nothing, then one must not conclude that the PRNG is strong. In practice, even bad PRNG are "perfect" from a statistical point of view.
Jun
14
answered Meaning of entropy of a bitstring in NIST SP 800 - 90A
Jun
14
answered Inserting a backdoor into a cryptographic hash function
May
12
awarded  Enlightened
May
12
comment How can I convert a DER ECDSA signature to ASN.1?
It is specified in the standard for DHE parameters, and in the other standard for ECDHE parameters. In the former case (DHE), it is the concatenation of the client random, the server random, and the encoded DH values (TLS encoding, not ASN.1/DER). With ECDHE, this is an encoding of the curve description and the server ECDH public value, this time without the client and server randoms.
May
12
awarded  Nice Answer
May
9
answered At what point can you you implement crypto algorithms?
Apr
27
awarded  Good Answer
Apr
26
awarded  Enlightened
Apr
26
awarded  Nice Answer
Apr
25
answered If you hashed a hash an infinite number of times would you end up with a unique hash?
Apr
15
awarded  Nice Answer
Apr
13
awarded  Nice Answer
Apr
7
comment How can rainbow tables be used for a dictionary attack?
@FredericoSchardong: see this article for some thorough analysis. It is not an easy read. Informally, when you build rainbow/Hellman tables, you accumulate chains with distinct end points; the more chains you insert, the higher the probability that the next chain merges with one already in the table, and thus was lost CPU. At some point it no longer is worth it; you'd better start a new table. The "1.7" factor comes from that effect.