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Dec
3
reviewed Approve IV's from Crypto++ AutoSeededRNG always ends the same: Problem with the PRNG?
Dec
3
reviewed Approve Graphically representing points on Elliptic Curve over finite field
Dec
2
revised function-evaluation wiki description
oh dear... that's really not what it means at all
Dec
2
revised function-evaluation wiki excerpt
oh dear... that's really not what it means at all
Dec
2
reviewed Approve Why use two affine transformations in Multivariate Cryptography?
Dec
2
reviewed Close Why is appending the key to a mesage and then hashing that insecure if the hash isn't weakly collision resistant?
Dec
2
answered Splitting a password for dual roles
Dec
2
reviewed Leave Open Splitting a password for dual roles
Dec
2
revised Splitting a password for dual roles
copyedit
Dec
2
reviewed Leave Open Who uses the RSA BSAFE library?
Dec
2
reviewed Close becoming a cryptographer after math studies
Dec
2
reviewed Close Hash function with values in a multiplicative group of prime order
Dec
2
reviewed Close How does identification currently work with the German identity card?
Nov
30
comment Is it theoretically possible to construct a string that contain its own hash value?
@Alex: With respect to what parameter? With respect to the hash output length $k$, it's clearly in NP($k$), assuming that computing the hash of a given string is in P($k$). By the argument given above, if the hash is secure in the sense described, finding such a string cannot be in P($k$). (Yes, the existence of secure hash functions implies that P ≠ NP.) With respect to the input string length, finding such a string (if there is one to be found) takes on average a constant number of hash evaluations, and is thus in ZPP.
Nov
30
reviewed Approve cmac tag wiki excerpt
Nov
30
reviewed Approve cmac tag wiki
Nov
28
comment Can homomorphic encryption filter?
However, using methods similar to those in your answer, it would be possible to query e.g. for "the first 50 students with scores higher than 90%" (with null values returned if there weren't that many matching records).
Nov
28
revised Can the XOR of two non-collision-resistant hashes be collision resistant?
added 778 characters in body
Nov
28
revised Can the XOR of two non-collision-resistant hashes be collision resistant?
copyedit
Nov
28
answered Can the XOR of two non-collision-resistant hashes be collision resistant?