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Oct
10
answered NP complete problems related to permutations of binary vectors or block ciphers
Oct
10
comment The Goldreich-Goldwasser-Micali Construction with bad PRGS
I very much doubt that GGM will offer useful security if the underlying PRG has a significant bias. I think your argument is unconvincing and your hypothesis is unlikely to hold.
Oct
8
reviewed Reject timestamping tag wiki excerpt
Oct
8
reviewed Reject timestamping tag wiki
Oct
8
comment Predicting values from a Linear Congruential Generator
See also security.stackexchange.com/q/4268/971 for more on cracking LCGs (though with a different set of assumptions).
Oct
8
answered WIN LM Password Hashes (using John the ripper)
Oct
7
comment Openssl & RSA : how many public exponents are possible?
There are no security benefits to large exponents (assuming you use RSA properly, including proper padding and so forth; and if you don't use RSA properly, then you've got bigger problems and might be in trouble no matter what exponent you use).
Oct
7
answered Self authenticating tamper resistant first meetings
Oct
7
revised Relationship between Elliptic Curve Discrete Log, Integer Discrete Log, and Integer Factorization
Fix formatting. Make the question much more concise.
Oct
7
awarded  Revival
Oct
7
awarded  Nice Question
Oct
4
answered Elliptic curve cryptography attack vector
Oct
3
comment Calculating ciphersize of Paillier, SSE and OPE
Similar comments apply to SSE and OPE. It is extremely unlikely that 64 bits will be sufficient for the ciphertexts of SSE and OPE. And, as explained in my answer, the length of the ciphertexts for OPE and SSE depends upon which scheme you use, so there is not one answer to the question (your answer seems to be based upon the erroneous premise that there is only a single algorithm for SSE/OPE).
Oct
3
answered Calculating ciphersize of Paillier, SSE and OPE
Oct
3
comment Calculating ciphersize of Paillier, SSE and OPE
A Paillier ciphertext will be a lot longer than 64 bits. Probably more like 4096 bits (assuming a 2048-bit key, which is about the level needed to provide good security today, given the state of modern factoring algorithms).
Oct
3
comment Reordering non-block-aligned parts with DES in ECB mode
Can you tell me the context where you ran into this? What makes you think it is possible to exchange the first line with the last? Why are you so set on that specific goal? That seems awfully specific (as opposed to, say, swapping some pair of entries of the attacker's choice). I assume you know that you can swap any pair of ciphertext blocks, and the corresponding plaintext blocks will be swapped? So if you can find a pair of blocks that, when swapped, leaves the format of the plaintext undisturbed (and such that the exchange is favorable to the attacker), that's a valid attack.
Oct
3
revised Generate key pair deterministically from a particular seed
Clean up teh question and title.
Oct
3
revised Using multiple secret keys
added 168 characters in body; added 40 characters in body
Oct
3
answered Using multiple secret keys
Oct
3
comment Using multiple secret keys
Yeah, that's not gonna work. Someone who is not physically at the specific location, but who knows where the specific location is, can still infer the key and decrypt the ciphertext. There's been academic work on this sort of problem (e.g., by Dorothy Denning), but it's a much harder problem than you seem to realize.