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Mar
19
reviewed Leave Open Deciphering text encrypted with a changing cipher
Mar
19
reviewed Leave Closed Is there any task better and less complex than oblivious transfer?
Mar
18
comment Concatenation of two strong hashes may have striking weakness
If $H_0$ and $H_1$ are independent hashes, the intuitive result holds in ROM, I guess.
Mar
18
comment Concatenation of two strong hashes may have striking weakness
Preimage resistance is indeed much more difficult to define than most basic texts pretend. Many natural definitions are defective in that obviously insecure constructions are secure according to the definition (e.g. choose an element at random from the co-domain: the preimage-finder must find a preimage of that element). I think a plausible definition is: the adversary chooses a suitable plaintext distribution, you sample from the distribution and compute the hash value, finally the adversary recovers any preimage. Under this definition, concatenation is not preimage-resistance-preserving.
Mar
16
reviewed Leave Closed Block size of 128 bit in (quantum) future
Mar
16
reviewed Close Implementing modular reductions (n*n)
Mar
16
reviewed Close How to check if a sequence is generated by a linear congruential generator?
Mar
13
reviewed Leave Open Of what use is my code for finding prime numbers of a certain size?
Mar
11
reviewed Approve How to compute accumulated values in bilinear map accumulators
Mar
11
reviewed No Action Needed Workaround to implementing Forward Secrecy
Mar
11
reviewed Leave Open Known plaintext, unknown 128 bit block cipher
Mar
11
reviewed Close What is the probability of finding 4 equal bytes?
Mar
11
reviewed Close Fault encryption attack on RSA
Mar
4
reviewed No Action Needed How difficult is it to get a key using simple XOR
Mar
4
reviewed No Action Needed AES key from encrypted text and VI
Mar
4
reviewed No Action Needed AES different modulo operations
Mar
4
reviewed Close AES mode scheme feedback
Mar
4
reviewed Leave Open Predicting Google Authenticator OTP Codes
Mar
4
reviewed Close Difference between Kerberos and GDOI?
Mar
4
reviewed Leave Closed How to compare between two cryptographic algorithms in terms of security?