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Jan
27
answered Cryptanalysis of an certain algorithm
Jan
27
comment How can I encrypt more than 64 bit with the Data Encryption Standard?
@Goot: yes, in CBC mode, you use the same key for each block.
Jan
26
answered Random numbers for Rabin-Miller primality tests
Jan
26
reviewed Approve suggested edit on ElGamal in private set intersection: how to handle negative numbers?
Jan
25
awarded  Nice Answer
Jan
25
comment Cryptography: Oblivious Transfer with at most one transfer?
Nope; the solution listed as a duplicate doesn't meet the criteria; Alice sends back two bits, not just one...
Jan
25
comment Cryptography: Oblivious Transfer with at most one transfer?
possible duplicate of Protocol for Randomized Oblivious Transfer?
Jan
24
answered Symmetric encryption is no longer necessary?
Jan
24
answered Are any of the major asymmetric ciphers distinguishable (EG, RSA, ECC)?
Jan
24
reviewed Approve suggested edit on distinguishing-attack tag wiki
Jan
24
reviewed Approve suggested edit on distinguishing-attack tag wiki excerpt
Jan
24
comment What is the relation between Discrete Log, Computational Diffie-Hellman and Decisional Diffie-Hellman?
@Jalaj: if you go through the summary, it applies only to groups "where all the multiple prime factors of |G| are polynomial in log|G|"; this is not true in general for well-chosen $p$ values.
Jan
24
comment Shamir Secret Sharing Modular Reduction
I believe the idea is that recover $k \bmod m$ without anyone being able to learn more about $k$. If so, it doesn't quite work; someone learning $k \bmod m$ and the number of iterations we went through the above procedure can easily rederive the original $k$ value.
Jan
23
comment Recovery of RC4 key when S-box 0 stage or 1st stage known
@Hedgie: "I can XOR plaintext and cipher and actually get S"; errr, no, you cannot recover the state of S by exclusive or'ing the plaintext and the ciphertext. Xor'ing the plaintext and the ciphertext gives you the keystream; there is no known practical way to recover the state S of the permutation from the keystream.
Jan
23
comment Question about SHA-2 (and potentially similar hashing algorithms)
So, you're suggesting that the attacker be allowed to select those constants? After all, during an attack, the attacker is submitting values to hash; if those 'constants' depend on the values, the attacker can, by selecting the appropriate initial string, he gets to pick the 'constants' that the hash function will use.
Jan
23
revised Keeping IV secret for AES CFB mode
edited tags
Jan
23
answered Question about SHA-2 (and potentially similar hashing algorithms)
Jan
20
comment Rabin code same message sent with different $N$
@Alexander: does Rabin really avoid public exponents, or does it just use a fixed value?
Jan
20
comment Rabin code same message sent with different $N$
You might consider reviewing the related question crypto.stackexchange.com/questions/6713/…
Jan
20
revised How can I break this encryption scheme?
added 95 characters in body