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Aug
25
reviewed No Action Needed Found a way to crack AES-128, what now?
Aug
25
reviewed Close Seemingly simple decryption question
Aug
25
reviewed Leave Open Solution with high decryption cost and low encryption cost
Aug
25
reviewed Close Variants of AES?
Aug
25
reviewed Close Efficiently map $2^n$ unique 64-bit vectors to $2^n$ $n$-bit vectors where $n < 64$?
Aug
25
comment Efficiently map $2^n$ unique 64-bit vectors to $2^n$ $n$-bit vectors where $n < 64$?
I'll vote to close as well; but you might want to consider: "what properties do you want from your mapping?" If you want just any mapping, just chopping off $64-n$ bits off the vectors works fine -- is there a reason why that isn't sufficient?
Aug
24
comment Simple proof that shows AES is not a uniform permutation on any n-bit string?
@ddddavidee: actually, there are block ciphers that can implement an odd permutation; they're not common, but they most certainly do exist. AES (as well as the vast majority of block ciphers) will always do an even permutation.
Aug
23
awarded  modes-of-operation
Aug
21
comment CBC-MAC key can be added to ciphertext?
@Kingland: yes (or somehow otherwise have both sides arrive at the same secret keys)
Aug
21
revised CBC-MAC key can be added to ciphertext?
added 334 characters in body
Aug
21
answered CBC-MAC key can be added to ciphertext?
Aug
20
comment Regular MACs vs Carter-Wegman MAC
@CodesInChaos: some CW MACs are more tolerant about nonce reuse. It all depends on the crypto part that takes the output of the universal hash, and disguises it. Earlier CW MACs did a hash over the universal hash and the nonce; nonce reuse would tell the attacker little (unless the universal hash output was also the same -- a low probability event by the definition of universal hash). Modern CW MACs tend to use the universal hash output xor'ed with an encrypted form of the nonce -- that's a lot dicier with nonce reuse.
Aug
20
comment Recover plaintext from truncated ciphertext using AES for FPE
Yes, changing the AES key round would suffice, but (IMHO) is more heavy weight than you need. Instead, I would suggest you put the round index into the (currently zero) padding you use to pad out the 32-bit into a full 128 bits.
Aug
20
reviewed Leave Open Cryptography vs Security
Aug
20
reviewed Close How to generate ECC (160 bits) Keys with OpenSSL?
Aug
20
comment Recover plaintext from truncated ciphertext using AES for FPE
Two comments: for a Feistel cipher, you need to make each round function different (say, stir in the round index as an input to AES); otherwise, you open yourself up to slide attacks. Also, step 5 says "if the ciphertext is not in range, keep on doing Feistel until it is". Actually, to be able to decrypt unambiguously, you need to rerun the entire encryption procedure (including all 7 rounds).
Aug
19
reviewed Close Why can't you decrypt an encrypted message with just the public key?
Aug
19
reviewed Close Security implication of exporting private key
Aug
19
reviewed Close GPG vs PGP vs OpenSSH and management of them
Aug
19
reviewed Close Rely on NSA Suite B Cryptography?