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6h
comment Evidence of practical differential cryptanalysis attacks
Not a cipher, but the MD5 collisions were due to differential cryptoanalysis.
10h
comment Can cycle finding techniques reduce the memory usage of the MitM attack against 2DES and 3DES?
You can't just equate the number of operations with time, you also need to take parallelism into account. (And DJB argues that you can't neglect the cost of memory access circuitry for many attacks either.) With cycle-finding I'd expect the cost of memory to be cheap compared to the cost of all those parallel DES computation circuits. For example such a computer might have ~4 GB of memory and $2^{20}$+ DES circuits, running for ~$2^{36}$ timesteps (where each timestep is one DES invocation).
12h
reviewed Approve Can cycle finding techniques reduce the memory usage of the MitM attack against 2DES and 3DES?
13h
reviewed Close Creating of finite field over small prime number for Elliptic Curve
13h
reviewed No Action Needed If you hashed a hash an infinite number of times would you end up with a unique hash?
13h
reviewed No Action Needed Password length versus hash length?
13h
reviewed No Action Needed Key iteration count while using random keyfile larger than master key
15h
comment Can cycle finding techniques reduce the memory usage of the MitM attack against 2DES and 3DES?
1) In the simplest case we could truncate. If we need a tweak to repeat the whole experiment with a different hash function (not sure if that's required) we can use any kind of tweakable hash (preferably a cheap one) 2) I don't think the block-size matters at all with most modes of operation (including ECB, CBC and CTR). We simply need a long enough known plaintext/ciphertext pair.
15h
comment Why does applying 56-bit DES twice only give 57 bits of security?
@fgrieu I originally planned to verify the technique experimentally with small keys before posting about it, but since I don't have the time for that at the moment, I've asked it as a question: Can cycle findinding techniques reduce the memory usage of the MitM attack against 2DES and 3DES?
15h
asked Can cycle finding techniques reduce the memory usage of the MitM attack against 2DES and 3DES?
1d
revised SHACAL-2 vs. AES as underlying block cipher for Secure Hash (aka SHA-256)
added 185 characters in body
1d
comment SHACAL-2 vs. AES as underlying block cipher for Secure Hash (aka SHA-256)
@EvgeniVaknin Depends on the hardware. AES will probably be faster than SHACAL-2 on most processors. But on processors without AES-NI the difference will be smaller than the ratio of the number of rounds. You also need to keep in mind that a hash gives an attacker much more control over the inputs, so the same block cipher might need more rounds when used as hash compared to being used as encryption.
1d
revised SHACAL-2 vs. AES as underlying block cipher for Secure Hash (aka SHA-256)
added 121 characters in body
1d
comment SHACAL-2 vs. AES as underlying block cipher for Secure Hash (aka SHA-256)
You can use AES to build a secure MAC (CBC MAC and its derivatives). Unlike your suggestion, these constructions use AES with a random key, which the attacker doesn't know.
1d
answered SHACAL-2 vs. AES as underlying block cipher for Secure Hash (aka SHA-256)
1d
comment Why cant I use ECB with some obfuscation for random access data stored in say a DDR
Why not do it properly? XTS mode is similar to your idea (it combines the address with the data), but actually secure.
1d
reviewed Close Can anyone provide a simple java code for bilinear pairing?
1d
reviewed Reviewed Encryption of plain text using stream cipher algorithm
1d
reviewed Reviewed Decoding Base64 encoded password with internal hashing
1d
reviewed No Action Needed Does SRP reduce to DH key exchange when shared password is not secret?