328 reputation
19
bio website
location
age
visits member for 1 year, 4 months
seen yesterday

Dec
17
comment Dancing confusion with Daniel J. Bernstein's stream ciphers
XChaCha implementation (XSalsa20's nonce and ChaCha's diffusion): github.com/lightbit/kripto/blob/master/lib/stream/chacha.c
Nov
29
revised block cipher algorithms with variable block lengths
added 1 character in body
Nov
29
answered block cipher algorithms with variable block lengths
Nov
19
comment Do data-dependent rotations have any advantage over fixed rotations?
Ignoring patents, implementation problems, hardware do disadvantages still outweigh advantages?
Nov
19
accepted Do data-dependent rotations have any advantage over fixed rotations?
Nov
18
asked Do data-dependent rotations have any advantage over fixed rotations?
Nov
16
comment Block cipher to encrypt 8 bytes/64 bits - Use 64 or 128 bit cipher?
If you want compact 64-bit block cipher, I would suggest Speck or RC5. XTEA should also be fine, but you have to be careful with key management (as always).
Nov
14
comment Why we can't implement AES 512 key size?
AES-like block cipher used in Whirlpool hash has 512-bit block size and key size.
Nov
11
awarded  Yearling
Nov
11
comment Extending key sizes in Salsa20 and ChaCha?
@John It depends how long stream would be. If key1 = 12 and key2 = 19, you will get same blocks, but with different offset. Result is similar to nonce reuse, which is serious defect. Counter must always be initialized to the same fixed value.
Nov
11
comment Extending key sizes in Salsa20 and ChaCha?
@John Lets say you have key1 = 12 and key2 = 11. Then first block of key1 will be the same as second block of key2. Because counter will increase key.
Nov
11
comment Extending key sizes in Salsa20 and ChaCha?
@John Adding rounds will of course affect performance. Why do you think 24 is enough/needed for 384-bit key and 28 for 448-bit key? You would have to analyse Salsa20 like Mouha and Preneel did to know how many rounds you need.
Nov
11
revised Extending key sizes in Salsa20 and ChaCha?
XSalsa20 added, counter comment
Nov
11
revised Extending key sizes in Salsa20 and ChaCha?
added keccak
Nov
11
revised Extending key sizes in Salsa20 and ChaCha?
added 6 characters in body
Nov
11
answered Extending key sizes in Salsa20 and ChaCha?
Nov
9
comment Extending key sizes in Salsa20 and ChaCha?
@John I think storing keys safely is bigger issue than "short" keys. Why not store plain-text than? Or use one-time pad? And if the key is generated using PRNG you have to have 448-bit of entropy.
Nov
9
comment Extending key sizes in Salsa20 and ChaCha?
@John Will you memorize 448-bit random key?
Nov
3
accepted Is XCBC where k2 and k3 might be the identical, secure?
Nov
3
revised Is XCBC where k2 and k3 might be the identical, secure?
edited title