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4,027
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76/100 score
30/20 answers
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~54k people reached

17h
comment Fast PKI for embedded device
if you have 64-bit integer operations, ed25519 should take less than 2 million cycles to verify a signature, which means a tenth of a second
19h
comment Fast PKI for embedded device
Is it a 32-bit CPU?
19h
comment VKO GOST R 34.10-2001 (described in RFC4357), Key Agreement Algorithm. Looking for its implementation/detailed description/examples
It should also be noted that GOST R 34.10-2001 was deprecated, and will no longer be in service as of 2018
19h
comment VKO GOST R 34.10-2001 (described in RFC4357), Key Agreement Algorithm. Looking for its implementation/detailed description/examples
tools.ietf.org/html/rfc5832
1d
comment One-time-pad with multiplication
@mikeazo multiplication in a finite field, say $GF(2^8)$
1d
comment IV/Nonce in CTR&GCM mode of operation
@Paya that note was in regards to the full 128-bit internal IV; the GCM specification prevents using an all 0 IV by starting the block counter at 1 when using a 96-bit all 0 input IV, and running GHASH on an input IV of more than 96-bits, thus turning it into a nonce with regards to H.
2d
comment Does the encryption algorithm DES perform random permutations? If so how is information not lost?
crypto.stackexchange.com/questions/3/…
May
23
comment Huffman encoding of hashes
@RickyDemer I have a Base128 encoder I wrote years ago that can get it down to 19!
May
23
answered Huffman encoding of hashes
May
21
comment Do hand-based hash functions / MACs exist?
as long as the "block size" (domain*char count) is large enough. 4 character Base64 gives you 16 million different outputs. Using table lookups can make it human calculable within a reasonable timeframe
May
20
comment Do hand-based hash functions / MACs exist?
You can use a simple 4-letter format preserving block cipher (base 64?) in CBC-MAC mode, if the output domain needs to be all caps/numbers, you can reformat the 24-bit output to 6 4-bit values or 5 5-bit values.
May
15
comment AES process candidates implementations and usages
Twofish, Serpent
May
14
comment Reciprocal block ciphers
@Melab if the previous did not answer the question I don't know what will. matrix multiplication in AES is NOT done mod 256, it is done in a finite field.
May
13
comment Reciprocal block ciphers
@Melab the same way they do in AES, they are not involutions. The key schedule is what makes the Feistel structure an involution, regardless of the F-function used. I used AES because it was convenient and fast. I suppose it could be applied to a Lai Massey cipher, I have none in my code library to modify and test
May
13
comment SHA3 Keccak, absorbing data to the state
crypto.stackexchange.com/questions/12720/…
May
11
comment Reciprocal block ciphers
W R S R S R S R S R S R S R S R S R S R S R W, where W = whitening, R = a round operation, S = swap
May
11
comment Reciprocal block ciphers
@Melab using a palindromic key schedule as per orlp's answer. I tested it using the AES round as the F-function to build a 256-bit involutional cipher with an 11 rounds and I/O whitening, it works correctly
May
10
answered Reciprocal block ciphers
May
5
answered How openssl padding for AES cfb IV?
May
4
comment where can i learn the basics of AES?
formaestudio.com/rijndaelinspector/archivos/…