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author | David Monniaux <david.monniaux@univ-grenoble-alpes.fr> | 2019-01-28 22:10:50 +0100 |
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committer | David Monniaux <david.monniaux@univ-grenoble-alpes.fr> | 2019-01-28 22:10:50 +0100 |
commit | 253446c20b5aa03014fd04bcb21e6fd607a3ac5a (patch) | |
tree | be1b6c9f74d36f0332e7935adbb6a3ab61bbc8b5 /test/monniaux/crypto-algorithms/arcfour.c | |
parent | 88a8995fbbb9242d1f97110e79badd608dd03f6b (diff) | |
download | compcert-kvx-253446c20b5aa03014fd04bcb21e6fd607a3ac5a.tar.gz compcert-kvx-253446c20b5aa03014fd04bcb21e6fd607a3ac5a.zip |
crypto algorithms from https://github.com/B-Con/crypto-algorithms/
Diffstat (limited to 'test/monniaux/crypto-algorithms/arcfour.c')
-rw-r--r-- | test/monniaux/crypto-algorithms/arcfour.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/test/monniaux/crypto-algorithms/arcfour.c b/test/monniaux/crypto-algorithms/arcfour.c new file mode 100644 index 00000000..37a88e10 --- /dev/null +++ b/test/monniaux/crypto-algorithms/arcfour.c @@ -0,0 +1,47 @@ +/********************************************************************* +* Filename: arcfour.c +* Author: Brad Conte (brad AT bradconte.com) +* Copyright: +* Disclaimer: This code is presented "as is" without any guarantees. +* Details: Implementation of the ARCFOUR encryption algorithm. + Algorithm specification can be found here: + * http://en.wikipedia.org/wiki/RC4 +*********************************************************************/ + +/*************************** HEADER FILES ***************************/ +#include <stdlib.h> +#include "arcfour.h" + +/*********************** FUNCTION DEFINITIONS ***********************/ +void arcfour_key_setup(BYTE state[], const BYTE key[], int len) +{ + int i, j; + BYTE t; + + for (i = 0; i < 256; ++i) + state[i] = i; + for (i = 0, j = 0; i < 256; ++i) { + j = (j + state[i] + key[i % len]) % 256; + t = state[i]; + state[i] = state[j]; + state[j] = t; + } +} + +// This does not hold state between calls. It always generates the +// stream starting from the first output byte. +void arcfour_generate_stream(BYTE state[], BYTE out[], size_t len) +{ + int i, j; + size_t idx; + BYTE t; + + for (idx = 0, i = 0, j = 0; idx < len; ++idx) { + i = (i + 1) % 256; + j = (j + state[i]) % 256; + t = state[i]; + state[i] = state[j]; + state[j] = t; + out[idx] = state[(state[i] + state[j]) % 256]; + } +} |