diff options
author | Niels Möller <nisse@lysator.liu.se> | 2000-10-22 22:27:59 +0200 |
---|---|---|
committer | Niels Möller <nisse@lysator.liu.se> | 2000-10-22 22:27:59 +0200 |
commit | ec7611d74a6f7a740f8720e62d92efecb42da521 (patch) | |
tree | 47115abd5ba3e833806bbd3c62904975971e8ee0 /arcfour.c | |
parent | ed59fe97649b20e2ba0c31bbeb7822cbc593fc20 (diff) | |
download | nettle-ec7611d74a6f7a740f8720e62d92efecb42da521.tar.gz |
* src/symmetric/arcfour.c (arcfour_crypt): Changed argument order.
(arcfour_set_key): Likewise.
(arcfour_stream): New function.
(arcfour_update_key): New function.
(arcfour_init): New function.
Rev: src/symmetric/arcfour.c:1.5
Rev: src/symmetric/include/arcfour.h:1.2
Diffstat (limited to 'arcfour.c')
-rw-r--r-- | arcfour.c | 53 |
1 files changed, 49 insertions, 4 deletions
@@ -34,7 +34,52 @@ RCSID("$Id$"); #define SWAP(a,b) do { int _t = a; a = b; b = _t; } while(0) -void arcfour_set_key(struct arcfour_ctx *ctx, const UINT8 *key, UINT32 len) +void arcfour_init(struct arcfour_ctx *ctx) +{ + unsigned i; + + /* Initialize context */ + + for (i = 0; i<256; i++) + ctx->S[i] = i; +} + +void arcfour_update_key(struct arcfour_ctx *ctx, + UINT32 length, const UINT8 *key) +{ + register UINT8 i = ctx->i; + register UINT8 j = ctx->j; + + unsigned k; + + for (k = 0; k<length; k++) + { + i++; i &= 0xff; + j += ctx->S[i] + key[k]; j &= 0xff; + SWAP(ctx->S[i], ctx->S[j]); + } + ctx->i = i; ctx->j = j; +} + +void arcfour_stream(struct arcfour_ctx *ctx, + UINT32 length, UINT8 *dest) +{ + register UINT8 i = ctx->i; + register UINT8 j = ctx->j; + unsigned k; + + for (k = 0; k<length; k++) + { + i++; i &= 0xff; + j += ctx->S[i]; j &= 0xff; + SWAP(ctx->S[i], ctx->S[j]); + dest[k] = ctx->S[ (ctx->S[i] + ctx->S[j]) & 0xff ]; + } + + ctx->i = i; ctx->j = j; +} + +void arcfour_set_key(struct arcfour_ctx *ctx, UINT32 length, const UINT8 *key) { register UINT8 j; /* Depends on the eight-bitness of these variables. */ unsigned i; @@ -49,19 +94,19 @@ void arcfour_set_key(struct arcfour_ctx *ctx, const UINT8 *key, UINT32 len) do { j += ctx->S[i] + key[k]; SWAP(ctx->S[i], ctx->S[j]); - k = (k+1) % len; /* Repeat key if needed */ + k = (k+1) % length; /* Repeat key if needed */ } while(++i < 256); ctx->i = ctx->j = 0; } void arcfour_crypt(struct arcfour_ctx *ctx, UINT8 *dest, - const UINT8 *src, UINT32 len) + UINT32 length, const UINT8 *src) { register UINT8 i, j; i = ctx->i; j = ctx->j; - while(len--) + while(length--) { i++; i &= 0xff; j += ctx->S[i]; j &= 0xff; |