mirror of
https://github.com/cryb-to/cryb-to.git
synced 2024-11-27 08:05:42 +00:00
124 lines
3.4 KiB
C
124 lines
3.4 KiB
C
/*-
|
|
* Copyright (c) 2015-2016 Dag-Erling Smørgrav
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. The name of the author may not be used to endorse or promote
|
|
* products derived from this software without specific prior written
|
|
* permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include "cryb/impl.h"
|
|
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
|
|
#include <cryb/assert.h>
|
|
#include <cryb/bitwise.h>
|
|
#include <cryb/endian.h>
|
|
#include <cryb/memset_s.h>
|
|
|
|
#include <cryb/rc4.h>
|
|
|
|
void
|
|
rc4_init(rc4_ctx *ctx, cipher_mode mode CRYB_UNUSED,
|
|
const uint8_t *key, size_t keylen)
|
|
{
|
|
unsigned int i, j;
|
|
uint8_t t;
|
|
|
|
assert(mode == CIPHER_MODE_ENCRYPT || mode == CIPHER_MODE_DECRYPT);
|
|
assert(keylen > 0);
|
|
memset(ctx, 0, sizeof *ctx);
|
|
for (i = 0; i < 256; ++i)
|
|
ctx->s[i] = i;
|
|
for (i = j = 0; i < 256; ++i) {
|
|
j = (j + ctx->s[i] + key[i % keylen]) % 256;
|
|
t = ctx->s[i];
|
|
ctx->s[i] = ctx->s[j];
|
|
ctx->s[j] = t;
|
|
}
|
|
}
|
|
|
|
size_t
|
|
rc4_keystream(rc4_ctx *ctx, uint8_t *ks, size_t len)
|
|
{
|
|
unsigned int i;
|
|
uint8_t t;
|
|
|
|
for (i = 0; i < len; ++i) {
|
|
ctx->i = ctx->i + 1;
|
|
ctx->j = ctx->j + ctx->s[ctx->i];
|
|
t = ctx->s[ctx->i];
|
|
ctx->s[ctx->i] = ctx->s[ctx->j];
|
|
ctx->s[ctx->j] = t;
|
|
t = ctx->s[ctx->i] + ctx->s[ctx->j];
|
|
*ks++ = ctx->s[t];
|
|
}
|
|
return (len);
|
|
}
|
|
|
|
size_t
|
|
rc4_encrypt(rc4_ctx *ctx, const void *vpt, uint8_t *ct, size_t len)
|
|
{
|
|
const uint8_t *pt = vpt;
|
|
unsigned int i;
|
|
uint8_t t, k;
|
|
|
|
for (i = 0; i < len; ++i) {
|
|
ctx->i = ctx->i + 1;
|
|
ctx->j = ctx->j + ctx->s[ctx->i];
|
|
t = ctx->s[ctx->i];
|
|
ctx->s[ctx->i] = ctx->s[ctx->j];
|
|
ctx->s[ctx->j] = t;
|
|
t = ctx->s[ctx->i] + ctx->s[ctx->j];
|
|
k = ctx->s[t];
|
|
*ct++ = *pt++ ^ k;
|
|
}
|
|
return (len);
|
|
}
|
|
|
|
size_t
|
|
rc4_decrypt(rc4_ctx *ctx, const uint8_t *ct, void *vpt, size_t len)
|
|
{
|
|
|
|
return (rc4_encrypt(ctx, ct, vpt, len));
|
|
}
|
|
|
|
void
|
|
rc4_finish(rc4_ctx *ctx)
|
|
{
|
|
|
|
memset_s(ctx, 0, sizeof *ctx, sizeof *ctx);
|
|
}
|
|
|
|
cipher_algorithm rc4_cipher = {
|
|
.name = "rc4",
|
|
.contextlen = sizeof(rc4_ctx),
|
|
.blocklen = 1,
|
|
.keylen = 0,
|
|
.init = (cipher_init_func)rc4_init,
|
|
.keystream = (cipher_keystream_func)rc4_keystream,
|
|
.encrypt = (cipher_encrypt_func)rc4_encrypt,
|
|
.decrypt = (cipher_decrypt_func)rc4_decrypt,
|
|
.finish = (cipher_finish_func)rc4_finish,
|
|
};
|