mirror of
https://github.com/cryb-to/cryb-to.git
synced 2024-12-04 03:25:43 +00:00
1073dceed9
We now have separate encryption and decryption methods, and can process an arbitrary amount of plaintext or ciphertext per call, rounded down to the block size (if applicable). For stream ciphers, we also have a keystream method which fills the provided buffer with an arbitrary amount of keystream (once again, rounded down if applicable).
121 lines
3.3 KiB
C
121 lines
3.3 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/bitwise.h>
|
|
#include <cryb/endian.h>
|
|
#include <cryb/memset_s.h>
|
|
|
|
#include <cryb/rc4.h>
|
|
|
|
void
|
|
rc4_init(rc4_ctx *ctx, cipher_mode mode, const uint8_t *key, size_t keylen)
|
|
{
|
|
unsigned int i, j;
|
|
uint8_t t;
|
|
|
|
(void)mode;
|
|
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 *in, void *out, size_t len)
|
|
{
|
|
|
|
return (rc4_encrypt(ctx, in, out, 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,
|
|
};
|