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/*
* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "inner.h"
/* see bearssl_block.h */
void
br_des_ct_cbcdec_init(br_des_ct_cbcdec_keys *ctx,
const void *key, size_t len)
{
ctx->vtable = &br_des_ct_cbcdec_vtable;
ctx->num_rounds = br_des_ct_keysched(ctx->skey, key, len);
if (len == 8) {
br_des_rev_skey(ctx->skey);
} else {
int i;
for (i = 0; i < 48; i += 2) {
uint32_t t;
t = ctx->skey[i];
ctx->skey[i] = ctx->skey[94 - i];
ctx->skey[94 - i] = t;
t = ctx->skey[i + 1];
ctx->skey[i + 1] = ctx->skey[95 - i];
ctx->skey[95 - i] = t;
}
}
}
/* see bearssl_block.h */
void
br_des_ct_cbcdec_run(const br_des_ct_cbcdec_keys *ctx,
void *iv, void *data, size_t len)
{
unsigned char *buf, *ivbuf;
uint32_t sk_exp[288];
br_des_ct_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
ivbuf = iv;
buf = data;
while (len > 0) {
unsigned char tmp[8];
int i;
memcpy(tmp, buf, 8);
br_des_ct_process_block(ctx->num_rounds, sk_exp, buf);
for (i = 0; i < 8; i ++) {
buf[i] ^= ivbuf[i];
}
memcpy(ivbuf, tmp, 8);
buf += 8;
len -= 8;
}
}
/* see bearssl_block.h */
const br_block_cbcdec_class br_des_ct_cbcdec_vtable = {
sizeof(br_des_ct_cbcdec_keys),
8,
3,
(void (*)(const br_block_cbcdec_class **, const void *, size_t))
&br_des_ct_cbcdec_init,
(void (*)(const br_block_cbcdec_class *const *, void *, void *, size_t))
&br_des_ct_cbcdec_run
};
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