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/* $OpenBSD: chacha.c,v 1.7 2015/12/09 14:07:55 bcook Exp $ */
/*
* Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <stdint.h>
#include <chacha.h>
#include "chacha-merged.c"
void
ChaCha_set_key(ChaCha_ctx *ctx, const unsigned char *key, uint32_t keybits)
{
chacha_keysetup((chacha_ctx *)ctx, key, keybits);
ctx->unused = 0;
}
void
ChaCha_set_iv(ChaCha_ctx *ctx, const unsigned char *iv,
const unsigned char *counter)
{
chacha_ivsetup((chacha_ctx *)ctx, iv, counter);
ctx->unused = 0;
}
void
ChaCha(ChaCha_ctx *ctx, unsigned char *out, const unsigned char *in, size_t len)
{
unsigned char *k;
int i, l;
/* Consume remaining keystream, if any exists. */
if (ctx->unused > 0) {
k = ctx->ks + 64 - ctx->unused;
l = (len > ctx->unused) ? ctx->unused : len;
for (i = 0; i < l; i++)
*(out++) = *(in++) ^ *(k++);
ctx->unused -= l;
len -= l;
}
chacha_encrypt_bytes((chacha_ctx *)ctx, in, out, (uint32_t)len);
}
void
CRYPTO_chacha_20(unsigned char *out, const unsigned char *in, size_t len,
const unsigned char key[32], const unsigned char iv[8], uint64_t counter)
{
struct chacha_ctx ctx;
/*
* chacha_ivsetup expects the counter to be in u8. Rather than
* converting size_t to u8 and then back again, pass a counter of
* NULL and manually assign it afterwards.
*/
chacha_keysetup(&ctx, key, 256);
chacha_ivsetup(&ctx, iv, NULL);
if (counter != 0) {
ctx.input[12] = (uint32_t)counter;
ctx.input[13] = (uint32_t)(counter >> 32);
}
chacha_encrypt_bytes(&ctx, in, out, (uint32_t)len);
}
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