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