1 /* $OpenBSD: chacha.c,v 1.7 2015/12/09 14:07:55 bcook Exp $ */ 2 /* 3 * Copyright (c) 2014 Joel Sing <jsing@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include <stdint.h> 19 20 #include <openssl/chacha.h> 21 22 #include "chacha-merged.c" 23 24 void 25 ChaCha_set_key(ChaCha_ctx *ctx, const unsigned char *key, uint32_t keybits) 26 { 27 chacha_keysetup((chacha_ctx *)ctx, key, keybits); 28 ctx->unused = 0; 29 } 30 31 void 32 ChaCha_set_iv(ChaCha_ctx *ctx, const unsigned char *iv, 33 const unsigned char *counter) 34 { 35 chacha_ivsetup((chacha_ctx *)ctx, iv, counter); 36 ctx->unused = 0; 37 } 38 39 void 40 ChaCha(ChaCha_ctx *ctx, unsigned char *out, const unsigned char *in, size_t len) 41 { 42 unsigned char *k; 43 int i, l; 44 45 /* Consume remaining keystream, if any exists. */ 46 if (ctx->unused > 0) { 47 k = ctx->ks + 64 - ctx->unused; 48 l = (len > ctx->unused) ? ctx->unused : len; 49 for (i = 0; i < l; i++) 50 *(out++) = *(in++) ^ *(k++); 51 ctx->unused -= l; 52 len -= l; 53 } 54 55 chacha_encrypt_bytes((chacha_ctx *)ctx, in, out, (uint32_t)len); 56 } 57 58 void 59 CRYPTO_chacha_20(unsigned char *out, const unsigned char *in, size_t len, 60 const unsigned char key[32], const unsigned char iv[8], uint64_t counter) 61 { 62 struct chacha_ctx ctx; 63 64 /* 65 * chacha_ivsetup expects the counter to be in u8. Rather than 66 * converting size_t to u8 and then back again, pass a counter of 67 * NULL and manually assign it afterwards. 68 */ 69 chacha_keysetup(&ctx, key, 256); 70 chacha_ivsetup(&ctx, iv, NULL); 71 if (counter != 0) { 72 ctx.input[12] = (uint32_t)counter; 73 ctx.input[13] = (uint32_t)(counter >> 32); 74 } 75 76 chacha_encrypt_bytes(&ctx, in, out, (uint32_t)len); 77 } 78