1/* $OpenBSD: e_chacha.c,v 1.14 2024/04/09 13:52:41 beck 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 <openssl/opensslconf.h> 19 20#ifndef OPENSSL_NO_CHACHA 21 22#include <openssl/chacha.h> 23#include <openssl/evp.h> 24#include <openssl/objects.h> 25 26#include "evp_local.h" 27 28static int 29chacha_init(EVP_CIPHER_CTX *ctx, const unsigned char *key, 30 const unsigned char *openssl_iv, int enc) 31{ 32 if (key != NULL) 33 ChaCha_set_key((ChaCha_ctx *)ctx->cipher_data, key, 34 EVP_CIPHER_CTX_key_length(ctx) * 8); 35 if (openssl_iv != NULL) { 36 const unsigned char *iv = openssl_iv + 8; 37 const unsigned char *counter = openssl_iv; 38 39 ChaCha_set_iv((ChaCha_ctx *)ctx->cipher_data, iv, counter); 40 } 41 return 1; 42} 43 44static int 45chacha_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, const unsigned char *in, 46 size_t len) 47{ 48 ChaCha((ChaCha_ctx *)ctx->cipher_data, out, in, len); 49 return 1; 50} 51 52static const EVP_CIPHER chacha20_cipher = { 53 .nid = NID_chacha20, 54 .block_size = 1, 55 .key_len = 32, 56 /* 57 * The 16-byte EVP IV is split into 4 little-endian 4-byte words 58 * evpiv[15:12] evpiv[11:8] evpiv[7:4] evpiv[3:0] 59 * iv[1] iv[0] counter[1] counter[0] 60 * and passed as iv[] and counter[] to ChaCha_set_iv(). 61 */ 62 .iv_len = 16, 63 .flags = EVP_CIPH_STREAM_CIPHER | EVP_CIPH_ALWAYS_CALL_INIT | 64 EVP_CIPH_CUSTOM_IV, 65 .init = chacha_init, 66 .do_cipher = chacha_cipher, 67 .ctx_size = sizeof(ChaCha_ctx) 68}; 69 70const EVP_CIPHER * 71EVP_chacha20(void) 72{ 73 return (&chacha20_cipher); 74} 75LCRYPTO_ALIAS(EVP_chacha20); 76 77#endif 78