1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * The ChaCha stream cipher (RFC7539) 4 * 5 * Copyright (C) 2015 Martin Willi 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/export.h> 10 #include <linux/module.h> 11 12 #include <crypto/algapi.h> // for crypto_xor_cpy 13 #include <crypto/chacha.h> 14 15 void chacha_crypt_generic(u32 *state, u8 *dst, const u8 *src, 16 unsigned int bytes, int nrounds) 17 { 18 /* aligned to potentially speed up crypto_xor() */ 19 u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long)); 20 21 while (bytes >= CHACHA_BLOCK_SIZE) { 22 chacha_block_generic(state, stream, nrounds); 23 crypto_xor_cpy(dst, src, stream, CHACHA_BLOCK_SIZE); 24 bytes -= CHACHA_BLOCK_SIZE; 25 dst += CHACHA_BLOCK_SIZE; 26 src += CHACHA_BLOCK_SIZE; 27 } 28 if (bytes) { 29 chacha_block_generic(state, stream, nrounds); 30 crypto_xor_cpy(dst, src, stream, bytes); 31 } 32 } 33 EXPORT_SYMBOL(chacha_crypt_generic); 34 35 MODULE_DESCRIPTION("ChaCha stream cipher (RFC7539)"); 36 MODULE_LICENSE("GPL"); 37