1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * The ChaCha stream cipher (RFC7539)
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2015 Martin Willi
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/kernel.h>
9*4882a593Smuzhiyun #include <linux/export.h>
10*4882a593Smuzhiyun #include <linux/module.h>
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #include <crypto/algapi.h> // for crypto_xor_cpy
13*4882a593Smuzhiyun #include <crypto/chacha.h>
14*4882a593Smuzhiyun
chacha_crypt_generic(u32 * state,u8 * dst,const u8 * src,unsigned int bytes,int nrounds)15*4882a593Smuzhiyun void chacha_crypt_generic(u32 *state, u8 *dst, const u8 *src,
16*4882a593Smuzhiyun unsigned int bytes, int nrounds)
17*4882a593Smuzhiyun {
18*4882a593Smuzhiyun /* aligned to potentially speed up crypto_xor() */
19*4882a593Smuzhiyun u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long));
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun while (bytes >= CHACHA_BLOCK_SIZE) {
22*4882a593Smuzhiyun chacha_block_generic(state, stream, nrounds);
23*4882a593Smuzhiyun crypto_xor_cpy(dst, src, stream, CHACHA_BLOCK_SIZE);
24*4882a593Smuzhiyun bytes -= CHACHA_BLOCK_SIZE;
25*4882a593Smuzhiyun dst += CHACHA_BLOCK_SIZE;
26*4882a593Smuzhiyun src += CHACHA_BLOCK_SIZE;
27*4882a593Smuzhiyun }
28*4882a593Smuzhiyun if (bytes) {
29*4882a593Smuzhiyun chacha_block_generic(state, stream, nrounds);
30*4882a593Smuzhiyun crypto_xor_cpy(dst, src, stream, bytes);
31*4882a593Smuzhiyun }
32*4882a593Smuzhiyun }
33*4882a593Smuzhiyun EXPORT_SYMBOL(chacha_crypt_generic);
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun MODULE_LICENSE("GPL");
36