105 lines
3.1 KiB
C
105 lines
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* Common values and helper functions for the ChaCha and XChaCha stream ciphers.
|
|
*
|
|
* XChaCha extends ChaCha's nonce to 192 bits, while provably retaining ChaCha's
|
|
* security. Here they share the same key size, tfm context, and setkey
|
|
* function; only their IV size and encrypt/decrypt function differ.
|
|
*
|
|
* The ChaCha paper specifies 20, 12, and 8-round variants. In general, it is
|
|
* recommended to use the 20-round variant ChaCha20. However, the other
|
|
* variants can be needed in some performance-sensitive scenarios. The generic
|
|
* ChaCha code currently allows only the 20 and 12-round variants.
|
|
*/
|
|
|
|
#ifndef _CRYPTO_CHACHA_H
|
|
#define _CRYPTO_CHACHA_H
|
|
|
|
#include <asm/unaligned.h>
|
|
#include <linux/types.h>
|
|
|
|
/* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */
|
|
#define CHACHA_IV_SIZE 16
|
|
|
|
#define CHACHA_KEY_SIZE 32
|
|
#define CHACHA_BLOCK_SIZE 64
|
|
#define CHACHAPOLY_IV_SIZE 12
|
|
|
|
#define CHACHA_STATE_WORDS (CHACHA_BLOCK_SIZE / sizeof(u32))
|
|
|
|
/* 192-bit nonce, then 64-bit stream position */
|
|
#define XCHACHA_IV_SIZE 32
|
|
|
|
void chacha_block_generic(u32 *state, u8 *stream, int nrounds);
|
|
static inline void chacha20_block(u32 *state, u8 *stream)
|
|
{
|
|
chacha_block_generic(state, stream, 20);
|
|
}
|
|
|
|
void hchacha_block_arch(const u32 *state, u32 *out, int nrounds);
|
|
void hchacha_block_generic(const u32 *state, u32 *out, int nrounds);
|
|
|
|
static inline void hchacha_block(const u32 *state, u32 *out, int nrounds)
|
|
{
|
|
if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA))
|
|
hchacha_block_arch(state, out, nrounds);
|
|
else
|
|
hchacha_block_generic(state, out, nrounds);
|
|
}
|
|
|
|
static inline void chacha_init_consts(u32 *state)
|
|
{
|
|
state[0] = 0x61707865; /* "expa" */
|
|
state[1] = 0x3320646e; /* "nd 3" */
|
|
state[2] = 0x79622d32; /* "2-by" */
|
|
state[3] = 0x6b206574; /* "te k" */
|
|
}
|
|
|
|
void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv);
|
|
static inline void chacha_init_generic(u32 *state, const u32 *key, const u8 *iv)
|
|
{
|
|
chacha_init_consts(state);
|
|
state[4] = key[0];
|
|
state[5] = key[1];
|
|
state[6] = key[2];
|
|
state[7] = key[3];
|
|
state[8] = key[4];
|
|
state[9] = key[5];
|
|
state[10] = key[6];
|
|
state[11] = key[7];
|
|
state[12] = get_unaligned_le32(iv + 0);
|
|
state[13] = get_unaligned_le32(iv + 4);
|
|
state[14] = get_unaligned_le32(iv + 8);
|
|
state[15] = get_unaligned_le32(iv + 12);
|
|
}
|
|
|
|
static inline void chacha_init(u32 *state, const u32 *key, const u8 *iv)
|
|
{
|
|
if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA))
|
|
chacha_init_arch(state, key, iv);
|
|
else
|
|
chacha_init_generic(state, key, iv);
|
|
}
|
|
|
|
void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src,
|
|
unsigned int bytes, int nrounds);
|
|
void chacha_crypt_generic(u32 *state, u8 *dst, const u8 *src,
|
|
unsigned int bytes, int nrounds);
|
|
|
|
static inline void chacha_crypt(u32 *state, u8 *dst, const u8 *src,
|
|
unsigned int bytes, int nrounds)
|
|
{
|
|
if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA))
|
|
chacha_crypt_arch(state, dst, src, bytes, nrounds);
|
|
else
|
|
chacha_crypt_generic(state, dst, src, bytes, nrounds);
|
|
}
|
|
|
|
static inline void chacha20_crypt(u32 *state, u8 *dst, const u8 *src,
|
|
unsigned int bytes)
|
|
{
|
|
chacha_crypt(state, dst, src, bytes, 20);
|
|
}
|
|
|
|
#endif /* _CRYPTO_CHACHA_H */
|