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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103/* 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 <linux/unaligned.h>#include <linux/string.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_KEY_WORDS 8#define CHACHA_STATE_WORDS 16#define HCHACHA_OUT_WORDS 8
/* 192-bit nonce, then 64-bit stream position */#define XCHACHA_IV_SIZE 32
struct chacha_state { u32 x[CHACHA_STATE_WORDS];};
void chacha_block_generic(struct chacha_state *state, u8 out[at_least CHACHA_BLOCK_SIZE], int nrounds);static inline void chacha20_block(struct chacha_state *state, u8 out[at_least CHACHA_BLOCK_SIZE]){ chacha_block_generic(state, out, 20);}
void hchacha_block_generic(const struct chacha_state *state, u32 out[at_least HCHACHA_OUT_WORDS], int nrounds);
void hchacha_block(const struct chacha_state *state, u32 out[at_least HCHACHA_OUT_WORDS], int nrounds);
enum chacha_constants { /* expand 32-byte k */ CHACHA_CONSTANT_EXPA = 0x61707865U, CHACHA_CONSTANT_ND_3 = 0x3320646eU, CHACHA_CONSTANT_2_BY = 0x79622d32U, CHACHA_CONSTANT_TE_K = 0x6b206574U};
static inline void chacha_init_consts(struct chacha_state *state){ state->x[0] = CHACHA_CONSTANT_EXPA; state->x[1] = CHACHA_CONSTANT_ND_3; state->x[2] = CHACHA_CONSTANT_2_BY; state->x[3] = CHACHA_CONSTANT_TE_K;}
static inline void chacha_init(struct chacha_state *state, const u32 key[at_least CHACHA_KEY_WORDS], const u8 iv[at_least CHACHA_IV_SIZE]){ chacha_init_consts(state); state->x[4] = key[0]; state->x[5] = key[1]; state->x[6] = key[2]; state->x[7] = key[3]; state->x[8] = key[4]; state->x[9] = key[5]; state->x[10] = key[6]; state->x[11] = key[7]; state->x[12] = get_unaligned_le32(iv + 0); state->x[13] = get_unaligned_le32(iv + 4); state->x[14] = get_unaligned_le32(iv + 8); state->x[15] = get_unaligned_le32(iv + 12);}
void chacha_crypt(struct chacha_state *state, u8 *dst, const u8 *src, size_t bytes, int nrounds);
static inline void chacha20_crypt(struct chacha_state *state, u8 *dst, const u8 *src, size_t bytes){ chacha_crypt(state, dst, src, bytes, 20);}
static inline void chacha_zeroize_state(struct chacha_state *state){ memzero_explicit(state, sizeof(*state));}
#endif /* _CRYPTO_CHACHA_H */