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/* SPDX-License-Identifier: GPL-2.0 OR MIT */
/*
* Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#ifndef _ZINC_CHACHA20_H
#define _ZINC_CHACHA20_H
#include <asm/unaligned.h>
#include <linux/simd.h>
#include <linux/kernel.h>
#include <linux/types.h>
enum {
CHACHA20_NONCE_SIZE = 16,
CHACHA20_KEY_SIZE = 32,
CHACHA20_KEY_WORDS = CHACHA20_KEY_SIZE / sizeof(u32),
CHACHA20_BLOCK_SIZE = 64,
CHACHA20_BLOCK_WORDS = CHACHA20_BLOCK_SIZE / sizeof(u32),
HCHACHA20_NONCE_SIZE = CHACHA20_NONCE_SIZE,
HCHACHA20_KEY_SIZE = CHACHA20_KEY_SIZE
};
enum { /* expand 32-byte k */
CHACHA20_CONSTANT_EXPA = 0x61707865U,
CHACHA20_CONSTANT_ND_3 = 0x3320646eU,
CHACHA20_CONSTANT_2_BY = 0x79622d32U,
CHACHA20_CONSTANT_TE_K = 0x6b206574U
};
struct chacha20_ctx {
union {
u32 state[16];
struct {
u32 constant[4];
u32 key[8];
u32 counter[4];
};
};
};
static inline void chacha20_init(struct chacha20_ctx *ctx,
const u8 key[CHACHA20_KEY_SIZE],
const u64 nonce)
{
ctx->constant[0] = CHACHA20_CONSTANT_EXPA;
ctx->constant[1] = CHACHA20_CONSTANT_ND_3;
ctx->constant[2] = CHACHA20_CONSTANT_2_BY;
ctx->constant[3] = CHACHA20_CONSTANT_TE_K;
ctx->key[0] = get_unaligned_le32(key + 0);
ctx->key[1] = get_unaligned_le32(key + 4);
ctx->key[2] = get_unaligned_le32(key + 8);
ctx->key[3] = get_unaligned_le32(key + 12);
ctx->key[4] = get_unaligned_le32(key + 16);
ctx->key[5] = get_unaligned_le32(key + 20);
ctx->key[6] = get_unaligned_le32(key + 24);
ctx->key[7] = get_unaligned_le32(key + 28);
ctx->counter[0] = 0;
ctx->counter[1] = 0;
ctx->counter[2] = nonce & U32_MAX;
ctx->counter[3] = nonce >> 32;
}
void chacha20(struct chacha20_ctx *ctx, u8 *dst, const u8 *src, u32 len,
simd_context_t *simd_context);
void hchacha20(u32 derived_key[CHACHA20_KEY_WORDS],
const u8 nonce[HCHACHA20_NONCE_SIZE],
const u8 key[HCHACHA20_KEY_SIZE], simd_context_t *simd_context);
#endif /* _ZINC_CHACHA20_H */
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