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