From 4573438cc5d180ce38bfee3f649b7813fa030e71 Mon Sep 17 00:00:00 2001 From: Paul Duncan Date: Thu, 9 May 2024 01:07:20 -0400 Subject: sha3.c: add internal documentation, s/absorb12/absorb_12/ --- sha3.c | 266 +++++++++++++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 227 insertions(+), 39 deletions(-) (limited to 'sha3.c') diff --git a/sha3.c b/sha3.c index 4b15618..7768c33 100644 --- a/sha3.c +++ b/sha3.c @@ -26,6 +26,13 @@ #include "sha3.h" // available backends +// +// each backend implements a permute_n_() function, which is +// wrapped in a #if/#endif pair below. +// +// there are currently 5 backends, but only 2 of them -- scalar and +// avx512 -- are auto-detected. the remaining three are experimental +// neon backends and are currently slower than the scalar backend. #define BACKEND_AUTO 0 // auto-detect (default) #define BACKEND_SCALAR 1 // scalar backend #define BACKEND_AVX512 2 // AVX-512 backend @@ -700,7 +707,15 @@ static inline uint64x2_t pi_lo_hi(const uint64x2_t a, const uint64x2_t b) { return vextq_u64(c, c, 1); } -// neon keccak permutation with inlined steps +/** + * @brief Neon Keccak permutation. + * + * @param[in,out] s Keccak state (array of 25 64-bit integers). + * @param[in] num_rounds Number of rounds (12 or 24). + * + * @note Experimental Neon backend. Slower than scalar backend and not + * enabled by default. + */ static inline void permute_n_neon(uint64_t a[static 25], const size_t num_rounds) { // Map of Keccak state to 64-bit lanes of 128-bit registers // --------------------------------------------------------- @@ -947,7 +962,16 @@ static inline uint64x2_t pi_lo_hi(const uint64x2_t a, const uint64x2_t b) { return vextq_u64(c, c, 1); } -// diet-neon keccak permutation with inlined steps +/** + * @brief Neon Keccak permutation. + * + * @param[in,out] s Keccak state (array of 25 64-bit integers). + * @param[in] num_rounds Number of rounds (12 or 24). + * + * @note Experimental Neon backend which uses one fewer 64-bit register + * than the "neon" backend. Slower than scalar backend and not enabled + * by default. + */ static inline void permute_n_diet_neon(uint64_t a[static 25], const size_t num_rounds) { // load rows row_t r0, r1, r2, r3, r4; @@ -1096,6 +1120,8 @@ static inline void permute_n_diet_neon(uint64_t a[static 25], const size_t num_r * * @param[in,out] a Keccak state (array of 25 64-bit integers). * @param[in] num_rounds Number of rounds (12 or 24). + * + * @note Slower than scalar backend and not enabled by default. */ static inline void permute_n_hybrid(uint64_t a[static 25], const size_t num_rounds) { uint64_t tmp[25] = { 0 }; @@ -1279,8 +1305,8 @@ static inline void permute_24(uint64_t s[static 25]) { /** * @brief 12 round Keccak permutation. - * @note Only used by TurboSHAKE and KangarooTwelve. * @param[in,out] a Keccak state (array of 25 64-bit integers). + * @note Only used by TurboSHAKE and KangarooTwelve. */ static inline void permute_12(uint64_t s[static 25]) { permute_n(s, 12); @@ -1288,6 +1314,18 @@ static inline void permute_12(uint64_t s[static 25]) { // absorb message into state, return updated byte count // used by `hash_absorb()`, `hash_once()`, and `xof_absorb_raw()` + +/** + * @brief Absorb message into state and return updated byte count. + * + * Used by `hash_once()`, `hash_absorb()`, `xof_absorb_raw()`. + * + * @param[in,out] a Keccak state (array of 25 64-bit integers). + * @param[in] num_bytes Number of absorbed bytes since last permute. + * @param[in] rate Rate of has function. + * @param[in] m Pointer to input message chunk. + * @param[in] m_len Length of input message chunk, in bytes. + */ static inline size_t absorb(sha3_state_t * const a, size_t num_bytes, const size_t rate, const uint8_t *m, size_t m_len) { // absorb aligned chunks if ((num_bytes & 7) == 0 && (((uintptr_t) m) & 7) == 0) { @@ -1345,9 +1383,18 @@ static inline size_t absorb(sha3_state_t * const a, size_t num_bytes, const size return num_bytes; } -// absorb message into xof12 state, return updated byte count -// used by `xof12_absorb_raw()` -static inline size_t absorb12(sha3_state_t * const a, size_t num_bytes, const size_t rate, const uint8_t *m, size_t m_len) { +/** + * @brief Absorb message into XOF12 state and return updated byte count. + * + * Used by `xof12_absorb_raw()`. + * + * @param[in,out] a Keccak state (array of 25 64-bit integers). + * @param[in] num_bytes Number of absorbed bytes since last permute. + * @param[in] rate Rate of hash function. + * @param[in] m Pointer to input message chunk. + * @param[in] m_len Length of input message chunk, in bytes. + */ +static inline size_t absorb_12(sha3_state_t * const a, size_t num_bytes, const size_t rate, const uint8_t *m, size_t m_len) { // absorb aligned chunks if ((num_bytes & 7) == 0 && (((uintptr_t) m) & 7) == 0) { // absorb 32 byte chunks (4 x uint64) @@ -1437,7 +1484,18 @@ static inline size_t absorb12(sha3_state_t * const a, size_t num_bytes, const si // #define RATE(len) (200 - 2 * (len)) -// one-shot sha3 hash. +/** + * @brief One-shot function which hashes the input message and writes + * the digest to the destination buffer. + * + * Used by `sha3_224()`, `sha3_256()`, `sha3_384()` and `sha3_512()`. + * + * @param[in] m Pointer to input message. + * @param[in] m_len Length of input message, in bytes. + * @param[out] dst Pointer to destination buffer. + * @param[in] dst_len Length of destination buffer, in bytes. Used to + * determine the rate of the hash function. + */ static inline void hash_once(const uint8_t *m, size_t m_len, uint8_t * const dst, const size_t dst_len) { // init state sha3_state_t a = { .u64 = { 0 } }; @@ -1457,14 +1515,32 @@ static inline void hash_once(const uint8_t *m, size_t m_len, uint8_t * const dst memcpy(dst, a.u8, dst_len); } -// Initialize iterative hash context. +/** + * @brief Initialize iterative hash context. + * + * Used by `sha3_224_init()`, `sha3_256_init()`, `sha3_384_init()` and + * `sha3_512_init()`. + * + * @param[in,out] hash Hash context. + */ static inline void hash_init(sha3_t * const hash) { memset(hash, 0, sizeof(sha3_t)); } -// Absorb data into iterative hash context. -// -// Returns `false` if the has context has already been finalized. +/** + * @brief Absorb data into iterative hash context. + * + * Used by `sha3_224_absorb()`, `sha3_256_absorb()`, `sha3_384_absorb()` + * and `sha3_512_absorb()`. + * + * @param[in,out] hash Hash context. + * @param[in] rate Hash function rate. + * @param[in] src Pointer to buffer containing chunk of input message. + * @param[in] src_len Length of input message chunk, in bytes. + * + * @return True if data was absorbed, and false if the hash context has + * already been finalized. + */ static inline bool hash_absorb(sha3_t * const hash, const size_t rate, const uint8_t *src, size_t len) { if (hash->finalized) { // hash already finalized, return false @@ -1476,9 +1552,19 @@ static inline bool hash_absorb(sha3_t * const hash, const size_t rate, const uin return true; } -// Finalize iterative hash context. -// -// May be called more than once without affecting the final hash value. +/** + * @brief Finalize iterative hash context. + * + * Used by `sha3_224_final()`, `sha3_256_final()`, `sha3_384_final()` + * and `sha3_512_final()`. + * + * @param[in,out] hash Hash context. + * @param[in] rate Hash function rate. + * @param[in] dst Pointer to destination buffer. + * @param[in] dst_len Length of destination buffer, in bytes. + * + * @note May be called more than once without affecting the final digest value. + */ static inline void hash_final(sha3_t * const hash, const size_t rate, uint8_t * dst, const size_t dst_len) { if (!hash->finalized) { // mark context as final @@ -1525,22 +1611,41 @@ DEF_HASH(256, 32) // sha3-256 DEF_HASH(384, 48) // sha3-384 DEF_HASH(512, 64) // sha3-512 -// initialize xof context +/** + * @brief Initialize XOF context. + * + * @param[in,out] xof XOF context. + */ static inline void xof_init(sha3_xof_t * const xof) { memset(xof, 0, sizeof(sha3_xof_t)); } -// Absorb data into XOF context without checking to see if the -// context has already been squeezed. -// -// Called by `xof_absorb()` and `xof_once()`. +/** + * @brief Absorb data into XOF context without checking to see if the + * context has already been squeezed. + * + * Called by `xof_absorb()` and `xof_once()`. + * + * @param[in,out] xof XOF context. + * @param[in] rate Rate of XOF function. + * @param[in] m Pointer to buffer containing chunk of input message. + * @param[in] m_len Length of input message chunk, in bytes. + */ static inline void xof_absorb_raw(sha3_xof_t * const xof, const size_t rate, const uint8_t *m, size_t m_len) { xof->num_bytes = absorb(&(xof->a), xof->num_bytes, rate, m, m_len); } -// Absorb data into XOF context. -// -// Returns `false` if this context has already been squeezed. +/** + * @brief Absorb data into XOF context. + * + * @param[in,out] xof XOF context. + * @param[in] rate Rate of XOF function. + * @param[in] m Pointer to buffer containing chunk of input message. + * @param[in] m_len Length of input message chunk, in bytes. + * + * @return `true` if the input message chunk was absorbed, or `false` if + * this XOF context has already been squeezed. + */ static inline _Bool xof_absorb(sha3_xof_t * const xof, const size_t rate, const uint8_t * const m, size_t m_len) { // check context state if (xof->squeezing) { @@ -1553,7 +1658,14 @@ static inline _Bool xof_absorb(sha3_xof_t * const xof, const size_t rate, const return true; } -// Finalize absorb, switch mode of XOF context to squeezing. +/** + * @brief Finalize absorb for this XOF context and switch context mode + * from absorbing to squeezing. + * + * @param[in,out] xof XOF context. + * @param[in] rate Rate of XOF function. + * @param[in] pad Padding byte of XOF function. + */ static inline void xof_absorb_done(sha3_xof_t * const xof, const size_t rate, const uint8_t pad) { // append suffix (s6.2) and padding // (note: suffix and padding are ambiguous in spec) @@ -1568,7 +1680,14 @@ static inline void xof_absorb_done(sha3_xof_t * const xof, const size_t rate, co xof->squeezing = true; } -// Squeeze data without checking mode (used by `xof_once()`). +/** + * @brief Squeeze data from XOF context without checking mode. + * + * @param[in,out] xof XOF context. + * @param[in] rate Rate of XOF function. + * @param[out] dst Pointer to destination buffer. + * @param[out] dst_len Length of destination buffer, in bytes. + */ static inline void xof_squeeze_raw(sha3_xof_t * const xof, const size_t rate, uint8_t *dst, size_t dst_len) { if (!xof->num_bytes) { // num_bytes is zero, so we are reading from the start of the @@ -1609,7 +1728,16 @@ static inline void xof_squeeze_raw(sha3_xof_t * const xof, const size_t rate, ui } } -// squeeze data from xof +/** + * @brief Finalize absorb (if necessary) and then squeeze data from this + * XOF context. + * + * @param[in,out] xof XOF context. + * @param[in] rate Rate of XOF function. + * @param[in] pad Padding byte of XOF function. + * @param[out] dst Pointer to destination buffer. + * @param[in] dst_len Length of destination buffer, in bytes. + */ static inline void xof_squeeze(sha3_xof_t * const xof, const size_t rate, const uint8_t pad, uint8_t * const dst, const size_t dst_len) { // check state if (!xof->squeezing) { @@ -1620,7 +1748,16 @@ static inline void xof_squeeze(sha3_xof_t * const xof, const size_t rate, const xof_squeeze_raw(xof, rate, dst, dst_len); } -// one-shot xof absorb and squeeze +/** + * @brief One-shot XOF absorb and squeeze. + * + * @param[in] rate Rate of XOF function. + * @param[in] pad Padding byte of XOF function. + * @param[in] src Pointer to buffer containing input message. + * @param[in] src_len Length of input message, in bytes. + * @param[out] dst Pointer to destination buffer. + * @param[out] dst_len Length of destination buffer, in bytes. + */ static inline void xof_once(const size_t rate, const uint8_t pad, const uint8_t * const src, const size_t src_len, uint8_t * const dst, const size_t dst_len) { // init sha3_xof_t xof; @@ -1634,22 +1771,41 @@ static inline void xof_once(const size_t rate, const uint8_t pad, const uint8_t xof_squeeze_raw(&xof, rate, dst, dst_len); } -// initialize xof12 context +/** + * @brief Initialize XOF12 context. + * + * @param[in,out] xof XOF12 context. + */ static inline void xof12_init(sha3_xof_t * const xof) { memset(xof, 0, sizeof(sha3_xof_t)); } -// Absorb data into XOF12 context without checking to see if the -// context has already been squeezed. -// -// Called by `xof12_absorb()` and `xof12_once()`. +/** + * @brief Absorb data into XOF12 context without checking to see if the + * context has already been squeezed. + * + * Called by `xof12_absorb()` and `xof12_once()`. + * + * @param[in,out] xof XOF12 context. + * @param[in] rate Rate of XOF function. + * @param[in] m Pointer to buffer containing chunk of input message. + * @param[in] m_len Length of input message chunk, in bytes. + */ static inline void xof12_absorb_raw(sha3_xof_t * const xof, const size_t rate, const uint8_t *m, size_t m_len) { - xof->num_bytes = absorb12(&(xof->a), xof->num_bytes, rate, m, m_len); + xof->num_bytes = absorb_12(&(xof->a), xof->num_bytes, rate, m, m_len); } -// Absorb data into XOF context. -// -// Returns `false` if this XOF12 context has already been squeezed. +/** + * @brief Absorb data into XOF12 context. + * + * @param[in,out] xof XOF12 context. + * @param[in] rate Rate of XOF12 function. + * @param[in] m Pointer to buffer containing chunk of input message. + * @param[in] m_len Length of input message chunk, in bytes. + * + * @return `true` if the input message chunk was absorbed, or `false` if + * this XOF context has already been squeezed. + */ static inline _Bool xof12_absorb(sha3_xof_t * const xof, const size_t rate, const uint8_t * const m, size_t m_len) { // check context state if (xof->squeezing) { @@ -1662,7 +1818,14 @@ static inline _Bool xof12_absorb(sha3_xof_t * const xof, const size_t rate, cons return true; } -// Finalize absorb, switch mode of XOF12 context to squeezing. +/** + * @brief Finalize absorb for this XOF12 context and switch context mode + * from absorbing to squeezing. + * + * @param[in,out] xof XOF12 context. + * @param[in] rate Rate of XOF function. + * @param[in] pad Padding byte of XOF function. + */ static inline void xof12_absorb_done(sha3_xof_t * const xof, const size_t rate, const uint8_t pad) { // append suffix (s6.2) and padding // (note: suffix and padding are ambiguous in spec) @@ -1677,7 +1840,14 @@ static inline void xof12_absorb_done(sha3_xof_t * const xof, const size_t rate, xof->squeezing = true; } -// Squeeze data without checking mode (used by `xof12_once()`). +/** + * @brief Squeeze data from XOF12 context without checking mode. + * + * @param[in,out] xof XOF12 context. + * @param[in] rate Rate of XOF12 function. + * @param[out] dst Pointer to destination buffer. + * @param[out] dst_len Length of destination buffer, in bytes. + */ static inline void xof12_squeeze_raw(sha3_xof_t * const xof, const size_t rate, uint8_t *dst, size_t dst_len) { if (!xof->num_bytes) { // num_bytes is zero, so we are reading from the start of the @@ -1718,7 +1888,16 @@ static inline void xof12_squeeze_raw(sha3_xof_t * const xof, const size_t rate, } } -// squeeze data from xof12 context +/** + * @brief Finalize absorb (if necessary) and then squeeze data from this + * XOF12 context. + * + * @param[in,out] xof XOF12 context. + * @param[in] rate Rate of XOF12 function. + * @param[in] pad Padding byte of XOF12 function. + * @param[out] dst Pointer to destination buffer. + * @param[in] dst_len Length of destination buffer, in bytes. + */ static inline void xof12_squeeze(sha3_xof_t * const xof, const size_t rate, const uint8_t pad, uint8_t * const dst, const size_t dst_len) { // check state if (!xof->squeezing) { @@ -1729,7 +1908,16 @@ static inline void xof12_squeeze(sha3_xof_t * const xof, const size_t rate, cons xof12_squeeze_raw(xof, rate, dst, dst_len); } -// one-shot xof12 absorb and squeeze +/** + * @brief One-shot XOF12 absorb and squeeze. + * + * @param[in] rate Rate of XOF12 function. + * @param[in] pad Padding byte of XOF12 function. + * @param[in] src Pointer to buffer containing input message. + * @param[in] src_len Length of input message, in bytes. + * @param[out] dst Pointer to destination buffer. + * @param[out] dst_len Length of destination buffer, in bytes. + */ static inline void xof12_once(const size_t rate, const uint8_t pad, const uint8_t * const src, const size_t src_len, uint8_t * const dst, const size_t dst_len) { // init sha3_xof_t xof; -- cgit v1.2.3