From 4ad0ff5bf5aded277263515b7683fd9b610c1fe4 Mon Sep 17 00:00:00 2001 From: Paul Duncan Date: Mon, 4 Sep 2023 11:32:34 -0400 Subject: sha3.h: document cshake{128,256}(), cshake{128,256}_xof_{init,absorb,squeeze}() --- sha3.h | 141 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 129 insertions(+), 12 deletions(-) diff --git a/sha3.h b/sha3.h index 1545f25..5d574a1 100644 --- a/sha3.h +++ b/sha3.h @@ -17,11 +17,11 @@ typedef union { uint64_t u64[25]; } sha3_state_t; -// XOF state +// Internal XOF state typedef struct { - size_t num_bytes; - sha3_state_t a; - _Bool squeezing; + size_t num_bytes; // number of bytes absorbed + sha3_state_t a; // internal state + _Bool squeezing; // mode (absorbing or squeezing) } sha3_xof_t; /** @@ -102,7 +102,7 @@ void shake128_xof_init(sha3_xof_t * const xof); * context `xof`. Can be called iteratively to absorb input data in * chunks. * - * @param[in] xof SHAKE128 XOF context. + * @param[in/out] xof SHAKE128 XOF context. * @param[in] m Input data. * @param[in] len Input data length, in bytes. * @@ -115,7 +115,7 @@ _Bool shake128_xof_absorb(sha3_xof_t *xof, const uint8_t *m, const size_t len); * XOF context `xof`. Can be called iteratively to squeeze output data * in chunks. * - * @param[in] xof SHAKE128 XOF context. + * @param[in/out] xof SHAKE128 XOF context. * @param[out] dst Destination buffer. * @param[in] len Destination buffer length, in bytes. */ @@ -145,7 +145,7 @@ void shake256_xof_init(sha3_xof_t *xof); * context `xof`. Can be called iteratively to absorb input data in * chunks. * - * @param[in] xof SHAKE256 XOF context. + * @param[in/out] xof SHAKE256 XOF context. * @param[in] m Input data. * @param[in] len Input data length, in bytes. * @@ -158,7 +158,7 @@ _Bool shake256_xof_absorb(sha3_xof_t *xof, const uint8_t *m, const size_t len); * XOF context `xof`. Can be called iteratively to squeeze output data * in chunks. * - * @param[in] xof SHAKE256 XOF context. + * @param[in/out] xof SHAKE256 XOF context. * @param[out] dst Destination buffer. * @param[in] len Destination buffer length, in bytes. */ @@ -184,15 +184,132 @@ typedef struct { const size_t custom_len; // length of customization string, in bytes } cshake_params_t; -void cshake128(const cshake_params_t params, const uint8_t *msg, const size_t msg_len, uint8_t *dst, const size_t dst_len); -void cshake256(const cshake_params_t params, const uint8_t *msg, const size_t msg_len, uint8_t *dst, const size_t dst_len); +/** + * Initialize internal cSHAKE128 (customizable SHAKE128, as defined in + * section 3 of NIST SP 800-185) context with customization parameters + * `params`, absorb data in buffer `src` of length `src_len` bytes into + * internal context, then squeeze `dst_len` bytes of output into + * destination buffer `dst`. + * + * Note: cSHAKE is used to implement the hash and extendable output + * functions (XOF) defined in NIST SP 800-185 and should generally not + * be used directly. + * + * @param[in] params cSHAKE customization parameters. + * @param[in] src Input data buffer. + * @param[in] src_len Input data buffer length, in bytes. + * @param[out] dst Destination buffer. + * @param[in] len Destination buffer length, in bytes. + */ +void cshake128(const cshake_params_t params, const uint8_t *src, const size_t src_len, uint8_t *dst, const size_t dst_len); + +/** + * Initialize internal cSHAKE256 (customizable SHAKE256, as defined in + * section 3 of NIST SP 800-185) context with customization parameters + * `params`, absorb data in buffer `src` of length `src_len` bytes into + * internal context, then squeeze `dst_len` bytes of output into + * destination buffer `dst`. + * + * Note: cSHAKE is used to implement the hash and extendable output + * functions (XOF) defined in NIST SP 800-185 and should generally not + * be used directly. + * + * @param[in] params cSHAKE customization parameters. + * @param[in] src Input data buffer. + * @param[in] src_len Input data buffer length, in bytes. + * @param[out] dst Destination buffer. + * @param[in] len Destination buffer length, in bytes. + */ +void cshake256(const cshake_params_t params, const uint8_t *src, const size_t src_len, uint8_t *dst, const size_t dst_len); +/** + * Initialize cSHAKE128 (customizable SHAKE128, as defined in section 3 of + * NIST SP 800-185) XOF context with customization parameters `params`. + * + * Note: cSHAKE is used to implement the hash and extendable output + * functions (XOF) defined in NIST SP 800-185 and should generally not + * be used directly. + * + * @param[out] xof cSHAKE128 context. + * @param[in] params cSHAKE128 customization parameters. + */ void cshake128_xof_init(sha3_xof_t *xof, const cshake_params_t params); -_Bool cshake128_xof_absorb(sha3_xof_t *xof, const uint8_t *msg, const size_t len); + +/** + * Absorb data in buffer `src` of length `len` bytes into cSHAKE128 XOF + * context `xof`. Can be called iteratively to absorb input data in + * chunks. + * + * Note: cSHAKE is used to implement the hash and extendable output + * functions (XOF) defined in NIST SP 800-185 and should generally not + * be used directly. + * + * @param[in/out] xof cSHAKE128 context. + * @param[in] msg Input data buffer. + * @param[in] len Input data buffer length, in bytes. + * + * @return True if data was absorbed, and false otherwise (e.g., if context has already been squeezed). + */ +_Bool cshake128_xof_absorb(sha3_xof_t *xof, const uint8_t *src, const size_t len); + +/** + * Squeeze `dst_len` bytes data into output buffer `dst` from cSHAKE128 + * context XOF context `xof`. Can be called iteratively to squeeze + * output data in chunks. + * + * Note: cSHAKE is used to implement the hash and extendable output + * functions (XOF) defined in NIST SP 800-185 and should generally not + * be used directly. + * + * @param[in/out] xof cSHAKE128 context. + * @param[out] dst Destination buffer. + * @param[in] len Destination buffer length, in bytes. + */ void cshake128_xof_squeeze(sha3_xof_t *xof, uint8_t *dst, const size_t len); +/** + * Initialize cSHAKE256 (customizable SHAKE256, as defined in section 3 of + * NIST SP 800-185) XOF context with customization parameters `params`. + * + * Note: cSHAKE is used to implement the hash and extendable output + * functions (XOF) defined in NIST SP 800-185 and should generally not + * be used directly. + * + * @param[out] xof cSHAKE256 context. + * @param[in] params cSHAKE256 customization parameters. + */ void cshake256_xof_init(sha3_xof_t *xof, const cshake_params_t params); -_Bool cshake256_xof_absorb(sha3_xof_t *xof, const uint8_t *msg, const size_t len); + +/** + * Absorb data in buffer `src` of length `len` bytes into cSHAKE256 XOF + * context `xof`. Can be called iteratively to absorb input data in + * chunks. + * + * Note: cSHAKE is used to implement the hash and extendable output + * functions (XOF) defined in NIST SP 800-185 and should generally not + * be used directly. + * + * @param[in/out] xof cSHAKE256 context. + * @param[in] msg Input data buffer. + * @param[in] len Input data buffer length, in bytes. + * + * @return True if data was absorbed, and false otherwise (e.g., if context has already been squeezed). + */ +_Bool cshake256_xof_absorb(sha3_xof_t *xof, const uint8_t *src, const size_t len); + +/** + * Squeeze `dst_len` bytes data into output buffer `dst` from cSHAKE256 + * context XOF context `xof`. Can be called iteratively to squeeze + * output data in chunks. + * + * Note: cSHAKE is used to implement the hash and extendable output + * functions (XOF) defined in NIST SP 800-185 and should generally not + * be used directly. + * + * @param[in/out] xof cSHAKE256 context. + * @param[out] dst Destination buffer. + * @param[in] len Destination buffer length, in bytes. + */ void cshake256_xof_squeeze(sha3_xof_t *xof, uint8_t *dst, const size_t len); typedef struct { -- cgit v1.2.3