sparkle-hash.h

/*
 * Copyright (C) 2021 Southern Storm Software, Pty Ltd.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
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 * The above copyright notice and this permission notice shall be included
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#ifndef LWCRYPTO_SPARKLE_HASH_H
#define LWCRYPTO_SPARKLE_HASH_H

#include <stddef.h>

/**
 * \file sparkle-hash.h
 * \brief Hash algorithms based on the SPARKLE permutation.
 *
 * SPARKLE is a family of encryption and hash algorithms that are based
 * around the SPARKLE permutation.  There are three versions of the
 * permutation with 256-bit, 384-bit, and 512-bit state sizes.
 * The hash algorithms in the family are:
 *
 * \li Esch256 hash algorithm with a 256-bit digest output.  This is the
 * primary hash algorithm in the family.
 * \li Esch384 hash algorithm with a 384-bit digest output.
 * \li XOEsch256 extensible output function based on Esch256.
 * \li XOEsch384 extensible output function based on Esch384.
 *
 * References: https://www.cryptolux.org/index.php/Sparkle
 */

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief Size of the hash output for Esch256.
 */
#define ESCH_256_HASH_SIZE 32

/**
 * \brief Rate at which bytes are processed by Esch256 and XOEsch256.
 */
#define ESCH_256_RATE 16

/**
 * \brief Size of the hash output for Esch384.
 */
#define ESCH_384_HASH_SIZE 48

/**
 * \brief Rate at which bytes are processed by Esch384 and XOEsch384.
 */
#define ESCH_384_RATE 16

/**
 * \brief State information for the Esch256 incremental hash mode and the
 * XOEsch256 increment XOF mode.
 */
typedef union
{
    struct {
        unsigned char state[48];    /**< Current hash state */
        unsigned char block[16];    /**< Partial input data block */
        unsigned char count;        /**< Number of bytes in the current block */
        unsigned char mode;         /**< Hash mode: absorb or squeeze */
    } s;                            /**< State */
    unsigned long long align;       /**< For alignment of this structure */

} esch_256_hash_state_t;

/**
 * \brief State information for the Esch384 incremental hash mod ande the
 * XOEsch384 increment XOF mode.
 */
typedef union
{
    struct {
        unsigned char state[64];    /**< Current hash state */
        unsigned char block[16];    /**< Partial input data block */
        unsigned char count;        /**< Number of bytes in the current block */
        unsigned char mode;         /**< Hash mode: absorb or squeeze */
    } s;                            /**< State */
    unsigned long long align;       /**< For alignment of this structure */

} esch_384_hash_state_t;

/**
 * \brief Hashes a block of input data with Esch256 to generate a hash value.
 *
 * \param out Buffer to receive the hash output which must be at least
 * ESCH_256_HASH_SIZE bytes in length.
 * \param in Points to the input data to be hashed.
 * \param inlen Length of the input data in bytes.
 *
 * \return Returns zero on success or -1 if there was an error in the
 * parameters.
 */
int esch_256_hash(unsigned char *out, const unsigned char *in, size_t inlen);

/**
 * \brief Hashes a block of input data with XOEsch256 to generate an
 * XOF output value.
 *
 * \param out Buffer to receive the hash output which must be at least
 * ESCH_256_HASH_SIZE bytes in length.
 * \param in Points to the input data to be hashed.
 * \param inlen Length of the input data in bytes.
 *
 * \return Returns zero on success or -1 if there was an error in the
 * parameters.
 */
int esch_256_xof(unsigned char *out, const unsigned char *in, size_t inlen);

/**
 * \brief Initializes the state for an Esch256 hashing or a XOEsch256
 * XOF operation.
 *
 * \param state State to be initialized.
 *
 * \sa esch_256_hash_update(), esch_256_hash_finalize(), esch_256_hash()
 */
void esch_256_hash_init(esch_256_hash_state_t *state);

/**
 * \brief Updates an Esch256 or XOEsch256 state with more input data.
 *
 * \param state State to be updated.
 * \param in Points to the input data to be incorporated into the state.
 * \param inlen Length of the input data to be incorporated into the state.
 *
 * \sa esch_256_hash_init(), esch_256_hash_finalize(), esch_256_hash_squeeze()
 */
void esch_256_hash_update
    (esch_256_hash_state_t *state, const unsigned char *in, size_t inlen);

/**
 * \brief Returns the final hash value from an Esch256 hashing operation.
 *
 * \param state State to be finalized.
 * \param out Points to the output buffer to receive the 32-byte hash value.
 *
 * This function is intended for generating output from the Esch256
 * hashing mode.  Use esch_256_hash_squeeze() instead to generate XOF data.
 *
 * \sa esch_256_hash_init(), esch_256_hash_update(), esch_256_hash_squeeze()
 */
void esch_256_hash_finalize
    (esch_256_hash_state_t *state, unsigned char *out);

/**
 * \brief Squeezes output data from a XOEsch256 XOF state.
 *
 * \param state State to squeeze the output data from.
 * \param out Points to the output buffer to receive the squeezed data.
 * \param outlen Number of bytes of data to squeeze out of the state.
 *
 * \sa esch_256_hash_init(), esch_256_hash_update()
 */
void esch_256_hash_squeeze
    (esch_256_hash_state_t *state, unsigned char *out, size_t outlen);

/**
 * \brief Hashes a block of input data with Esch384 to generate a hash value.
 *
 * \param out Buffer to receive the hash output which must be at least
 * ESCH_384_HASH_SIZE bytes in length.
 * \param in Points to the input data to be hashed.
 * \param inlen Length of the input data in bytes.
 *
 * \return Returns zero on success or -1 if there was an error in the
 * parameters.
 */
int esch_384_hash(unsigned char *out, const unsigned char *in, size_t inlen);

/**
 * \brief Hashes a block of input data with XOEsch384 to generate an
 * XOF output value.
 *
 * \param out Buffer to receive the hash output which must be at least
 * ESCH_384_HASH_SIZE bytes in length.
 * \param in Points to the input data to be hashed.
 * \param inlen Length of the input data in bytes.
 *
 * \return Returns zero on success or -1 if there was an error in the
 * parameters.
 */
int esch_384_xof(unsigned char *out, const unsigned char *in, size_t inlen);

/**
 * \brief Initializes the state for an Esch384 hashing or a XOEsch384
 * XOF operation.
 *
 * \param state State to be initialized.
 *
 * \sa esch_384_hash_update(), esch_384_hash_finalize(), esch_384_hash()
 */
void esch_384_hash_init(esch_384_hash_state_t *state);

/**
 * \brief Updates an Esch384 state with more input data.
 *
 * \param state State to be updated.
 * \param in Points to the input data to be incorporated into the state.
 * \param inlen Length of the input data to be incorporated into the state.
 *
 * \sa esch_384_hash_init(), esch_384_hash_finalize(), esch_384_hash_squeeze()
 */
void esch_384_hash_update
    (esch_384_hash_state_t *state, const unsigned char *in, size_t inlen);

/**
 * \brief Returns the final hash value from an Esch384 hashing operation.
 *
 * \param state State to be finalized.
 * \param out Points to the output buffer to receive the 48-byte hash value.
 *
 * This function is intended for generating output from the Esch384
 * hashing mode.  Use esch_384_hash_squeeze() instead to generate XOF data.
 *
 * \sa esch_384_hash_init(), esch_384_hash_update(), esch_384_hash_squeeze()
 */
void esch_384_hash_finalize
    (esch_384_hash_state_t *state, unsigned char *out);

/**
 * \brief Squeezes output data from a XOEsch384 XOF state.
 *
 * \param state State to squeeze the output data from.
 * \param out Points to the output buffer to receive the squeezed data.
 * \param outlen Number of bytes of data to squeeze out of the state.
 *
 * \sa esch_384_hash_init(), esch_384_hash_update()
 */
void esch_384_hash_squeeze
    (esch_384_hash_state_t *state, unsigned char *out, size_t outlen);

#ifdef __cplusplus
}
#endif

#endif