text: /*
   * 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"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included
   * in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   */
  
  #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
  