salty.h

#ifndef salty_h
#define salty_h

/* Warning, this file is autogenerated by cbindgen. Don't modify this manually. */

#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

#define salty_FIELD_ELEMENT_LENGTH 32

#define salty_PUBLICKEY_SERIALIZED_LENGTH 32

#define salty_SECRETKEY_SEED_LENGTH 32

#define salty_SIGNATURE_SERIALIZED_LENGTH 64

#define salty_SHA512_LENGTH 64

/**
 * Size of an encoded Ed25519 signature in bytes.
 */
#define salty_Signature_BYTE_SIZE 64

/**
 * Extensible error type for all `salty` operations.
 *
 * This enum has a hidden member, to prevent exhaustively checking for errors.
 * It also has a member `NoError` with value zero, for use in the C API.
 */
typedef enum salty_Error {
  /**
   * Never occurs, simplifies C bindings
   */
  NoError = 0,
  /**
   * Bytes do not correspond to a canonical base field element
   */
  NonCanonicalFieldElement,
  /**
   * Public key bytes invalid
   */
  PublicKeyBytesInvalid,
  /**
   * Signature verification failed
   */
  SignatureInvalid,
  /**
   * Context for prehashed signatures too long
   */
  ContextTooLong,
  /**
   * Point is on other twist of curve
   */
  WrongTwist,
  _Extensible,
} salty_Error;

/**
 * Generates a public key from a secret seed. Use to verify signatures.
 */
void salty_public_key(const uint8_t (*seed)[salty_SECRETKEY_SEED_LENGTH],
                      uint8_t (*public_key)[salty_PUBLICKEY_SERIALIZED_LENGTH]);

/**
 * Signs the data, based on the keypair generated from the secret seed.
 */
void salty_sign(const uint8_t (*seed)[salty_SECRETKEY_SEED_LENGTH],
                const uint8_t *data_ptr,
                uintptr_t data_len,
                uint8_t (*signature)[salty_SIGNATURE_SERIALIZED_LENGTH]);

/**
 * Signs the data for a given context, based on the keypair generated
 * from the secret seed.
 */
enum salty_Error salty_sign_with_context(const uint8_t (*seed)[salty_SECRETKEY_SEED_LENGTH],
                                         const uint8_t *data_ptr,
                                         uintptr_t data_len,
                                         const uint8_t *context_ptr,
                                         uintptr_t context_len,
                                         uint8_t (*signature)[salty_SIGNATURE_SERIALIZED_LENGTH]);

/**
 * Signs the prehashed data, based on the keypair generated from the secret seed.
 * An optional context can also be passed (this is recommended).
 */
enum salty_Error salty_sign_prehashed(const uint8_t (*seed)[salty_SECRETKEY_SEED_LENGTH],
                                      const uint8_t (*prehashed_data)[salty_SHA512_LENGTH],
                                      const uint8_t *context_ptr,
                                      uintptr_t context_len,
                                      uint8_t (*signature)[salty_SIGNATURE_SERIALIZED_LENGTH]);

/**
 * Verify a presumed signature on the given data.
 */
enum salty_Error salty_verify(const uint8_t (*public_key)[salty_PUBLICKEY_SERIALIZED_LENGTH],
                              const uint8_t *data_ptr,
                              uintptr_t data_len,
                              const uint8_t (*signature)[salty_SIGNATURE_SERIALIZED_LENGTH]);

/**
 * Verify a presumed signature on the given data.
 */
enum salty_Error salty_verify_with_context(const uint8_t (*public_key)[salty_PUBLICKEY_SERIALIZED_LENGTH],
                                           const uint8_t *data_ptr,
                                           uintptr_t data_len,
                                           const uint8_t (*signature)[salty_SIGNATURE_SERIALIZED_LENGTH],
                                           const uint8_t *context_ptr,
                                           uintptr_t context_len);

/**
 * Verify a presumed signature on the given data.
 */
enum salty_Error salty_verify_prehashed(const uint8_t (*public_key)[salty_PUBLICKEY_SERIALIZED_LENGTH],
                                        const uint8_t (*prehashed_data)[salty_SHA512_LENGTH],
                                        const uint8_t (*signature)[salty_SIGNATURE_SERIALIZED_LENGTH],
                                        const uint8_t *context_ptr,
                                        uintptr_t context_len);

/**
 * Perform X25519 key agreement.
 */
void salty_agree(const uint8_t (*scalar)[salty_SECRETKEY_SEED_LENGTH],
                 const uint8_t (*input_u)[salty_FIELD_ELEMENT_LENGTH],
                 uint8_t (*output_u)[salty_FIELD_ELEMENT_LENGTH]);

#endif /* salty_h */