c_api.cpp File Reference

C core implementation for Purify key validation, generation, derivation, and evaluation. More...

#include "purify.h"
#include <algorithm>
#include <array>
#include <cstdint>
#include <span>
#include <string_view>
#include "purify/curve.hpp"
#include "purify/error.hpp"
#include "purify/secret.hpp"
#include "core.h"
#include "error_bridge.hpp"

Go to the source code of this file.

Namespaces
namespace	purify
namespace	purify::capi_detail

Functions
bool	purify::capi_detail::ranges_overlap (const void *lhs, std::size_t lhs_size, const void *rhs, std::size_t rhs_size) noexcept
Bytes	purify::capi_detail::copy_bytes (const unsigned char *data, std::size_t size)
void	purify::capi_detail::clear_generated_key (purify_generated_key *out) noexcept
void	purify::capi_detail::clear_bip340_key (purify_bip340_key *out) noexcept
const UInt256 &	purify::capi_detail::secp256k1_order ()
const UInt256 &	purify::capi_detail::secp256k1_order_minus_one ()
Bytes	purify::capi_detail::tagged_message (std::string_view prefix, const Bytes &message)
Result< UInt512 >	purify::capi_detail::parse_secret_key (const unsigned char *secret_key)
Result< UInt512 >	purify::capi_detail::parse_public_key (const unsigned char *public_key)
void	purify::capi_detail::write_uint512 (const UInt512 &value, unsigned char *out)
void	purify::capi_detail::write_field_element (const FieldElement &value, unsigned char *out)
Result< UInt512 >	purify::capi_detail::derive_public_key_from_secret (const UInt512 &secret)
purify_error_code	purify_generate_key (purify_generated_key *out)
	Generates one random Purify keypair.
purify_error_code	purify_generate_key_from_seed (purify_generated_key *out, const unsigned char *seed, size_t seed_len)
	Deterministically derives one Purify keypair from seed material.
purify_error_code	purify_derive_public_key (unsigned char out_public_key[PURIFY_PUBLIC_KEY_BYTES], const unsigned char secret_key[PURIFY_SECRET_KEY_BYTES])
	Derives the packed public key corresponding to one packed Purify secret.
purify_error_code	purify_derive_bip340_key (purify_bip340_key *out, const unsigned char secret_key[PURIFY_SECRET_KEY_BYTES], purify_secp_context *secp_context)
	Derives one canonical BIP340 keypair from one packed Purify secret.
purify_error_code	purify_eval (unsigned char out_field_element[PURIFY_FIELD_ELEMENT_BYTES], const unsigned char secret_key[PURIFY_SECRET_KEY_BYTES], const unsigned char *message, size_t message_len)
	Evaluates the Purify PRF for one packed secret and message.

Function Documentation

purify_derive_bip340_key()

purify_error_code purify_derive_bip340_key	(	purify_bip340_key *	out,
		const unsigned char	secret_key[PURIFY_SECRET_KEY_BYTES],
		purify_secp_context *	secp_context
	)

Parameters

out	Output BIP340 keypair.
secret_key	Input 64-byte packed Purify secret.
secp_context	Caller-owned reusable context created by purify_secp_context_create. Aliasing: supported when out overlaps secret_key.

Returns

PURIFY_ERROR_OK on success.

Definition at line 217 of file c_api.cpp.

References purify::bytes_from_ascii(), purify::capi_detail::clear_bip340_key(), purify::Expected< T, E >::error(), purify::Expected< T, E >::has_value(), purify::capi_detail::parse_secret_key(), purify_bip340_key_from_seckey(), PURIFY_ERROR_BACKEND_REJECTED_INPUT, PURIFY_ERROR_INTERNAL_MISMATCH, PURIFY_ERROR_MISSING_VALUE, PURIFY_ERROR_OK, scalar, purify::capi_detail::secp256k1_order_minus_one(), purify_bip340_key::secret_key, purify::detail::secure_clear_bytes(), purify::core_api_detail::to_core_error_code(), and purify_bip340_key::xonly_public_key.

Referenced by purify::derive_bip340_key().

purify_derive_public_key()

purify_error_code purify_derive_public_key	(	unsigned char	out_public_key[PURIFY_PUBLIC_KEY_BYTES],
		const unsigned char	secret_key[PURIFY_SECRET_KEY_BYTES]
	)

Parameters

out_public_key	Output 64-byte packed Purify public key.
secret_key	Input 64-byte packed Purify secret. Aliasing: supported when out_public_key overlaps secret_key.

Returns

PURIFY_ERROR_OK on success.

Definition at line 196 of file c_api.cpp.

References purify::capi_detail::derive_public_key_from_secret(), purify::Expected< T, E >::error(), purify::Expected< T, E >::has_value(), purify::capi_detail::parse_secret_key(), PURIFY_ERROR_MISSING_VALUE, PURIFY_ERROR_OK, PURIFY_PUBLIC_KEY_BYTES, purify::core_api_detail::to_core_error_code(), and purify::capi_detail::write_uint512().

Referenced by purify::derive_key().

purify_eval()

purify_error_code purify_eval	(	unsigned char	out_field_element[PURIFY_FIELD_ELEMENT_BYTES],
		const unsigned char	secret_key[PURIFY_SECRET_KEY_BYTES],
		const unsigned char *	message,
		size_t	message_len
	)

Parameters

out_field_element	Output 32-byte big-endian field element.
secret_key	Input 64-byte packed Purify secret.
message	Message bytes. May be NULL only when message_len == 0.
message_len	Message length in bytes. Aliasing: supported when out_field_element overlaps secret_key and/or message.

Returns

PURIFY_ERROR_OK on success.

Definition at line 263 of file c_api.cpp.

References purify::combine(), purify::capi_detail::copy_bytes(), purify::curve1(), purify::curve2(), purify::Expected< T, E >::error(), purify::Expected< T, E >::has_value(), purify::hash_to_curve(), purify::EllipticCurve::mul_secret_affine(), purify::capi_detail::parse_secret_key(), PURIFY_ERROR_MISSING_VALUE, PURIFY_ERROR_OK, PURIFY_FIELD_ELEMENT_BYTES, purify::capi_detail::tagged_message(), purify::core_api_detail::to_core_error_code(), purify::unpack_secret(), and purify::capi_detail::write_field_element().

Referenced by purify::eval().

purify_generate_key()

purify_error_code purify_generate_key

(

purify_generated_key *

out

)

Parameters

out	Output bundle.

Returns

PURIFY_ERROR_OK on success.

Definition at line 134 of file c_api.cpp.

References purify::capi_detail::clear_generated_key(), purify::capi_detail::derive_public_key_from_secret(), purify::Expected< T, E >::error(), purify::Expected< T, E >::has_value(), purify::capi_detail::parse_secret_key(), purify_generated_key::public_key, purify_core_sample_secret_key(), PURIFY_ERROR_MISSING_VALUE, PURIFY_ERROR_OK, purify_generated_key::secret_key, purify::core_api_detail::to_core_error_code(), and purify::capi_detail::write_uint512().

Referenced by purify::generate_key().

purify_generate_key_from_seed()

purify_error_code purify_generate_key_from_seed	(	purify_generated_key *	out,
		const unsigned char *	seed,
		size_t	seed_len
	)

Parameters

out	Output bundle.
seed	Seed bytes. May be NULL only when seed_len == 0.
seed_len	Seed length in bytes. Values shorter than 16 bytes are rejected. Aliasing: supported when seed points anywhere inside out.

Returns

PURIFY_ERROR_OK on success.

Definition at line 161 of file c_api.cpp.

References purify::capi_detail::clear_generated_key(), purify::capi_detail::copy_bytes(), purify::capi_detail::derive_public_key_from_secret(), purify::Expected< T, E >::error(), purify::Expected< T, E >::has_value(), purify::capi_detail::parse_secret_key(), purify_generated_key::public_key, purify_core_seed_secret_key(), PURIFY_ERROR_MISSING_VALUE, PURIFY_ERROR_OK, purify::capi_detail::ranges_overlap(), purify_generated_key::secret_key, purify::core_api_detail::to_core_error_code(), and purify::capi_detail::write_uint512().

Referenced by purify::generate_key().