c-kzg-4844/min-src/c_kzg_4844.h

124 lines
4.7 KiB
C

/*
* Copyright 2021 Benjamin Edgington
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file c_kzg_4844.h
*
* Minimal interface required for EIP-4844.
*/
#ifndef C_KZG_4844_H
#define C_KZG_4844_H
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include "blst.h"
typedef blst_p1 g1_t; /**< Internal G1 group element type */
typedef blst_p2 g2_t; /**< Internal G2 group element type */
typedef blst_fr fr_t; /**< Internal Fr field element type */
typedef g1_t KZGCommitment;
typedef g1_t KZGProof;
typedef fr_t BLSFieldElement;
/**
* KZGCommitment and KZGProof can be recovered as 48 bytes
*/
void bytes_from_G1(uint8_t out[48], const g1_t*);
/**
* BLSFieldElements are communicated directly to/from clients,
* so we need to expose the functions for translating between this
* type and uint256. BLST represents uint256 as uint64[4].
*/
void BLSFieldElement_from_uint64s(BLSFieldElement *out, const uint64_t[4]);
void uint64s_from_BLSFieldElement(uint64_t out[4], const BLSFieldElement*);
/**
* The common return type for all routines in which something can go wrong.
*
* @warning In the case of @p C_KZG_OK or @p C_KZG_BADARGS, the caller can assume that all memory allocated by the
* called routines has been deallocated. However, in the case of @p C_KZG_ERROR or @p C_KZG_MALLOC being returned, these
* are unrecoverable and memory may have been leaked.
*/
typedef enum {
C_KZG_OK = 0, /**< Success! */
C_KZG_BADARGS, /**< The supplied data is invalid in some way */
C_KZG_ERROR, /**< Internal error - this should never occur and may indicate a bug in the library */
C_KZG_MALLOC, /**< Could not allocate memory */
} C_KZG_RET;
/**
* Stores the setup and parameters needed for performing FFTs.
*/
typedef struct {
uint64_t max_width; /**< The maximum size of FFT these settings support, a power of 2. */
fr_t *expanded_roots_of_unity; /**< Ascending powers of the root of unity, size `width + 1`. */
fr_t *reverse_roots_of_unity; /**< Descending powers of the root of unity, size `width + 1`. */
fr_t *roots_of_unity; /**< Powers of the root of unity in bit-reversal permutation, size `width`. */
} FFTSettings;
/**
* Stores the setup and parameters needed for computing KZG proofs.
*/
typedef struct {
const FFTSettings *fs; /**< The corresponding settings for performing FFTs */
g1_t *g1_values; /**< G1 group elements from the trusted setup, in Lagrange form bit-reversal permutation */
g2_t *g2_values; /**< G2 group elements from the trusted setup */
uint64_t length; /**< The number of elements in g1_values */
} KZGSettings;
/**
* Lagrange form polynomial, with values under the bit-reversal permutation
*/
typedef struct {
fr_t *values; /**< `values[i]` is value of the polynomial at `ω^brp(i)` */
uint64_t length; /**< One more than the polynomial's degree */
} PolynomialEvalForm;
C_KZG_RET alloc_polynomial(PolynomialEvalForm *out, uint64_t length);
void free_polynomial(PolynomialEvalForm *p);
/**
* Interface functions
*/
C_KZG_RET load_trusted_setup(KZGSettings *out, FILE *in);
void free_trusted_setup(KZGSettings *s);
void bytes_to_bls_field(BLSFieldElement *out, const uint8_t bytes[32]);
void vector_lincomb(BLSFieldElement out[], const BLSFieldElement* vectors[], const BLSFieldElement* scalars[], uint64_t num_vectors, uint64_t vector_len);
void g1_lincomb(KZGCommitment *out, const KZGCommitment points[], const BLSFieldElement scalars[], uint64_t num_points);
void blob_to_kzg_commitment(KZGCommitment *out, const BLSFieldElement blob[], const KZGSettings *s);
C_KZG_RET verify_kzg_proof(bool *out, const KZGCommitment *polynomial_kzg, const BLSFieldElement *z, const BLSFieldElement *y, const KZGProof *kzg_proof, const KZGSettings *s);
C_KZG_RET compute_kzg_proof(KZGProof *out, const PolynomialEvalForm *polynomial, const BLSFieldElement *z, const KZGSettings *s);
C_KZG_RET evaluate_polynomial_in_evaluation_form(BLSFieldElement *out, const PolynomialEvalForm *polynomial, const BLSFieldElement *z, const KZGSettings *s);
void compute_powers(BLSFieldElement out[], const BLSFieldElement *x, uint64_t n);
#endif // C_KZG_4844_H