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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CRYPTO_SIGNATURE_VERIFIER_H_
#define CRYPTO_SIGNATURE_VERIFIER_H_
#include <stdint.h>
#include <memory>
#include <vector>
#include "build/build_config.h"
#include "crypto/crypto_export.h"
typedef struct env_md_st EVP_MD;
typedef struct evp_pkey_ctx_st EVP_PKEY_CTX;
namespace crypto {
// The SignatureVerifier class verifies a signature using a bare public key
// (as opposed to a certificate).
class CRYPTO_EXPORT SignatureVerifier {
public:
// The set of supported hash functions. Extend as required.
enum HashAlgorithm {
SHA1,
SHA256,
};
// The set of supported signature algorithms. Extend as required.
enum SignatureAlgorithm {
RSA_PKCS1_SHA1,
RSA_PKCS1_SHA256,
ECDSA_SHA256,
};
SignatureVerifier();
~SignatureVerifier();
// Streaming interface:
// Initiates a signature verification operation. This should be followed
// by one or more VerifyUpdate calls and a VerifyFinal call.
// NOTE: for RSA-PSS signatures, use VerifyInitRSAPSS instead.
//
// The signature is encoded according to the signature algorithm.
//
// The public key is specified as a DER encoded ASN.1 SubjectPublicKeyInfo
// structure, which contains not only the public key but also its type
// (algorithm):
// SubjectPublicKeyInfo ::= SEQUENCE {
// algorithm AlgorithmIdentifier,
// subjectPublicKey BIT STRING }
bool VerifyInit(SignatureAlgorithm signature_algorithm,
const uint8_t* signature,
size_t signature_len,
const uint8_t* public_key_info,
size_t public_key_info_len);
// Initiates a RSA-PSS signature verification operation. This should be
// followed by one or more VerifyUpdate calls and a VerifyFinal call.
//
// The RSA-PSS signature algorithm parameters are specified with the
// |hash_alg|, |mask_hash_alg|, and |salt_len| arguments.
//
// An RSA-PSS signature is a nonnegative integer encoded as a byte string
// (of the same length as the RSA modulus) in big-endian byte order. It
// must not be further encoded in an ASN.1 BIT STRING.
//
// The public key is specified as a DER encoded ASN.1 SubjectPublicKeyInfo
// structure, which contains not only the public key but also its type
// (algorithm):
// SubjectPublicKeyInfo ::= SEQUENCE {
// algorithm AlgorithmIdentifier,
// subjectPublicKey BIT STRING }
bool VerifyInitRSAPSS(HashAlgorithm hash_alg,
HashAlgorithm mask_hash_alg,
size_t salt_len,
const uint8_t* signature,
size_t signature_len,
const uint8_t* public_key_info,
size_t public_key_info_len);
// Feeds a piece of the data to the signature verifier.
void VerifyUpdate(const uint8_t* data_part, size_t data_part_len);
// Concludes a signature verification operation. Returns true if the
// signature is valid. Returns false if the signature is invalid or an
// error occurred.
bool VerifyFinal();
private:
bool CommonInit(int pkey_type,
const EVP_MD* digest,
const uint8_t* signature,
size_t signature_len,
const uint8_t* public_key_info,
size_t public_key_info_len,
EVP_PKEY_CTX** pkey_ctx);
void Reset();
std::vector<uint8_t> signature_;
struct VerifyContext;
std::unique_ptr<VerifyContext> verify_context_;
};
} // namespace crypto
#endif // CRYPTO_SIGNATURE_VERIFIER_H_