// 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 <vector>
#include "build/build_config.h"
#include "base/basictypes.h"
#include "crypto/crypto_export.h"
#if defined(USE_OPENSSL)
typedef struct env_md_st EVP_MD;
typedef struct evp_pkey_ctx_st EVP_PKEY_CTX;
#else
typedef struct HASHContextStr HASHContext;
typedef struct SECKEYPublicKeyStr SECKEYPublicKey;
typedef struct VFYContextStr VFYContext;
#endif
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,
};
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 algorithm is specified as a DER encoded ASN.1
// AlgorithmIdentifier structure:
// AlgorithmIdentifier ::= SEQUENCE {
// algorithm OBJECT IDENTIFIER,
// parameters ANY DEFINED BY algorithm OPTIONAL }
//
// The signature is encoded according to the signature algorithm, but it
// must not be further encoded in an ASN.1 BIT STRING.
// Note: An RSA signature is actually a big integer. It must be in
// big-endian byte order.
//
// 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(const uint8* signature_algorithm,
int signature_algorithm_len,
const uint8* signature,
int signature_len,
const uint8* public_key_info,
int 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,
int salt_len,
const uint8* signature,
int signature_len,
const uint8* public_key_info,
int public_key_info_len);
// Feeds a piece of the data to the signature verifier.
void VerifyUpdate(const uint8* data_part, int 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();
// Note: we can provide a one-shot interface if there is interest:
// bool Verify(const uint8* data,
// int data_len,
// const uint8* signature_algorithm,
// int signature_algorithm_len,
// const uint8* signature,
// int signature_len,
// const uint8* public_key_info,
// int public_key_info_len);
private:
#if defined(USE_OPENSSL)
bool CommonInit(const EVP_MD* digest,
const uint8* signature,
int signature_len,
const uint8* public_key_info,
int public_key_info_len,
EVP_PKEY_CTX** pkey_ctx);
#else
static SECKEYPublicKey* DecodePublicKeyInfo(const uint8* public_key_info,
int public_key_info_len);
#endif
void Reset();
std::vector<uint8> signature_;
#if defined(USE_OPENSSL)
struct VerifyContext;
VerifyContext* verify_context_;
#else
// Used for all signature types except RSA-PSS.
VFYContext* vfy_context_;
// Used for RSA-PSS signatures.
HashAlgorithm hash_alg_;
HashAlgorithm mask_hash_alg_;
unsigned int salt_len_;
SECKEYPublicKey* public_key_;
HASHContext* hash_context_;
#endif
};
} // namespace crypto
#endif // CRYPTO_SIGNATURE_VERIFIER_H_