/*
 * Compilation Copyright (c) 1995-2019 by Wei Dai.  All rights reserved.
 *	This copyright applies only to this software distribution package
 *	as a compilation, and does not imply a copyright on any particular
 *	file in the package.
 * 
 *	Boost Software License - Version 1.0 - August 17th, 2003
 *
 *	Permission is hereby granted, free of charge, to any person or organization
 *	obtaining a copy of the software and accompanying documentation covered by
 *	this license (the "Software") to use, reproduce, display, distribute,
 *	execute, and transmit the Software, and to prepare derivative works of the
 *	Software, and to permit third-parties to whom the Software is furnished to
 *	do so, all subject to the following:
 * 
 *	The copyright notices in the Software and this entire statement, including
 *	the above license grant, this restriction and the following disclaimer,
 *	must be included in all copies of the Software, in whole or in part, and
 *	all derivative works of the Software, unless such copies or derivative
 *	works are solely in the form of machine-executable object code generated by
 *	a source language processor.
 *
 *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *	FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
 *	SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
 *	FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
 *	ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 *	DEALINGS IN THE SOFTWARE.
 */

// pkcspad.h - originally written and placed in the public domain by Wei Dai

/// \file pkcspad.h
/// \brief Classes for PKCS padding schemes
/// \details PKCS #1 v1.5, v2.0 and P1363a allow MD2, MD5, SHA1, SHA224, SHA256, SHA384,
///   SHA512, Tiger and RipeMd-160 to be instantiated.

#ifndef CRYPTOPP_PKCSPAD_H
#define CRYPTOPP_PKCSPAD_H

#include "cryptlib.h"
#include "pubkey.h"
#include "hashfwd.h"

#ifdef CRYPTOPP_IS_DLL
#include "sha.h"
#endif

NAMESPACE_BEGIN(CryptoPP)

/// \brief PKCS #1 v1.5 Encryption Padding Scheme
/// \sa <a href="http://www.weidai.com/scan-mirror/ca.html#cem_PKCS1-1.5">EME-PKCS1-v1_5</a>
class PKCS_EncryptionPaddingScheme : public PK_EncryptionMessageEncodingMethod
{
public:
	CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "EME-PKCS1-v1_5";}

	size_t MaxUnpaddedLength(size_t paddedLength) const;
	void Pad(RandomNumberGenerator &rng, const byte *raw, size_t inputLength, byte *padded, size_t paddedLength, const NameValuePairs &parameters) const;
	DecodingResult Unpad(const byte *padded, size_t paddedLength, byte *raw, const NameValuePairs &parameters) const;
};

/// \brief PKCS #1 decoration data structure
template <class H> class PKCS_DigestDecoration
{
public:
	static const byte decoration[];
	static const unsigned int length;
};

// PKCS_DigestDecoration can be instantiated with the following
// classes as specified in PKCS #1 v2.0 and P1363a
// SHA1, SHA224, SHA256, SHA384, SHA512, Tiger, RIPEMD160, MD2, MD5

#if defined(CRYPTOPP_IS_DLL)
CRYPTOPP_DLL_TEMPLATE_CLASS PKCS_DigestDecoration<SHA1>;
CRYPTOPP_DLL_TEMPLATE_CLASS PKCS_DigestDecoration<SHA224>;
CRYPTOPP_DLL_TEMPLATE_CLASS PKCS_DigestDecoration<SHA256>;
CRYPTOPP_DLL_TEMPLATE_CLASS PKCS_DigestDecoration<SHA384>;
CRYPTOPP_DLL_TEMPLATE_CLASS PKCS_DigestDecoration<SHA512>;
// http://github.com/weidai11/cryptopp/issues/517
CRYPTOPP_DLL_TEMPLATE_CLASS PKCS_DigestDecoration<SHA3_256>;
CRYPTOPP_DLL_TEMPLATE_CLASS PKCS_DigestDecoration<SHA3_384>;
CRYPTOPP_DLL_TEMPLATE_CLASS PKCS_DigestDecoration<SHA3_512>;
#endif

// https://github.com/weidai11/cryptopp/issues/300 and
// https://github.com/weidai11/cryptopp/issues/533
#if defined(__clang__)
template<> const byte PKCS_DigestDecoration<SHA1>::decoration[];
template<> const unsigned int PKCS_DigestDecoration<SHA1>::length;
template<> const byte PKCS_DigestDecoration<SHA224>::decoration[];
template<> const unsigned int PKCS_DigestDecoration<SHA224>::length;
template<> const byte PKCS_DigestDecoration<SHA256>::decoration[];
template<> const unsigned int PKCS_DigestDecoration<SHA256>::length;
template<> const byte PKCS_DigestDecoration<SHA384>::decoration[];
template<> const unsigned int PKCS_DigestDecoration<SHA384>::length;
template<> const byte PKCS_DigestDecoration<SHA512>::decoration[];
template<> const unsigned int PKCS_DigestDecoration<SHA512>::length;

// http://github.com/weidai11/cryptopp/issues/517
template<> const byte PKCS_DigestDecoration<SHA3_256>::decoration[];
template<> const unsigned int PKCS_DigestDecoration<SHA3_256>::length;
template<> const byte PKCS_DigestDecoration<SHA3_384>::decoration[];
template<> const unsigned int PKCS_DigestDecoration<SHA3_384>::length;
template<> const byte PKCS_DigestDecoration<SHA3_512>::decoration[];
template<> const unsigned int PKCS_DigestDecoration<SHA3_512>::length;

template<> const byte PKCS_DigestDecoration<Weak1::MD2>::decoration[];
template<> const unsigned int PKCS_DigestDecoration<Weak1::MD2>::length;
template<> const byte PKCS_DigestDecoration<Weak1::MD5>::decoration[];
template<> const unsigned int PKCS_DigestDecoration<Weak1::MD5>::length;
#endif

/// \brief PKCS #1 v1.5 Signature Encoding Scheme
/// \sa <a href="http://www.weidai.com/scan-mirror/sig.html#sem_PKCS1-1.5">EMSA-PKCS1-v1_5</a>
class CRYPTOPP_DLL PKCS1v15_SignatureMessageEncodingMethod : public PK_DeterministicSignatureMessageEncodingMethod
{
public:
	CRYPTOPP_STATIC_CONSTEXPR const char* CRYPTOPP_API StaticAlgorithmName() {return "EMSA-PKCS1-v1_5";}

	size_t MinRepresentativeBitLength(size_t hashIdentifierSize, size_t digestSize) const
		{return 8 * (digestSize + hashIdentifierSize + 10);}

	void ComputeMessageRepresentative(RandomNumberGenerator &rng,
		const byte *recoverableMessage, size_t recoverableMessageLength,
		HashTransformation &hash, HashIdentifier hashIdentifier, bool messageEmpty,
		byte *representative, size_t representativeBitLength) const;

	struct HashIdentifierLookup
	{
		template <class H> struct HashIdentifierLookup2
		{
			static HashIdentifier Lookup()
			{
				return HashIdentifier(PKCS_DigestDecoration<H>::decoration, PKCS_DigestDecoration<H>::length);
			}
		};
	};
};

/// \brief PKCS #1 version 1.5, for use with RSAES and RSASS
/// \dontinclude pkcspad.h

struct PKCS1v15 : public SignatureStandard, public EncryptionStandard
{
	typedef PKCS_EncryptionPaddingScheme EncryptionMessageEncodingMethod;
	typedef PKCS1v15_SignatureMessageEncodingMethod SignatureMessageEncodingMethod;
};

NAMESPACE_END

#endif
