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externals/cryptopp/pssr.h

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+// pssr.h - originally written and placed in the public domain by Wei Dai
+
+/// \file pssr.h
+/// \brief Classes for probabilistic signature schemes
+/// \since Crypto++ 2.1
+
+#ifndef CRYPTOPP_PSSR_H
+#define CRYPTOPP_PSSR_H
+
+#include "cryptlib.h"
+#include "pubkey.h"
+#include "emsa2.h"
+
+#ifdef CRYPTOPP_IS_DLL
+#include "sha.h"
+#endif
+
+NAMESPACE_BEGIN(CryptoPP)
+
+/// \brief PSSR Message Encoding Method interface
+/// \since Crypto++ 2.1
+class CRYPTOPP_DLL PSSR_MEM_Base : public PK_RecoverableSignatureMessageEncodingMethod
+{
+public:
+	virtual ~PSSR_MEM_Base() {}
+
+protected:
+	virtual bool AllowRecovery() const =0;
+	virtual size_t SaltLen(size_t hashLen) const =0;
+	virtual size_t MinPadLen(size_t hashLen) const =0;
+	virtual const MaskGeneratingFunction & GetMGF() const =0;
+
+private:
+	size_t MinRepresentativeBitLength(size_t hashIdentifierLength, size_t digestLength) const;
+	size_t MaxRecoverableLength(size_t representativeBitLength, size_t hashIdentifierLength, size_t digestLength) const;
+	bool IsProbabilistic() const;
+	bool AllowNonrecoverablePart() const;
+	bool RecoverablePartFirst() const;
+	void ComputeMessageRepresentative(RandomNumberGenerator &rng,
+		const byte *recoverableMessage, size_t recoverableMessageLength,
+		HashTransformation &hash, HashIdentifier hashIdentifier, bool messageEmpty,
+		byte *representative, size_t representativeBitLength) const;
+	DecodingResult RecoverMessageFromRepresentative(
+		HashTransformation &hash, HashIdentifier hashIdentifier, bool messageEmpty,
+		byte *representative, size_t representativeBitLength,
+		byte *recoverableMessage) const;
+};
+
+/// \brief PSSR Message Encoding Method with Hash Identifier
+/// \tparam USE_HASH_ID flag indicating whether the HashId is used
+/// \since Crypto++ 2.1
+template <bool USE_HASH_ID> class PSSR_MEM_BaseWithHashId;
+
+/// \brief PSSR Message Encoding Method with Hash Identifier
+/// \details If USE_HASH_ID is true, then EMSA2HashIdLookup<PSSR_MEM_Base> is used for the base class
+template<> class PSSR_MEM_BaseWithHashId<true> : public EMSA2HashIdLookup<PSSR_MEM_Base> {};
+
+/// \brief PSSR Message Encoding Method without Hash Identifier
+/// \details If USE_HASH_ID is false, then PSSR_MEM_Base is used for the base class
+/// \since Crypto++ 2.1
+template<> class PSSR_MEM_BaseWithHashId<false> : public PSSR_MEM_Base {};
+
+/// \brief PSSR Message Encoding Method
+/// \tparam ALLOW_RECOVERY flag indicating whether the scheme provides message recovery
+/// \tparam MGF mask generation function
+/// \tparam SALT_LEN length of the salt
+/// \tparam MIN_PAD_LEN minimum length of the pad
+/// \tparam USE_HASH_ID flag indicating whether the HashId is used
+/// \details If ALLOW_RECOVERY is true, the signature scheme provides message recovery. If
+///  ALLOW_RECOVERY is false, the signature scheme is appendix, and the message must be
+///  provided during verification.
+/// \since Crypto++ 2.1
+template <bool ALLOW_RECOVERY, class MGF=P1363_MGF1, int SALT_LEN=-1, int MIN_PAD_LEN=0, bool USE_HASH_ID=false>
+class PSSR_MEM : public PSSR_MEM_BaseWithHashId<USE_HASH_ID>
+{
+	virtual bool AllowRecovery() const {return ALLOW_RECOVERY;}
+	virtual size_t SaltLen(size_t hashLen) const {return SALT_LEN < 0 ? hashLen : SALT_LEN;}
+	virtual size_t MinPadLen(size_t hashLen) const {return MIN_PAD_LEN < 0 ? hashLen : MIN_PAD_LEN;}
+	virtual const MaskGeneratingFunction & GetMGF() const {static MGF mgf; return mgf;}
+
+public:
+	static std::string CRYPTOPP_API StaticAlgorithmName() {return std::string(ALLOW_RECOVERY ? "PSSR-" : "PSS-") + MGF::StaticAlgorithmName();}
+};
+
+/// \brief Probabilistic Signature Scheme with Recovery
+/// \details Signature Schemes with Recovery encode the message with the signature.
+/// \sa <a href="http://www.weidai.com/scan-mirror/sig.html#sem_PSSR-MGF1">PSSR-MGF1</a>
+/// \since Crypto++ 2.1
+struct PSSR : public SignatureStandard
+{
+	typedef PSSR_MEM<true> SignatureMessageEncodingMethod;
+};
+
+/// \brief Probabilistic Signature Scheme with Appendix
+/// \details Signature Schemes with Appendix require the message to be provided during verification.
+/// \sa <a href="http://www.weidai.com/scan-mirror/sig.html#sem_PSS-MGF1">PSS-MGF1</a>
+/// \since Crypto++ 2.1
+struct PSS : public SignatureStandard
+{
+	typedef PSSR_MEM<false> SignatureMessageEncodingMethod;
+};
+
+NAMESPACE_END
+
+#endif