text: // 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"
  
  #ifdef CRYPTOPP_IS_DLL
  #include "sha.h"
  #endif
  
  NAMESPACE_BEGIN(CryptoPP)
  
  //! \class PKCS_EncryptionPaddingScheme
  //! \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;
  };
  
  //! \class PKCS_DigestDecoration
  //! \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
  class SHA1;
  class SHA224;
  class SHA256;
  class SHA384;
  class SHA512;
  class Tiger;
  class RIPEMD160;
  namespace Weak1 {
  class MD2;
  class MD5;
  }
  // end of list
  
  #ifdef 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>;
  #endif
  
  //! \class PKCS1v15_SignatureMessageEncodingMethod
  //! \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);
  			}
  		};
  	};
  };
  
  //! PKCS #1 version 1.5, for use with RSAES and RSASS
  /*! Only the following hash functions are supported by this signature standard:
  	\dontinclude pkcspad.h
  	\skip can be instantiated
  	\until end of list
  */
  struct PKCS1v15 : public SignatureStandard, public EncryptionStandard
  {
  	typedef PKCS_EncryptionPaddingScheme EncryptionMessageEncodingMethod;
  	typedef PKCS1v15_SignatureMessageEncodingMethod SignatureMessageEncodingMethod;
  };
  
  NAMESPACE_END
  
  #endif
  