diff options
Diffstat (limited to 'CryptoPP/elgamal.h')
-rw-r--r-- | CryptoPP/elgamal.h | 121 |
1 files changed, 0 insertions, 121 deletions
diff --git a/CryptoPP/elgamal.h b/CryptoPP/elgamal.h deleted file mode 100644 index 9afc30eee..000000000 --- a/CryptoPP/elgamal.h +++ /dev/null @@ -1,121 +0,0 @@ -#ifndef CRYPTOPP_ELGAMAL_H -#define CRYPTOPP_ELGAMAL_H - -#include "modexppc.h" -#include "dsa.h" - -NAMESPACE_BEGIN(CryptoPP) - -class CRYPTOPP_NO_VTABLE ElGamalBase : public DL_KeyAgreementAlgorithm_DH<Integer, NoCofactorMultiplication>, - public DL_KeyDerivationAlgorithm<Integer>, - public DL_SymmetricEncryptionAlgorithm -{ -public: - void Derive(const DL_GroupParameters<Integer> &groupParams, byte *derivedKey, size_t derivedLength, const Integer &agreedElement, const Integer &ephemeralPublicKey, const NameValuePairs &derivationParams) const - { - agreedElement.Encode(derivedKey, derivedLength); - } - - size_t GetSymmetricKeyLength(size_t plainTextLength) const - { - return GetGroupParameters().GetModulus().ByteCount(); - } - - size_t GetSymmetricCiphertextLength(size_t plainTextLength) const - { - unsigned int len = GetGroupParameters().GetModulus().ByteCount(); - if (plainTextLength <= GetMaxSymmetricPlaintextLength(len)) - return len; - else - return 0; - } - - size_t GetMaxSymmetricPlaintextLength(size_t cipherTextLength) const - { - unsigned int len = GetGroupParameters().GetModulus().ByteCount(); - if (cipherTextLength == len) - return STDMIN(255U, len-3); - else - return 0; - } - - void SymmetricEncrypt(RandomNumberGenerator &rng, const byte *key, const byte *plainText, size_t plainTextLength, byte *cipherText, const NameValuePairs ¶meters) const - { - const Integer &p = GetGroupParameters().GetModulus(); - unsigned int modulusLen = p.ByteCount(); - - SecByteBlock block(modulusLen-1); - rng.GenerateBlock(block, modulusLen-2-plainTextLength); - memcpy(block+modulusLen-2-plainTextLength, plainText, plainTextLength); - block[modulusLen-2] = (byte)plainTextLength; - - a_times_b_mod_c(Integer(key, modulusLen), Integer(block, modulusLen-1), p).Encode(cipherText, modulusLen); - } - - DecodingResult SymmetricDecrypt(const byte *key, const byte *cipherText, size_t cipherTextLength, byte *plainText, const NameValuePairs ¶meters) const - { - const Integer &p = GetGroupParameters().GetModulus(); - unsigned int modulusLen = p.ByteCount(); - - if (cipherTextLength != modulusLen) - return DecodingResult(); - - Integer m = a_times_b_mod_c(Integer(cipherText, modulusLen), Integer(key, modulusLen).InverseMod(p), p); - - m.Encode(plainText, 1); - unsigned int plainTextLength = plainText[0]; - if (plainTextLength > GetMaxSymmetricPlaintextLength(modulusLen)) - return DecodingResult(); - m >>= 8; - m.Encode(plainText, plainTextLength); - return DecodingResult(plainTextLength); - } - - virtual const DL_GroupParameters_GFP & GetGroupParameters() const =0; -}; - -template <class BASE, class SCHEME_OPTIONS, class KEY> -class ElGamalObjectImpl : public DL_ObjectImplBase<BASE, SCHEME_OPTIONS, KEY>, public ElGamalBase -{ -public: - size_t FixedMaxPlaintextLength() const {return this->MaxPlaintextLength(FixedCiphertextLength());} - size_t FixedCiphertextLength() const {return this->CiphertextLength(0);} - - const DL_GroupParameters_GFP & GetGroupParameters() const {return this->GetKey().GetGroupParameters();} - - DecodingResult FixedLengthDecrypt(RandomNumberGenerator &rng, const byte *cipherText, byte *plainText) const - {return Decrypt(rng, cipherText, FixedCiphertextLength(), plainText);} - -protected: - const DL_KeyAgreementAlgorithm<Integer> & GetKeyAgreementAlgorithm() const {return *this;} - const DL_KeyDerivationAlgorithm<Integer> & GetKeyDerivationAlgorithm() const {return *this;} - const DL_SymmetricEncryptionAlgorithm & GetSymmetricEncryptionAlgorithm() const {return *this;} -}; - -struct ElGamalKeys -{ - typedef DL_CryptoKeys_GFP::GroupParameters GroupParameters; - typedef DL_PrivateKey_GFP_OldFormat<DL_CryptoKeys_GFP::PrivateKey> PrivateKey; - typedef DL_PublicKey_GFP_OldFormat<DL_CryptoKeys_GFP::PublicKey> PublicKey; -}; - -//! ElGamal encryption scheme with non-standard padding -struct ElGamal -{ - typedef DL_CryptoSchemeOptions<ElGamal, ElGamalKeys, int, int, int> SchemeOptions; - - static const char * StaticAlgorithmName() {return "ElgamalEnc/Crypto++Padding";} - - typedef SchemeOptions::GroupParameters GroupParameters; - //! implements PK_Encryptor interface - typedef PK_FinalTemplate<ElGamalObjectImpl<DL_EncryptorBase<Integer>, SchemeOptions, SchemeOptions::PublicKey> > Encryptor; - //! implements PK_Decryptor interface - typedef PK_FinalTemplate<ElGamalObjectImpl<DL_DecryptorBase<Integer>, SchemeOptions, SchemeOptions::PrivateKey> > Decryptor; -}; - -typedef ElGamal::Encryptor ElGamalEncryptor; -typedef ElGamal::Decryptor ElGamalDecryptor; - -NAMESPACE_END - -#endif |