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/*
* ElGamal
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_ELGAMAL_H__
#define BOTAN_ELGAMAL_H__
#include <botan/dl_algo.h>
namespace Botan {
/**
* ElGamal Public Key
*/
class BOTAN_DLL ElGamal_PublicKey : public virtual DL_Scheme_PublicKey
{
public:
std::string algo_name() const override { return "ElGamal"; }
DL_Group::Format group_format() const override { return DL_Group::ANSI_X9_42; }
size_t max_input_bits() const override { return (group_p().bits() - 1); }
/**
* Load a public key.
* @param alg_id the X.509 algorithm identifier
* @param key_bits X.509 subject public key info structure
*/
ElGamal_PublicKey(const AlgorithmIdentifier& alg_id,
const secure_vector<byte>& key_bits) :
DL_Scheme_PublicKey(alg_id, key_bits, DL_Group::ANSI_X9_42)
{}
/**
* Create a public key.
* @param group the underlying DL group
* @param y the public value y = g^x mod p
*/
ElGamal_PublicKey(const DL_Group& group, const BigInt& y);
std::unique_ptr<PK_Ops::Encryption>
create_encryption_op(RandomNumberGenerator& rng,
const std::string& params,
const std::string& provider) const override;
protected:
ElGamal_PublicKey() {}
};
/**
* ElGamal Private Key
*/
class BOTAN_DLL ElGamal_PrivateKey : public ElGamal_PublicKey,
public virtual DL_Scheme_PrivateKey
{
public:
bool check_key(RandomNumberGenerator& rng, bool) const override;
/**
* Load a private key.
* @param alg_id the X.509 algorithm identifier
* @param key_bits PKCS #8 structure
* @paran rng the RNG to use
*/
ElGamal_PrivateKey(const AlgorithmIdentifier& alg_id,
const secure_vector<byte>& key_bits,
RandomNumberGenerator& rng);
/**
* Create a private key.
* @param rng random number generator to use
* @param grp the group to be used in the key
* @param priv_key the key's secret value (or if zero, generate a new key)
*/
ElGamal_PrivateKey(RandomNumberGenerator& rng,
const DL_Group& group,
const BigInt& priv_key = 0);
std::unique_ptr<PK_Ops::Decryption>
create_decryption_op(RandomNumberGenerator& rng,
const std::string& params,
const std::string& provider) const override;
};
}
#endif
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