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/*
* ECDH
* (C) 2007 Falko Strenzke, FlexSecure GmbH
* Manuel Hartl, FlexSecure GmbH
* (C) 2008-2010 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#ifndef BOTAN_ECDH_KEY_H__
#define BOTAN_ECDH_KEY_H__
#include <botan/ecc_key.h>
#include <botan/pk_ops.h>
namespace Botan {
/**
* This class represents ECDH Public Keys.
*/
class BOTAN_DLL ECDH_PublicKey : public virtual EC_PublicKey
{
public:
ECDH_PublicKey(const AlgorithmIdentifier& alg_id,
const MemoryRegion<byte>& key_bits) :
EC_PublicKey(alg_id, key_bits) {}
/**
* Construct a public key from a given public point.
* @param dom_par the domain parameters associated with this key
* @param public_point the public point defining this key
*/
ECDH_PublicKey(const EC_Domain_Params& dom_par,
const PointGFp& public_point) :
EC_PublicKey(dom_par, public_point) {}
/**
* Get this keys algorithm name.
* @result this keys algorithm name
*/
std::string algo_name() const { return "ECDH"; }
/**
* Get the maximum number of bits allowed to be fed to this key.
* This is the bitlength of the order of the base point.
* @result the maximum number of input bits
*/
u32bit max_input_bits() const { return domain().get_order().bits(); }
protected:
ECDH_PublicKey() {}
};
/**
* This class represents ECDH Private Keys.
*/
class BOTAN_DLL ECDH_PrivateKey : public ECDH_PublicKey,
public EC_PrivateKey,
public PK_Key_Agreement_Key
{
public:
ECDH_PrivateKey(const AlgorithmIdentifier& alg_id,
const MemoryRegion<byte>& key_bits) :
EC_PrivateKey(alg_id, key_bits) {}
/**
* Generate a new private key
* @param the domain parameters to used for this key
*/
ECDH_PrivateKey(RandomNumberGenerator& rng,
const EC_Domain_Params& domain) :
EC_PrivateKey(rng, domain) {}
MemoryVector<byte> public_value() const
{ return EC2OSP(public_point(), PointGFp::UNCOMPRESSED); }
private:
/**
* Derive a shared key with the other parties public key.
* @param key the other partys public key
* @param key_len the other partys public key
*/
SecureVector<byte> derive_key(const byte key[], u32bit key_len) const;
/**
* Derive a shared key with the other parties public key.
* @param other the other partys public key
*/
SecureVector<byte> derive_key(const ECDH_PublicKey& other) const;
/**
* Derive a shared key with the other parties public key.
* @param point the public point of the other parties key
*/
SecureVector<byte> derive_key(const PointGFp& point) const;
};
/**
* ECDH operation
*/
class BOTAN_DLL ECDH_KA_Operation : public PK_Ops::KA_Operation
{
public:
ECDH_KA_Operation(const ECDH_PrivateKey& key);
SecureVector<byte> agree(const byte w[], u32bit w_len) const;
private:
const CurveGFp& curve;
const BigInt& cofactor;
BigInt l_times_priv;
};
}
#endif
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