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/*
* DL Scheme
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/dl_algo.h>
#include <botan/numthry.h>
#include <botan/workfactor.h>
#include <botan/der_enc.h>
#include <botan/ber_dec.h>
namespace Botan {
size_t DL_Scheme_PublicKey::key_length() const
{
return m_group.get_p().bits();
}
size_t DL_Scheme_PublicKey::estimated_strength() const
{
return dl_work_factor(key_length());
}
AlgorithmIdentifier DL_Scheme_PublicKey::algorithm_identifier() const
{
return AlgorithmIdentifier(get_oid(),
m_group.DER_encode(group_format()));
}
std::vector<byte> DL_Scheme_PublicKey::public_key_bits() const
{
return DER_Encoder().encode(m_y).get_contents_unlocked();
}
DL_Scheme_PublicKey::DL_Scheme_PublicKey(const AlgorithmIdentifier& alg_id,
const std::vector<byte>& key_bits,
DL_Group::Format format)
{
m_group.BER_decode(alg_id.parameters, format);
BER_Decoder(key_bits).decode(m_y);
}
secure_vector<byte> DL_Scheme_PrivateKey::private_key_bits() const
{
return DER_Encoder().encode(m_x).get_contents();
}
DL_Scheme_PrivateKey::DL_Scheme_PrivateKey(const AlgorithmIdentifier& alg_id,
const secure_vector<byte>& key_bits,
DL_Group::Format format)
{
m_group.BER_decode(alg_id.parameters, format);
BER_Decoder(key_bits).decode(m_x);
}
/*
* Check Public DL Parameters
*/
bool DL_Scheme_PublicKey::check_key(RandomNumberGenerator& rng,
bool strong) const
{
if(m_y < 2 || m_y >= group_p())
return false;
if(!m_group.verify_group(rng, strong))
return false;
if(power_mod(m_y,group_q(),group_p()) != 1)
return false;
return true;
}
/*
* Check DL Scheme Private Parameters
*/
bool DL_Scheme_PrivateKey::check_key(RandomNumberGenerator& rng,
bool strong) const
{
const BigInt& p = group_p();
const BigInt& g = group_g();
if(m_y < 2 || m_y >= p || m_x < 2 || m_x >= p)
return false;
if(!m_group.verify_group(rng, strong))
return false;
if(!strong)
return true;
if(m_y != power_mod(g, m_x, p))
return false;
return true;
}
}
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