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/*
* ECDSA implemenation
* (C) 2007 Manuel Hartl, FlexSecure GmbH
* 2007 Falko Strenzke, FlexSecure GmbH
* 2008 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/ecdsa.h>
#include <botan/numthry.h>
#include <botan/der_enc.h>
#include <botan/ber_dec.h>
#include <botan/secmem.h>
#include <botan/point_gfp.h>
namespace Botan {
ECDSA_PrivateKey::ECDSA_PrivateKey(RandomNumberGenerator& rng,
const EC_Domain_Params& dom_pars)
{
mp_dom_pars = std::unique_ptr<EC_Domain_Params>(new EC_Domain_Params(dom_pars));
generate_private_key(rng);
try
{
mp_public_point->check_invariants();
}
catch(Illegal_Point& e)
{
throw Invalid_State("ECDSA key generation failed");
}
m_ecdsa_core = ECDSA_Core(*mp_dom_pars, m_private_value, *mp_public_point);
}
/*
* ECDSA_PublicKey
*/
void ECDSA_PublicKey::affirm_init() const // virtual
{
EC_PublicKey::affirm_init();
}
void ECDSA_PublicKey::set_domain_parameters(const EC_Domain_Params& dom_pars)
{
if(mp_dom_pars.get())
{
// they are already set, we must ensure that they are equal to the arg
if(dom_pars != *mp_dom_pars.get())
throw Invalid_Argument("EC_PublicKey::set_domain_parameters - cannot reset to a new value");
return;
}
if(m_enc_public_point.size() == 0)
throw Invalid_State("EC_PublicKey::set_domain_parameters(): encoded public point isn't set");
// now try to decode the public key ...
PointGFp tmp_pp(OS2ECP(m_enc_public_point, dom_pars.get_curve()));
try
{
tmp_pp.check_invariants();
}
catch(Illegal_Point e)
{
throw Invalid_State("EC_PublicKey::set_domain_parameters(): point does not lie on provided curve");
}
mp_dom_pars.reset(new EC_Domain_Params(dom_pars));
ECDSA_Core tmp_ecdsa_core(*mp_dom_pars, BigInt(0), tmp_pp);
mp_public_point.reset(new PointGFp(tmp_pp));
m_ecdsa_core = tmp_ecdsa_core;
}
void ECDSA_PublicKey::set_all_values(const ECDSA_PublicKey& other)
{
m_param_enc = other.m_param_enc;
m_ecdsa_core = other.m_ecdsa_core;
m_enc_public_point = other.m_enc_public_point;
if(other.mp_dom_pars.get())
mp_dom_pars.reset(new EC_Domain_Params(other.domain_parameters()));
if(other.mp_public_point.get())
mp_public_point.reset(new PointGFp(other.public_point()));
}
ECDSA_PublicKey::ECDSA_PublicKey(const ECDSA_PublicKey& other)
: Public_Key(),
EC_PublicKey(),
PK_Verifying_wo_MR_Key()
{
set_all_values(other);
}
const ECDSA_PublicKey& ECDSA_PublicKey::operator=(const ECDSA_PublicKey& rhs)
{
set_all_values(rhs);
return *this;
}
bool ECDSA_PublicKey::verify(const byte message[],
u32bit mess_len,
const byte signature[],
u32bit sig_len) const
{
affirm_init();
BigInt r, s;
BER_Decoder(signature, sig_len)
.start_cons(SEQUENCE)
.decode(r)
.decode(s)
.end_cons()
.verify_end();
u32bit enc_len = std::max(r.bytes(), s.bytes());
SecureVector<byte> sv_plain_sig;
sv_plain_sig.append(BigInt::encode_1363(r, enc_len));
sv_plain_sig.append(BigInt::encode_1363(s, enc_len));
return m_ecdsa_core.verify(sv_plain_sig, sv_plain_sig.size(),
message, mess_len);
}
ECDSA_PublicKey::ECDSA_PublicKey(const EC_Domain_Params& dom_par,
const PointGFp& public_point)
{
mp_dom_pars = std::unique_ptr<EC_Domain_Params>(new EC_Domain_Params(dom_par));
mp_public_point = std::unique_ptr<PointGFp>(new PointGFp(public_point));
m_param_enc = ENC_EXPLICIT;
m_ecdsa_core = ECDSA_Core(*mp_dom_pars, BigInt(0), *mp_public_point);
}
void ECDSA_PublicKey::X509_load_hook()
{
EC_PublicKey::X509_load_hook();
EC_PublicKey::affirm_init();
m_ecdsa_core = ECDSA_Core ( *mp_dom_pars, BigInt ( 0 ), *mp_public_point );
}
u32bit ECDSA_PublicKey::max_input_bits() const
{
if(!mp_dom_pars.get())
{
throw Invalid_State("ECDSA_PublicKey::max_input_bits(): domain parameters not set");
}
return mp_dom_pars->get_order().bits();
}
/*************************
* ECDSA_PrivateKey
*************************/
void ECDSA_PrivateKey::affirm_init() const // virtual
{
EC_PrivateKey::affirm_init();
}
void ECDSA_PrivateKey::PKCS8_load_hook(bool generated)
{
EC_PrivateKey::PKCS8_load_hook(generated);
EC_PrivateKey::affirm_init();
m_ecdsa_core = ECDSA_Core(*mp_dom_pars, m_private_value, *mp_public_point);
}
void ECDSA_PrivateKey::set_all_values(const ECDSA_PrivateKey& other)
{
m_private_value = other.m_private_value;
m_param_enc = other.m_param_enc;
m_ecdsa_core = other.m_ecdsa_core;
m_enc_public_point = other.m_enc_public_point;
if(other.mp_dom_pars.get())
mp_dom_pars.reset(new EC_Domain_Params(other.domain_parameters()));
if(other.mp_public_point.get())
mp_public_point.reset(new PointGFp(other.public_point()));
}
ECDSA_PrivateKey::ECDSA_PrivateKey(ECDSA_PrivateKey const& other)
: Public_Key(),
EC_PublicKey(),
Private_Key(),
ECDSA_PublicKey(),
EC_PrivateKey(),
PK_Signing_Key()
{
set_all_values(other);
}
const ECDSA_PrivateKey& ECDSA_PrivateKey::operator=(const ECDSA_PrivateKey& rhs)
{
set_all_values(rhs);
return *this;
}
SecureVector<byte> ECDSA_PrivateKey::sign(const byte message[],
u32bit mess_len,
RandomNumberGenerator& rng) const
{
affirm_init();
SecureVector<byte> sv_sig = m_ecdsa_core.sign(message, mess_len, rng);
if(sv_sig.size() % 2 != 0)
throw Invalid_Argument("Erroneous length of signature");
u32bit rs_len = sv_sig.size() / 2;
SecureVector<byte> sv_r, sv_s;
sv_r.set(sv_sig.begin(), rs_len);
sv_s.set(&sv_sig[rs_len], rs_len);
BigInt r = BigInt::decode(sv_r, sv_r.size());
BigInt s = BigInt::decode(sv_s, sv_s.size());
return DER_Encoder()
.start_cons(SEQUENCE)
.encode(r)
.encode(s)
.end_cons()
.get_contents();
}
}
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