peerplays-fc/src/crypto/elliptic_impl_pub.cpp

358 lines
12 KiB
C++

#include <fc/fwd_impl.hpp>
#include <boost/config.hpp>
#include "_elliptic_impl_pub.hpp"
/* used by mixed + openssl */
namespace fc { namespace ecc {
namespace detail {
public_key_impl::public_key_impl() BOOST_NOEXCEPT
{
_init_lib();
}
public_key_impl::public_key_impl( const public_key_impl& cpy ) BOOST_NOEXCEPT
{
_init_lib();
*this = cpy;
}
public_key_impl::public_key_impl( public_key_impl&& cpy ) BOOST_NOEXCEPT
{
_init_lib();
*this = cpy;
}
public_key_impl::~public_key_impl() BOOST_NOEXCEPT
{
free_key();
}
public_key_impl& public_key_impl::operator=( const public_key_impl& pk ) BOOST_NOEXCEPT
{
if (pk._key == nullptr)
{
free_key();
} else if ( _key == nullptr ) {
_key = EC_KEY_dup( pk._key );
} else {
EC_KEY_copy( _key, pk._key );
}
return *this;
}
public_key_impl& public_key_impl::operator=( public_key_impl&& pk ) BOOST_NOEXCEPT
{
if ( this != &pk ) {
free_key();
_key = pk._key;
pk._key = nullptr;
}
return *this;
}
void public_key_impl::free_key() BOOST_NOEXCEPT
{
if( _key != nullptr )
{
EC_KEY_free(_key);
_key = nullptr;
}
}
// Perform ECDSA key recovery (see SEC1 4.1.6) for curves over (mod p)-fields
// recid selects which key is recovered
// if check is non-zero, additional checks are performed
int public_key_impl::ECDSA_SIG_recover_key_GFp(EC_KEY *eckey, ECDSA_SIG *ecsig,
const unsigned char *msg,
int msglen, int recid, int check)
{
if (!eckey) FC_THROW_EXCEPTION( exception, "null key" );
int ret = 0;
BN_CTX *ctx = NULL;
BIGNUM *x = NULL;
BIGNUM *e = NULL;
BIGNUM *order = NULL;
BIGNUM *sor = NULL;
BIGNUM *eor = NULL;
BIGNUM *field = NULL;
EC_POINT *R = NULL;
EC_POINT *O = NULL;
EC_POINT *Q = NULL;
BIGNUM *rr = NULL;
BIGNUM *zero = NULL;
int n = 0;
int i = recid / 2;
const EC_GROUP *group = EC_KEY_get0_group(eckey);
if ((ctx = BN_CTX_new()) == NULL) { ret = -1; goto err; }
BN_CTX_start(ctx);
order = BN_CTX_get(ctx);
if (!EC_GROUP_get_order(group, order, ctx)) { ret = -2; goto err; }
x = BN_CTX_get(ctx);
if (!BN_copy(x, order)) { ret=-1; goto err; }
if (!BN_mul_word(x, i)) { ret=-1; goto err; }
if (!BN_add(x, x, ecsig->r)) { ret=-1; goto err; }
field = BN_CTX_get(ctx);
if (!EC_GROUP_get_curve_GFp(group, field, NULL, NULL, ctx)) { ret=-2; goto err; }
if (BN_cmp(x, field) >= 0) { ret=0; goto err; }
if ((R = EC_POINT_new(group)) == NULL) { ret = -2; goto err; }
if (!EC_POINT_set_compressed_coordinates_GFp(group, R, x, recid % 2, ctx)) { ret=0; goto err; }
if (check)
{
if ((O = EC_POINT_new(group)) == NULL) { ret = -2; goto err; }
if (!EC_POINT_mul(group, O, NULL, R, order, ctx)) { ret=-2; goto err; }
if (!EC_POINT_is_at_infinity(group, O)) { ret = 0; goto err; }
}
if ((Q = EC_POINT_new(group)) == NULL) { ret = -2; goto err; }
n = EC_GROUP_get_degree(group);
e = BN_CTX_get(ctx);
if (!BN_bin2bn(msg, msglen, e)) { ret=-1; goto err; }
if (8*msglen > n) BN_rshift(e, e, 8-(n & 7));
zero = BN_CTX_get(ctx);
if (!BN_zero(zero)) { ret=-1; goto err; }
if (!BN_mod_sub(e, zero, e, order, ctx)) { ret=-1; goto err; }
rr = BN_CTX_get(ctx);
if (!BN_mod_inverse(rr, ecsig->r, order, ctx)) { ret=-1; goto err; }
sor = BN_CTX_get(ctx);
if (!BN_mod_mul(sor, ecsig->s, rr, order, ctx)) { ret=-1; goto err; }
eor = BN_CTX_get(ctx);
if (!BN_mod_mul(eor, e, rr, order, ctx)) { ret=-1; goto err; }
if (!EC_POINT_mul(group, Q, eor, R, sor, ctx)) { ret=-2; goto err; }
if (!EC_KEY_set_public_key(eckey, Q)) { ret=-2; goto err; }
ret = 1;
err:
if (ctx) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (R != NULL) EC_POINT_free(R);
if (O != NULL) EC_POINT_free(O);
if (Q != NULL) EC_POINT_free(Q);
return ret;
}
}
public_key::public_key() {}
public_key::public_key( const public_key& pk ) : my( pk.my ) {}
public_key::public_key( public_key&& pk ) : my( std::move( pk.my ) ) {}
public_key::~public_key() {}
public_key& public_key::operator=( public_key&& pk )
{
my = std::move(pk.my);
return *this;
}
public_key& public_key::operator=( const public_key& pk )
{
my = pk.my;
return *this;
}
bool public_key::valid()const
{
return my->_key != nullptr;
}
/* WARNING! This implementation is broken, it is actually equivalent to
* public_key::add()!
*/
// public_key public_key::mult( const fc::sha256& digest ) const
// {
// // get point from this public key
// const EC_POINT* master_pub = EC_KEY_get0_public_key( my->_key );
// ec_group group(EC_GROUP_new_by_curve_name(NID_secp256k1));
//
// ssl_bignum z;
// BN_bin2bn((unsigned char*)&digest, sizeof(digest), z);
//
// // multiply by digest
// ssl_bignum one;
// BN_one(one);
// bn_ctx ctx(BN_CTX_new());
//
// ec_point result(EC_POINT_new(group));
// EC_POINT_mul(group, result, z, master_pub, one, ctx);
//
// public_key rtn;
// rtn.my->_key = EC_KEY_new_by_curve_name( NID_secp256k1 );
// EC_KEY_set_public_key(rtn.my->_key,result);
//
// return rtn;
// }
public_key public_key::add( const fc::sha256& digest )const
{
try {
ec_group group(EC_GROUP_new_by_curve_name(NID_secp256k1));
bn_ctx ctx(BN_CTX_new());
fc::bigint digest_bi( (char*)&digest, sizeof(digest) );
ssl_bignum order;
EC_GROUP_get_order(group, order, ctx);
if( digest_bi > fc::bigint(order) )
{
FC_THROW_EXCEPTION( exception, "digest > group order" );
}
public_key digest_key = private_key::regenerate(digest).get_public_key();
const EC_POINT* digest_point = EC_KEY_get0_public_key( digest_key.my->_key );
// get point from this public key
const EC_POINT* master_pub = EC_KEY_get0_public_key( my->_key );
// ssl_bignum z;
// BN_bin2bn((unsigned char*)&digest, sizeof(digest), z);
// multiply by digest
// ssl_bignum one;
// BN_one(one);
ec_point result(EC_POINT_new(group));
EC_POINT_add(group, result, digest_point, master_pub, ctx);
if (EC_POINT_is_at_infinity(group, result))
{
FC_THROW_EXCEPTION( exception, "point at infinity" );
}
public_key rtn;
rtn.my->_key = EC_KEY_new_by_curve_name( NID_secp256k1 );
EC_KEY_set_public_key(rtn.my->_key,result);
return rtn;
} FC_RETHROW_EXCEPTIONS( debug, "digest: ${digest}", ("digest",digest) );
}
std::string public_key::to_base58() const
{
public_key_data key = serialize();
return to_base58( key );
}
// signature private_key::sign( const fc::sha256& digest )const
// {
// unsigned int buf_len = ECDSA_size(my->_key);
//// fprintf( stderr, "%d %d\n", buf_len, sizeof(sha256) );
// signature sig;
// assert( buf_len == sizeof(sig) );
//
// if( !ECDSA_sign( 0,
// (const unsigned char*)&digest, sizeof(digest),
// (unsigned char*)&sig, &buf_len, my->_key ) )
// {
// FC_THROW_EXCEPTION( exception, "signing error" );
// }
//
//
// return sig;
// }
// bool public_key::verify( const fc::sha256& digest, const fc::ecc::signature& sig )
// {
// return 1 == ECDSA_verify( 0, (unsigned char*)&digest, sizeof(digest), (unsigned char*)&sig, sizeof(sig), my->_key );
// }
public_key_data public_key::serialize()const
{
public_key_data dat;
if( !my->_key ) return dat;
EC_KEY_set_conv_form( my->_key, POINT_CONVERSION_COMPRESSED );
/*size_t nbytes = i2o_ECPublicKey( my->_key, nullptr ); */
/*assert( nbytes == 33 )*/
char* front = &dat.data[0];
i2o_ECPublicKey( my->_key, (unsigned char**)&front ); // FIXME: questionable memory handling
return dat;
/*
EC_POINT* pub = EC_KEY_get0_public_key( my->_key );
EC_GROUP* group = EC_KEY_get0_group( my->_key );
EC_POINT_get_affine_coordinates_GFp( group, pub, self.my->_pub_x.get(), self.my->_pub_y.get(), nullptr );
*/
}
public_key_point_data public_key::serialize_ecc_point()const
{
public_key_point_data dat;
if( !my->_key ) return dat;
EC_KEY_set_conv_form( my->_key, POINT_CONVERSION_UNCOMPRESSED );
char* front = &dat.data[0];
i2o_ECPublicKey( my->_key, (unsigned char**)&front ); // FIXME: questionable memory handling
return dat;
}
public_key::public_key( const public_key_point_data& dat )
{
const char* front = &dat.data[0];
if( *front == 0 ){}
else
{
my->_key = EC_KEY_new_by_curve_name( NID_secp256k1 );
my->_key = o2i_ECPublicKey( &my->_key, (const unsigned char**)&front, sizeof(dat) );
if( !my->_key )
{
FC_THROW_EXCEPTION( exception, "error decoding public key", ("s", ERR_error_string( ERR_get_error(), nullptr) ) );
}
}
}
public_key::public_key( const public_key_data& dat )
{
const char* front = &dat.data[0];
if( *front == 0 ){}
else
{
my->_key = EC_KEY_new_by_curve_name( NID_secp256k1 );
my->_key = o2i_ECPublicKey( &my->_key, (const unsigned char**)&front, sizeof(public_key_data) );
if( !my->_key )
{
FC_THROW_EXCEPTION( exception, "error decoding public key", ("s", ERR_error_string( ERR_get_error(), nullptr) ) );
}
}
}
// bool private_key::verify( const fc::sha256& digest, const fc::ecc::signature& sig )
// {
// return 1 == ECDSA_verify( 0, (unsigned char*)&digest, sizeof(digest), (unsigned char*)&sig, sizeof(sig), my->_key );
// }
public_key::public_key( const compact_signature& c, const fc::sha256& digest, bool check_canonical )
{
int nV = c.data[0];
if (nV<27 || nV>=35)
FC_THROW_EXCEPTION( exception, "unable to reconstruct public key from signature" );
ECDSA_SIG *sig = ECDSA_SIG_new();
BN_bin2bn(&c.data[1],32,sig->r);
BN_bin2bn(&c.data[33],32,sig->s);
if( check_canonical )
{
FC_ASSERT( is_canonical( c ), "signature is not canonical" );
}
my->_key = EC_KEY_new_by_curve_name(NID_secp256k1);
if (nV >= 31)
{
EC_KEY_set_conv_form( my->_key, POINT_CONVERSION_COMPRESSED );
nV -= 4;
// fprintf( stderr, "compressed\n" );
}
if (detail::public_key_impl::ECDSA_SIG_recover_key_GFp(my->_key, sig, (unsigned char*)&digest, sizeof(digest), nV - 27, 0) == 1)
{
ECDSA_SIG_free(sig);
return;
}
ECDSA_SIG_free(sig);
FC_THROW_EXCEPTION( exception, "unable to reconstruct public key from signature" );
}
}}