303 lines
12 KiB
C++
303 lines
12 KiB
C++
#include <fc/crypto/elliptic.hpp>
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#include <fc/crypto/base58.hpp>
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#include <fc/crypto/hmac.hpp>
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#include <fc/crypto/openssl.hpp>
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#include <fc/crypto/sha512.hpp>
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#include <fc/fwd_impl.hpp>
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#include <fc/exception/exception.hpp>
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#include <fc/log/logger.hpp>
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#include <assert.h>
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#include <secp256k1.h>
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#if _WIN32
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# include <malloc.h>
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#else
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# include <alloca.h>
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#endif
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#include "_elliptic_impl_priv.hpp"
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namespace fc { namespace ecc {
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namespace detail
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{
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const secp256k1_context_t* _get_context() {
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static secp256k1_context_t* ctx = secp256k1_context_create(SECP256K1_CONTEXT_VERIFY | SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_RANGEPROOF | SECP256K1_CONTEXT_COMMIT );
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return ctx;
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}
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void _init_lib() {
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static const secp256k1_context_t* ctx = _get_context();
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(void)ctx;
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static int init_o = init_openssl();
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(void)init_o;
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}
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class public_key_impl
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{
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public:
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public_key_impl() BOOST_NOEXCEPT
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{
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_init_lib();
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memset( _key.data(), 0, _key.size() );
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}
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public_key_impl( const public_key_impl& cpy ) BOOST_NOEXCEPT
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: _key( cpy._key )
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{
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_init_lib();
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}
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public_key_data _key;
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};
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typedef std::array<char,37> chr37;
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chr37 _derive_message( const public_key_data& key, int i );
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fc::sha256 _left( const fc::sha512& v );
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fc::sha256 _right( const fc::sha512& v );
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const ec_group& get_curve();
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const private_key_secret& get_curve_order();
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const private_key_secret& get_half_curve_order();
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} // detail
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static const public_key_data empty_pub = detail::public_key_impl()._key;
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static const private_key_secret empty_priv;
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fc::sha512 private_key::get_shared_secret( const public_key& other )const
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{
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FC_ASSERT( my->_key != empty_priv );
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FC_ASSERT( other.my->_key != empty_pub );
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public_key_data pub(other.my->_key);
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FC_ASSERT( secp256k1_ec_pubkey_tweak_mul( detail::_get_context(), pub.begin(), pub.size(), (unsigned char*) my->_key.data() ) );
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return fc::sha512::hash( (char*) pub.begin() + 1, pub.size() - 1 );
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}
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public_key::public_key() {}
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public_key::public_key( const public_key &pk ) : my( pk.my ) {}
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public_key::public_key( public_key &&pk ) : my( std::move( pk.my ) ) {}
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public_key::~public_key() {}
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public_key& public_key::operator=( const public_key& pk )
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{
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my = pk.my;
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return *this;
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}
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public_key& public_key::operator=( public_key&& pk )
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{
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my = pk.my;
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return *this;
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}
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bool public_key::valid()const
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{
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return my->_key != empty_pub;
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}
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public_key public_key::add( const fc::sha256& digest )const
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{
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FC_ASSERT( my->_key != empty_pub );
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public_key_data new_key;
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memcpy( new_key.begin(), my->_key.begin(), new_key.size() );
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FC_ASSERT( secp256k1_ec_pubkey_tweak_add( detail::_get_context(), new_key.begin(), new_key.size(), (unsigned char*) digest.data() ) );
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return public_key( new_key );
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}
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std::string public_key::to_base58() const
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{
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FC_ASSERT( my->_key != empty_pub );
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return to_base58( my->_key );
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}
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public_key_data public_key::serialize()const
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{
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FC_ASSERT( my->_key != empty_pub );
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return my->_key;
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}
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public_key_point_data public_key::serialize_ecc_point()const
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{
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FC_ASSERT( my->_key != empty_pub );
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public_key_point_data dat;
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unsigned int pk_len = my->_key.size();
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memcpy( dat.begin(), my->_key.begin(), pk_len );
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FC_ASSERT( secp256k1_ec_pubkey_decompress( detail::_get_context(), dat.begin(), (int*) &pk_len ) );
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FC_ASSERT( pk_len == dat.size() );
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return dat;
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}
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public_key::public_key( const public_key_point_data& dat )
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{
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const unsigned char* front = dat.data();
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if( *front == 0 ){}
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else
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{
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EC_KEY *key = EC_KEY_new_by_curve_name( NID_secp256k1 );
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key = o2i_ECPublicKey( &key, &front, sizeof(dat) );
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FC_ASSERT( key );
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EC_KEY_set_conv_form( key, POINT_CONVERSION_COMPRESSED );
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unsigned char* buffer = my->_key.begin();
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i2o_ECPublicKey( key, &buffer ); // FIXME: questionable memory handling
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EC_KEY_free( key );
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}
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}
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public_key::public_key( const public_key_data& dat )
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{
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my->_key = dat;
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}
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public_key::public_key( const compact_signature& c, const fc::sha256& digest, bool check_canonical )
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{
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int nV = c[0];
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if (nV<27 || nV>=35)
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FC_THROW_EXCEPTION( exception, "unable to reconstruct public key from signature" );
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if( check_canonical )
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{
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FC_ASSERT( is_canonical( c ), "signature is not canonical" );
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}
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unsigned int pk_len;
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FC_ASSERT( secp256k1_ecdsa_recover_compact( detail::_get_context(), (unsigned char*) digest.data(), c.begin() + 1, my->_key.begin(), (int*) &pk_len, 1, (*c.begin() - 27) & 3 ) );
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FC_ASSERT( pk_len == my->_key.size() );
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}
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extended_public_key::extended_public_key( const public_key& k, const fc::sha256& c,
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int child, int parent, uint8_t depth )
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: public_key(k), c(c), child_num(child), parent_fp(parent), depth(depth) { }
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extended_public_key extended_public_key::derive_normal_child(int i) const
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{
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hmac_sha512 mac;
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public_key_data key = serialize();
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const detail::chr37 data = detail::_derive_message( key, i );
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fc::sha512 l = mac.digest( c.data(), c.data_size(), data.begin(), data.size() );
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fc::sha256 left = detail::_left(l);
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FC_ASSERT( left < detail::get_curve_order() );
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FC_ASSERT( secp256k1_ec_pubkey_tweak_add( detail::_get_context(), key.begin(), key.size(), (unsigned char*) left.data() ) > 0 );
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// FIXME: check validity - if left + key == infinity then invalid
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extended_public_key result( key, detail::_right(l), i, fingerprint(), depth + 1 );
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return result;
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}
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extended_private_key::extended_private_key( const private_key& k, const sha256& c,
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int child, int parent, uint8_t depth )
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: private_key(k), c(c), child_num(child), parent_fp(parent), depth(depth) { }
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extended_private_key extended_private_key::private_derive_rest( const fc::sha512& hash,
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int i) const
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{
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fc::sha256 left = detail::_left(hash);
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FC_ASSERT( left < detail::get_curve_order() );
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FC_ASSERT( secp256k1_ec_privkey_tweak_add( detail::_get_context(), (unsigned char*) left.data(), (unsigned char*) get_secret().data() ) > 0 );
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extended_private_key result( private_key::regenerate( left ), detail::_right(hash),
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i, fingerprint(), depth + 1 );
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return result;
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}
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commitment_type blind( const blind_factor_type& blind, uint64_t value )
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{
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commitment_type result;
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FC_ASSERT( secp256k1_pedersen_commit( detail::_get_context(), result.data(), (unsigned char*) blind.data(), value ) );
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return result;
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}
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blind_factor_type blind_sum( const std::vector<blind_factor_type>& blinds_in, uint32_t non_neg )
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{
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blind_factor_type result;
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std::vector<const unsigned char*> blinds(blinds_in.size());
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for( uint32_t i = 0; i < blinds_in.size(); ++i ) blinds[i] = (unsigned char*) blinds_in[i].data();
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FC_ASSERT( secp256k1_pedersen_blind_sum( detail::_get_context(), (unsigned char*) result.data(), blinds.data(), blinds_in.size(), non_neg ) );
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return result;
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}
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/** verifies taht commnits + neg_commits + excess == 0 */
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bool verify_sum( const std::vector<commitment_type>& commits_in, const std::vector<commitment_type>& neg_commits_in, int64_t excess )
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{
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std::vector<const unsigned char*> commits(commits_in.size());
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for( uint32_t i = 0; i < commits_in.size(); ++i ) commits[i] = commits_in[i].data();
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std::vector<const unsigned char*> neg_commits(neg_commits_in.size());
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for( uint32_t i = 0; i < neg_commits_in.size(); ++i ) neg_commits[i] = neg_commits_in[i].data();
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return secp256k1_pedersen_verify_tally( detail::_get_context(), commits.data(), commits.size(), neg_commits.data(), neg_commits.size(), excess );
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}
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bool verify_range( uint64_t& min_val, uint64_t& max_val, const commitment_type& commit, const std::vector<char>& proof )
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{
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return secp256k1_rangeproof_verify( detail::_get_context(), &min_val, &max_val, commit.data(), (const unsigned char*)proof.data(), proof.size() );
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}
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std::vector<char> range_proof_sign( uint64_t min_value,
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const commitment_type& commit,
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const blind_factor_type& commit_blind,
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const blind_factor_type& nonce,
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int8_t base10_exp,
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uint8_t min_bits,
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uint64_t actual_value
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)
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{
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int proof_len = 5134;
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std::vector<char> proof(proof_len);
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FC_ASSERT( secp256k1_rangeproof_sign( detail::_get_context(),
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(unsigned char*)proof.data(),
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&proof_len, min_value,
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commit.data(),
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(unsigned char*) commit_blind.data(),
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(unsigned char*) nonce.data(),
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base10_exp, min_bits, actual_value ) );
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proof.resize(proof_len);
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return proof;
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}
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bool verify_range_proof_rewind( blind_factor_type& blind_out,
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uint64_t& value_out,
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string& message_out,
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const blind_factor_type& nonce,
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uint64_t& min_val,
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uint64_t& max_val,
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commitment_type commit,
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const std::vector<char>& proof )
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{
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char msg[4096];
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int mlen = 0;
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FC_ASSERT( secp256k1_rangeproof_rewind( detail::_get_context(),
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(unsigned char*) blind_out.data(),
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&value_out,
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(unsigned char*) msg,
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&mlen,
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(unsigned char*) nonce.data(),
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&min_val,
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&max_val,
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commit.data(),
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(const unsigned char*)proof.data(),
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proof.size() ) );
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message_out = std::string( msg, mlen );
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return true;
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}
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range_proof_info range_get_info( const std::vector<char>& proof )
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{
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range_proof_info result;
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FC_ASSERT( secp256k1_rangeproof_info( detail::_get_context(),
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(int*)&result.exp,
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(int*)&result.mantissa,
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(uint64_t*)&result.min_value,
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(uint64_t*)&result.max_value,
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(const unsigned char*)proof.data(),
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(int)proof.size() ) );
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return result;
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}
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} }
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