EC_Group::EC_Group(const BigInt& p,
                   const BigInt& a,
                   const BigInt& b,
                   const BigInt& base_x,
                   const BigInt& base_y,
                   const BigInt& order,
                   const BigInt& cofactor,
                   const OID& oid)
   {
   m_data = ec_group_data().lookup_or_create(p, a, b, base_x, base_y, order, cofactor, oid);
   }
EC_Group::EC_Group(const BigInt& p,
                   const BigInt& a,
                   const BigInt& b,
                   const BigInt& base_x,
                   const BigInt& base_y,
                   const BigInt& order,
                   const BigInt& cofactor,
                   const OID& oid)
   {
   m_data = ec_group_data().lookup_or_create(p, a, b, base_x, base_y, order, cofactor, oid);
   }