decrypt(gcry_mpi_t output, gcry_mpi_t a, gcry_mpi_t b, ELG_secret_key *skey )
{
  gcry_mpi_t t1 = mpi_alloc_secure( mpi_get_nlimbs( skey->p ) );

  /* output = b/(a^x) mod p */
  gcry_mpi_powm( t1, a, skey->x, skey->p );
  mpi_invm( t1, t1, skey->p );
  mpi_mulm( output, b, t1, skey->p );
#if 0
  if( DBG_CIPHER )
    {
      log_mpidump("elg decrypted x= ", skey->x);
      log_mpidump("elg decrypted p= ", skey->p);
      log_mpidump("elg decrypted a= ", a);
      log_mpidump("elg decrypted b= ", b);
      log_mpidump("elg decrypted M= ", output);
    }
#endif
  mpi_free(t1);
}
Unknown