public static final EMSA_PKCS1_V1_5 getInstance(final String mdName) {
      final IMessageDigest hash = HashFactory.getInstance(mdName);
      final String name = hash.name();
      if (!(name.equals(Registry.MD2_HASH)
            || name.equals(Registry.MD5_HASH)
            || name.equals(Registry.SHA160_HASH)
            || name.equals(Registry.SHA256_HASH)
            || name.equals(Registry.SHA384_HASH)
            || name.equals(Registry.SHA512_HASH))) {
         throw new UnsupportedOperationException("hash with no ID");
      }
      return new EMSA_PKCS1_V1_5(hash);
   }