private byte[] toAsnPrefix(HashType hash) throws GeneralSecurityException {
    switch (hash) {
      case SHA256:
        return Hex.decode(ASN_PREFIX_SHA256);
      case SHA384:
        return Hex.decode(ASN_PREFIX_SHA384);
      case SHA512:
        return Hex.decode(ASN_PREFIX_SHA512);
      default:
        throw new GeneralSecurityException("Unsupported hash " + hash);
    }
  }
RsaSsaPkcs1 (i.e. RSA Signature Schemes with Appendix (SSA) using PKCS1-v1_5 encoding) verifying
with JCE.
java_src/src/main/java/com/google/crypto/tink/subtle/RsaSsaPkcs1VerifyJce.java