@AccessesPartialKey
  public static PublicKeyVerify create(RsaSsaPkcs1PublicKey key) throws GeneralSecurityException {
    KeyFactory kf = EngineFactory.KEY_FACTORY.getInstance("RSA");
    RSAPublicKey publicKey =
        (RSAPublicKey)
            kf.generatePublic(
                new RSAPublicKeySpec(key.getModulus(), key.getParameters().getPublicExponent()));

    return new RsaSsaPkcs1VerifyJce(
        publicKey,
        HASH_TYPE_CONVERTER.toProtoEnum(key.getParameters().getHashType()),
        key.getOutputPrefix().toByteArray(),
        key.getParameters().getVariant().equals(RsaSsaPkcs1Parameters.Variant.LEGACY)
            ? new byte[] {0}
            : new byte[0]);
  }
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