Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.ambari.server.security.encryption; import org.apache.commons.io.FileUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.ByteArrayInputStream; import java.io.File; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.security.cert.CertificateException; import java.security.cert.CertificateFactory; import java.security.cert.X509Certificate; import java.security.interfaces.RSAPublicKey; /** * Utility class containing methods to works with certificates */ public class CertificateUtils { private static final Logger LOG = LoggerFactory.getLogger(CertificateUtils.class); /** * Get RSA public key from X.509 certificate file * @param filePath path to certificate file * @return RSA public key * @throws IOException * @throws CertificateException */ public static RSAPublicKey getPublicKeyFromFile(String filePath) throws IOException, CertificateException { String pemString = FileUtils.readFileToString(new File(filePath)); return getPublicKeyFromString(pemString); } /** * Get RSA public key from X.509 certificate string (full crt file content, including header and footer) * @param certificateString certificate string * @return RSA public key * @throws CertificateException * @throws UnsupportedEncodingException */ public static RSAPublicKey getPublicKeyFromString(String certificateString) throws CertificateException, UnsupportedEncodingException { CertificateFactory fact = CertificateFactory.getInstance("X.509"); ByteArrayInputStream is = new ByteArrayInputStream(certificateString.getBytes("UTF8")); X509Certificate cer = (X509Certificate) fact.generateCertificate(is); return (RSAPublicKey) cer.getPublicKey(); } }