Java tutorial
/* * Copyright 2017-2018 the original author or authors. * * Licensed 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.cloudfoundry.security; import org.bouncycastle.asn1.pkcs.PrivateKeyInfo; import org.bouncycastle.openssl.PEMKeyPair; import org.bouncycastle.openssl.PEMParser; import org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter; import java.io.IOException; import java.io.Reader; import java.nio.charset.StandardCharsets; import java.nio.file.Files; import java.nio.file.Path; import java.security.PrivateKey; final class PrivateKeyFactory { private static final JcaPEMKeyConverter CONVERTER = new JcaPEMKeyConverter(); static PrivateKey generate(Path path) throws IOException { try (Reader in = Files.newBufferedReader(path, StandardCharsets.UTF_8)) { PEMParser parser = new PEMParser(in); Object keyPair = parser.readObject(); if (!(keyPair instanceof PEMKeyPair)) { throw new IllegalStateException( String.format("%s contains an artifact that is not a key pair: %s", path, keyPair)); } PrivateKeyInfo privateKeyInfo = ((PEMKeyPair) keyPair).getPrivateKeyInfo(); if (privateKeyInfo == null) { throw new IllegalStateException(String.format("%s does not contain a private key", path)); } return CONVERTER.getPrivateKey(privateKeyInfo); } } }