com.vmware.xenon.common.PrivateKeyReader Maven / Gradle / Ivy
/*
* Copyright (c) 2014-2016 VMware, Inc. All Rights Reserved.
*
* 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 com.vmware.xenon.common;
import static java.util.stream.Collectors.joining;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.security.AlgorithmParameters;
import java.security.Key;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.spec.KeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Base64;
import java.util.Base64.Decoder;
import java.util.List;
import javax.crypto.Cipher;
import javax.crypto.EncryptedPrivateKeyInfo;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
/**
* Read private key file(PKCS#8).
*/
public final class PrivateKeyReader {
private PrivateKeyReader() {
}
/**
* Retrieve {@link PrivateKey} from PEM encoded PKCS#8 file.
*
* @param path path to the PKCS#8 PEM file
* @param password null if not encrypted
* @return
*/
public static PrivateKey fromPem(Path path, String password) {
PrivateKey privateKey;
try {
byte[] der = getDer(path);
KeySpec keySpec = getKeySpec(der, password);
KeyFactory kf = KeyFactory.getInstance("RSA");
privateKey = kf.generatePrivate(keySpec);
} catch (Exception e) {
String msg = String.format("Failed to read PKCS#8 PEM file. file=%s", path);
Utils.logWarning(msg);
throw new RuntimeException(msg, e);
}
return privateKey;
}
/**
* Convert PKCS#8 PEM file to DER encoded private key
*/
private static byte[] getDer(Path path) throws IOException {
List lines = Files.readAllLines(path);
// remove header and footer, combine to single string without line breaks
String base64Text = lines.subList(1, lines.size() - 1).stream().collect(joining());
Decoder decoder = Base64.getDecoder();
return decoder.decode(base64Text);
}
private static KeySpec getKeySpec(byte[] encodedKey, String password) throws Exception {
KeySpec keySpec;
if (password == null) {
keySpec = new PKCS8EncodedKeySpec(encodedKey);
} else {
// decrypt private key
PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray());
EncryptedPrivateKeyInfo privateKeyInfo = new EncryptedPrivateKeyInfo(encodedKey);
String algorithmName = privateKeyInfo.getAlgName();
Cipher cipher = Cipher.getInstance(algorithmName);
SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance(algorithmName);
Key pbeKey = secretKeyFactory.generateSecret(pbeKeySpec);
AlgorithmParameters algParams = privateKeyInfo.getAlgParameters();
cipher.init(Cipher.DECRYPT_MODE, pbeKey, algParams);
keySpec = privateKeyInfo.getKeySpec(cipher);
}
return keySpec;
}
}