/**
* 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.sqoop.util;
import java.rmi.server.UID;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* Securely generate random MD5 signatures for use as nonce values.
*/
public final class RandomHash {
private RandomHash() { }
/**
* Generate a new random md5 hash.
* @return a securely-generated random 16 byte sequence.
*/
public static byte [] generateMD5Bytes() {
try {
MessageDigest digester = MessageDigest.getInstance("MD5");
long time = System.currentTimeMillis();
digester.update((new UID() + "@" + time).getBytes());
return digester.digest();
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e);
}
}
/**
* Generate a new random md5 hash and convert it to a string.
* @return a securely-generated random string.
*/
public static String generateMD5String() {
byte [] bytes = generateMD5Bytes();
StringBuilder sb = new StringBuilder();
for (byte b : bytes) {
int x = ((int) b) & 0xFF;
sb.append(String.format("%02x", x));
}
return sb.toString();
}
}