/**
* Copyright (c) 2011-2017, James Zhan 詹波 (jfinal@126.com).
*
* 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.jfinal.kit;
import java.security.MessageDigest;
public class HashKit {
private static final java.security.SecureRandom random = new java.security.SecureRandom();
private static final char[] HEX_DIGITS = "0123456789abcdef".toCharArray();
private static final char[] CHAR_ARRAY = "_-0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray();
public static String md5(String srcStr){
return hash("MD5", srcStr);
}
public static String sha1(String srcStr){
return hash("SHA-1", srcStr);
}
public static String sha256(String srcStr){
return hash("SHA-256", srcStr);
}
public static String sha384(String srcStr){
return hash("SHA-384", srcStr);
}
public static String sha512(String srcStr){
return hash("SHA-512", srcStr);
}
public static String hash(String algorithm, String srcStr) {
try {
MessageDigest md = MessageDigest.getInstance(algorithm);
byte[] bytes = md.digest(srcStr.getBytes("utf-8"));
return toHex(bytes);
}
catch (Exception e) {
throw new RuntimeException(e);
}
}
private static String toHex(byte[] bytes) {
StringBuilder ret = new StringBuilder(bytes.length * 2);
for (int i=0; i<bytes.length; i++) {
ret.append(HEX_DIGITS[(bytes[i] >> 4) & 0x0f]);
ret.append(HEX_DIGITS[bytes[i] & 0x0f]);
}
return ret.toString();
}
/**
* md5 128bit 16bytes
* sha1 160bit 20bytes
* sha256 256bit 32bytes
* sha384 384bit 48bytes
* sha512 512bit 64bytes
*/
public static String generateSalt(int saltLength) {
StringBuilder salt = new StringBuilder();
for (int i=0; i<saltLength; i++) {
salt.append(CHAR_ARRAY[random.nextInt(CHAR_ARRAY.length)]);
}
return salt.toString();
}
public static String generateSaltForSha256() {
return generateSalt(32);
}
public static String generateSaltForSha512() {
return generateSalt(64);
}
public static boolean slowEquals(byte[] a, byte[] b) {
if (a == null || b == null) {
return false;
}
int diff = a.length ^ b.length;
for(int i=0; i<a.length && i<b.length; i++) {
diff |= a[i] ^ b[i];
}
return diff == 0;
}
}