* A hash is a one-way function -- that is, given an * input, an output is easily computed. However, given the output, the * input is almost impossible to compute. This is useful for passwords * since we can store the hash and a hacker will then have a very hard time * determining the original password. * * @param data the String to compute the hash of. * @return a hashed version of the passed-in String */ public synchronized static final String hash(String data) { if (digest == null) { try { digest = MessageDigest.getInstance("SHA-1"); } catch (NoSuchAlgorithmException nsae) { System.err.println("Failed to load the SHA-1 MessageDigest. " + "Jive will be unable to function normally."); } } // Now, compute hash. try { digest.update(data.getBytes("UTF-8")); } catch (UnsupportedEncodingException e) { System.err.println(e); } return encodeHex(digest.digest()); } /** * Turns an array of bytes into a String representing each byte as an * unsigned hex number. *
* Method by Santeri Paavolainen, Helsinki Finland 1996
* (c) Santeri Paavolainen, Helsinki Finland 1996
* Distributed under LGPL.
*
* @param bytes an array of bytes to convert to a hex-string
* @return generated hex string
*/
public static final String encodeHex(byte[] bytes) {
StringBuffer buf = new StringBuffer(bytes.length * 2);
int i;
for (i = 0; i < bytes.length; i++) {
if (((int) bytes[i] & 0xff) < 0x10) {
buf.append("0");
}
buf.append(Long.toString((int) bytes[i] & 0xff, 16));
}
return buf.toString();
}
//*********************************************************************
//* Base64 - a simple base64 encoder and decoder.
//*
//* Copyright (c) 1999, Bob Withers - bwit@pobox.com
//*
//* This code may be freely used for any purpose, either personal
//* or commercial, provided the authors copyright notice remains
//* intact.
//*********************************************************************
private static final int fillchar = '=';
private static final String cvt = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+ "0123456789+/";
/**
* Encodes a String as a base64 String.
*
* @param data a String to encode.
* @return a base64 encoded String.
*/
public static String encodeBase64(String data) {
byte [] bytes = null;
try {
bytes = data.getBytes("UTF8");
}
catch (UnsupportedEncodingException uee) {
uee.printStackTrace();
}
return encodeBase64(bytes);
}
/**
* Encodes a byte array into a base64 String.
*
* @param data a byte array to encode.
* @return a base64 encode String.
*/
public static String encodeBase64(byte[] data) {
int c;
int len = data.length;
StringBuffer ret = new StringBuffer(((len / 3) + 1) * 4);
for (int i = 0; i < len; ++i) {
c = (data[i] >> 2) & 0x3f;
ret.append(cvt.charAt(c));
c = (data[i] << 4) & 0x3f;
if (++i < len)
c |= (data[i] >> 4) & 0x0f;
ret.append(cvt.charAt(c));
if (i < len) {
c = (data[i] << 2) & 0x3f;
if (++i < len)
c |= (data[i] >> 6) & 0x03;
ret.append(cvt.charAt(c));
}
else {
++i;
ret.append((char) fillchar);
}
if (i < len) {
c = data[i] & 0x3f;
ret.append(cvt.charAt(c));
}
else {
ret.append((char) fillchar);
}
}
return ret.toString();
}
/**
* Decodes a base64 String.
*
* @param data a base64 encoded String to decode.
* @return the decoded String.
*/
public static byte[] decodeBase64(String data) {
byte [] bytes = null;
try {
bytes = data.getBytes("UTF8");
return decodeBase64(bytes).getBytes("UTF8");
}
catch (UnsupportedEncodingException uee) {
uee.printStackTrace();
}
return new byte[] { };
}
/**
* Decodes a base64 aray of bytes.
*
* @param data a base64 encode byte array to decode.
* @return the decoded String.
*/
private static String decodeBase64(byte[] data) {
int c, c1;
int len = data.length;
StringBuffer ret = new StringBuffer((len * 3) / 4);
for (int i = 0; i < len; ++i) {
c = cvt.indexOf(data[i]);
++i;
c1 = cvt.indexOf(data[i]);
c = ((c << 2) | ((c1 >> 4) & 0x3));
ret.append((char) c);
if (++i < len) {
c = data[i];
if (fillchar == c)
break;
c = cvt.indexOf(c);
c1 = ((c1 << 4) & 0xf0) | ((c >> 2) & 0xf);
ret.append((char) c1);
}
if (++i < len) {
c1 = data[i];
if (fillchar == c1)
break;
c1 = cvt.indexOf(c1);
c = ((c << 6) & 0xc0) | c1;
ret.append((char) c);
}
}
return ret.toString();
}
/**
* Pseudo-random number generator object for use with randomString().
* The Random class is not considered to be cryptographically secure, so
* only use these random Strings for low to medium security applications.
*/
private static Random randGen = new Random();
/**
* Array of numbers and letters of mixed case. Numbers appear in the list
* twice so that there is a more equal chance that a number will be picked.
* We can use the array to get a random number or letter by picking a random
* array index.
*/
private static char[] numbersAndLetters = ("0123456789abcdefghijklmnopqrstuvwxyz" +
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ").toCharArray();
/**
* Returns a random String of numbers and letters (lower and upper case)
* of the specified length. The method uses the Random class that is
* built-in to Java which is suitable for low to medium grade security uses.
* This means that the output is only pseudo random, i.e., each number is
* mathematically generated so is not truly random.
* * The specified length must be at least one. If not, the method will return * null. * * @param length the desired length of the random String to return. * @return a random String of numbers and letters of the specified length. */ public static final String randomString(int length) { if (length < 1) { return null; } // Create a char buffer to put random letters and numbers in. char [] randBuffer = new char[length]; for (int i=0; i