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public class Md5Crypt {
/** The Identifier of the Apache variant. */
static final String APR1_PREFIX = "$apr1$";
/** The number of bytes of the final hash. */
private static final int BLOCKSIZE = 16;
/** The Identifier of this crypt() variant. */
static final String MD5_PREFIX = "$1$";
/** The number of rounds of the big loop. */
private static final int ROUNDS = 1000;
public static String md5Crypt(final byte[] keyBytes, final String salt, final String prefix) {
final int keyLen = keyBytes.length;
// Extract the real salt from the given string which can be a complete hash string.
String saltString;
if (salt == null) {
saltString = B64.getRandomSalt(8);
} else {
final Pattern p = Pattern.compile("^" + prefix.replace("$", "\\$") + "([\\.\\/a-zA-Z0-9]{1,8}).*");
final Matcher m = p.matcher(salt);
if (!m.find()) {
throw new IllegalArgumentException("Invalid salt value: " + salt);
}
saltString = m.group(1);
}
final byte[] saltBytes = saltString.getBytes(Charsets.UTF_8);
final MessageDigest ctx = DigestUtils.getMd5Digest();
/*
* The password first, since that is what is most unknown
*/
ctx.update(keyBytes);
/*
* Then our magic string
*/
ctx.update(prefix.getBytes(Charsets.UTF_8));
/*
* Then the raw salt
*/
ctx.update(saltBytes);
/*
* Then just as many characters of the MD5(pw,salt,pw)
*/
MessageDigest ctx1 = DigestUtils.getMd5Digest();
ctx1.update(keyBytes);
ctx1.update(saltBytes);
ctx1.update(keyBytes);
byte[] finalb = ctx1.digest();
int ii = keyLen;
while (ii > 0) {
ctx.update(finalb, 0, ii > 16 ? 16 : ii);
ii -= 16;
}
/*
* Don't leave anything around in vm they could use.
*/
Arrays.fill(finalb, (byte) 0);
/*
* Then something really weird...
*/
ii = keyLen;
final int j = 0;
while (ii > 0) {
if ((ii & 1) == 1) {
ctx.update(finalb[j]);
} else {
ctx.update(keyBytes[j]);
}
ii >>= 1;
}
/*
* Now make the output string
*/
final StringBuilder passwd = new StringBuilder(prefix + saltString + "$");
finalb = ctx.digest();
/*
* and now, just to make sure things don't run too fast On a 60 Mhz Pentium this takes 34 msec, so you would
* need 30 seconds to build a 1000 entry dictionary...
*/
for (int i = 0; i < ROUNDS; i++) {
ctx1 = DigestUtils.getMd5Digest();
if ((i & 1) != 0) {
ctx1.update(keyBytes);
} else {
ctx1.update(finalb, 0, BLOCKSIZE);
}
if (i % 3 != 0) {
ctx1.update(saltBytes);
}
if (i % 7 != 0) {
ctx1.update(keyBytes);
}
if ((i & 1) != 0) {
ctx1.update(finalb, 0, BLOCKSIZE);
} else {
ctx1.update(keyBytes);
}
finalb = ctx1.digest();
}
// The following was nearly identical to the Sha2Crypt code.
// Again, the buflen is not really needed.
// int buflen = MD5_PREFIX.length() - 1 + salt_string.length() + 1 + BLOCKSIZE + 1;
B64.b64from24bit(finalb[0], finalb[6], finalb[12], 4, passwd);
B64.b64from24bit(finalb[1], finalb[7], finalb[13], 4, passwd);
B64.b64from24bit(finalb[2], finalb[8], finalb[14], 4, passwd);
B64.b64from24bit(finalb[3], finalb[9], finalb[15], 4, passwd);
B64.b64from24bit(finalb[4], finalb[10], finalb[5], 4, passwd);
B64.b64from24bit((byte) 0, (byte) 0, finalb[11], 2, passwd);
/*
* Don't leave anything around in vm they could use.
*/
// Is there a better way to do this with the JVM?
ctx.reset();
ctx1.reset();
Arrays.fill(keyBytes, (byte) 0);
Arrays.fill(saltBytes, (byte) 0);
Arrays.fill(finalb, (byte) 0);
return passwd.toString();
}
}