/**
* Returns an MD5 hash.
*
* @param pw String
* @return String
*/
private static String md5(final String pw) {
final StringBuilder sb = new StringBuilder();
try {
final MessageDigest md = MessageDigest.getInstance("MD5");
md.update(pw.getBytes());
for (final byte b : md.digest()) {
final String s = Integer.toHexString(b & 0xFF);
if (s.length() == 1) sb.append('0');
sb.append(s);
}
} catch (final NoSuchAlgorithmException ex) {
// should not occur
ex.printStackTrace();
}
return sb.toString();
}
/**
* Compute the hash an IP address. The hash is the first 8 bytes of the SHA digest of the IP
* address.
*/
private static byte[] computeAddressHash() {
/*
* Get the local host's IP address.
*/
byte[] addr =
(byte[])
java.security.AccessController.doPrivileged(
new PrivilegedAction() {
public Object run() {
try {
return InetAddress.getLocalHost().getAddress();
} catch (Exception e) {
}
return new byte[] {0, 0, 0, 0};
}
});
byte[] addrHash;
final int ADDR_HASH_LENGTH = 8;
try {
/*
* Calculate message digest of IP address using SHA.
*/
MessageDigest md = MessageDigest.getInstance("SHA");
ByteArrayOutputStream sink = new ByteArrayOutputStream(64);
DataOutputStream out = new DataOutputStream(new DigestOutputStream(sink, md));
out.write(addr, 0, addr.length);
out.flush();
byte digest[] = md.digest();
int hashlength = Math.min(ADDR_HASH_LENGTH, digest.length);
addrHash = new byte[hashlength];
System.arraycopy(digest, 0, addrHash, 0, hashlength);
} catch (IOException ignore) {
/* can't happen, but be deterministic anyway. */
addrHash = new byte[0];
} catch (NoSuchAlgorithmException complain) {
throw new InternalError(complain.toString());
}
return addrHash;
}