Storing any random byte array into a UTF-8 string causes invalid characters to be replaced with hex value FFFD. 2 nodes on different JVMs using ENCRYPT may not be able to communicate because they calculate different MD5 digest values.

Main thread:
http://old.nabble.com/ENCRYPT-puts-illegal-chars-into-UTF-8-String-seems-to-be-unintended--td31497430.html#a31524432

More description of why UTF-8 does this recplacement:
http://en.wikipedia.org/wiki/UTF-8

The fix will possibly make older versions of ENCRYPT incompatible since it will change the calculated MD5 digest value.

To fix it, ENCRYPT should be changed from this:
private void initSymCiphers(String algorithm, SecretKey secret) throws Exception {

...
symVersion=new String(digest.digest(), "UTF-8");
...
}

To something like this (byteArrayToHexString() copied from http://jkmessenger.googlecode.com/svn-history/r8/trunk/CryptoUtils.java):
private void initSymCiphers(String algorithm, SecretKey secret) throws Exception {
...
symVersion = byteArrayToHexString(digest.digest())
...

public static String byteArrayToHexString(byte[] b){
StringBuffer sb = new StringBuffer(b.length * 2);
for (int i = 0; i < b.length; i++){
int v = b[i] & 0xff;
if (v < 16)

sb.append(Integer.toHexString(v));
}
return sb.toString().toUpperCase();
}