private long encryptBlockCBC(long lPlainblock)
        {
            // chain with the CBC IV
            lPlainblock ^= m_lCBCIV;

            // encrypt the block
            lPlainblock = super.encryptBlock(lPlainblock);

            // the encrypted block is the new CBC IV
            return (m_lCBCIV = lPlainblock);
        }
cleans up all critical internals,
call this if you don't need an instance anymore
xmppserver/src/main/java/org/jivesoftware/util/Blowfish.java