this.pwVerificationBytes = new byte[ 2 ];
System.arraycopy( keyBytes, KEY_SIZE_BYTE*2, pwVerificationBytes, 0, 2 );
// create the first 16 bytes of the key sequence again (using pw+salt)
generator.init( pwBytes, saltBytes, ITERATION_COUNT );
cipherParameters = generator.generateDerivedParameters(KEY_SIZE_BIT);
// checksum added to the end of the encrypted data, update on each encryption call
this.mac = new HMac( new SHA1Digest() );
mac.init( new KeyParameter(authenticationCodeBytes) );