Thursday, 15 March 2012 16:07

eSSP Encrypted Smiley Secure Protocol

What is eSSP?

The encryption of SSP (Smiley Secure Protocol) ensures superior protection and reliability of the data, which is transferred between validator and host machine. The encryption key is 128 bits long, and is divided into two parts. The lower 64 bits are fixed and specified by the machine manufacturer, allowing the manufacturer to control which devices are used in their machines. The higher 64 bits are securely negotiated by the slave and host at power up, ensuring each machine and each session are using different keys. This encryption algorithm is approved by the US military for its advanced security.

eSSP is a secure serial interface specifically designed to address the problems experienced by cash systems in gaming machines. Problems such as acceptor swapping, reprogramming acceptors and line tapping are all addressed. This interface is recommended for all new designs. The interface uses a master slave model; the host machine is the master and the peripherals (note acceptor, coin acceptor or coin hopper) are the slaves. Data transfer is over a multi-drop bus using clock asynchronous serial transmission with simple open collector drivers.

The integrity of data transfers is ensured through the use of 16 bit CRC checksums on all packets. Each SSP device of a particular type has a unique serial number; this number is used to validate each device in the direction of credit transfer before transactions can take place. Commands are currently provided for coin acceptors, note acceptors and coin hoppers. All current features of these devices are supported.

To help in the software implementation of eSSP, ITL can provide DLL controls and Visual Basic applications on request. Please contact This email address is being protected from spambots. You need JavaScript enabled to view it.  for more information.