Sheriff is the most secure software-based system available. If you incorporate the Sheriff Licence System Application Programming Interface (SLSAPI) functions in your application, you can deter licence system tampering and reveal when tampering occurs. The security model employed by Sheriff aims to stop an intruder's attack in all areas. The model comprises of three components: encrypted licence key, encrypted licence file and encrypted Application-SLSAPI communication channel. Encrypted Application-SLSAPI communication channel is accomplished by including a challenge/response protocol in the calls to the SLSAPI functions. It provides a very reliable way for both the licence system and the application to verify that the other is a legitimate party. It also provides a reliable encryption system to prevent the communication parameter between the application and the API from being modified en-route. The SLSAPI functions use the MD5 Message-Digest Algorithm to implement the challenge/response protocol. This algorithm does not require patented cryptographic techniques. Knowledge of the algorithm neither compromises the secrets the application passes through it nor the level of security the SLSAPI offers. |