Contents - Index

3.3 Security

  1. Encrypted Licence Key
  2. Encrypted Licence Database
  3. Encrypted and Challenged Communication Channels
  4. Anti-tampering Measures
  5. Anti-debug Measures
  6. Protected Licence Key Generator with Secret Codes

1. Encrypted Licence Key

The Sheriff Licence Key is dynamically encrypted, which means that the Licence Key changes every time it is generated even with the same Reference Code and licence policies. This is to prevent the Licence Key from being dissected. The Licence Key as well as the Reference Code are self-checked; any bit change to them causes them to become invalid.

2. Encrypted Licence database

The Sheriff licence database is encrypted and cannot be modified.

3. Encrypted and Challenged Communication Channels

The communication channel between an application and Sheriff is encrypted to prevent parameters being monitored or altered en-route. In addition, Sheriff employs a challenge/response protocol in calls between the client and the server. It provides a very reliable way for Sheriff and an application to verify that the other is a legitimate party.

4. Anti-tampering Measures

Comprehensive anti-tampering facilities are built into Sheriff, including:

  1. System clock verification: If a licence is time metered or expiry date controlled, Sheriff has built-in measures to prevent the manipulation of the system clock being used to gain extra time (E.g. extra days cannot be gained if the clock is wound back).
  2. If a licence is time metered or unit metered, Sheriff has built-in measures to prevent the licence from being backed up and restored in order to gain extra time or units.
  3. Hardware parameters cannot be emulated to duplicate licence for unauthorised machines.

5. Anti-debug Measures

Built-in anti-debug facilities prevent Sheriff codes from being traced and dissected.

6. Protected Licence Key Generator with Secret Codes

The Sheriff Licence Key Generator cannot be used to generate unauthorised Licence Keys. To generate Licence Keys for a product, a set of Secret Codes is required and each product has its own set of Secret Codes.