publickeytoken

Public key tokens are cryptographic hashes used to identify a piece of code, such as a compiled assembly. A public key token is used to reference the public key in an assembly, so that code can communicate with the correct version of the assembly, as well as prevent tampering.
Public key tokens are created by hash algorithms, usually SHA-1. Once the token is created, it is encoded in several formats, such as Base64, with each format having its own standard length.
Public key tokens are essential to ensuring reliability, safety and security in the software development process. For example, if a company is releasing an application that depends on an assembly, the application’s installer will check the public key token of the assembly and will only install if the token matches the one provided by the developer. If the tokens do not match, then the application won't install.
In short, public key tokens are secure, reliable and critical to the software development process. They are used to reference the public key in an assembly and provide that extra level of security to ensure safe communication between applications and assemblies.