Principle of OTR protocol Diffie–Hellman (DH) key exchange Diffie–Hellman key exchange is performed between integers and a finite cyclic group. Started here, integers are represented with lowercase letters, while elements of the cyclic group are represented with uppercase letters, and “==” is used to represent mathematical identity. Character of finite cyclic groups The number of the elements of a finite cyclic group is finite (as its name), and is called the order of the group.
