| Diffie-Hellman is a well-known method of sending symmetric keys over remote systems through the use and exchange of asymmetric, public keys. Routers A and B create public and private keys following the Diffie-Hellman requirements. Both routers exchange public keys. Each router takes its own private key and the other router's public key and inputs them into the Diffie-Hellman algorithm. The results are a symmetric key at each router that is equal to the other routers. This symmetric key is used for DES encryption.