SSL VPN: SSL Tunnel Establishment
2. The router responds with a digital certificate which contains the public key that is digitally signed by Certificate Authority.
3. Host generates a shared-secret key and encrypts the key with the public key received from the router.
4. Host sends the shared-secret key to the router.
5. Router decrypts the shared-secret key with its private key.
6. Now the router and host got the symmetric key (the shared-secret key), and both will use this key to encrypt the SSL session.
SSL uses encryption algorithm with key lengths between 40 and 256 bits.