Virtual private networks which help people to stay anonymous on public connection by acting as a proxy server use the following methods for the security and safety of the data.
The internet protocol security (IPsec) is a protocol that provides safe connection at the Internet network layer. It was introduced by the Internet Engineering Task Force for secure transmission of information through a network. IPsec design is in accordance with the security objective of authentication, integrity and confidentiality. In this security protocol the data is encrypted, encapsulated in an IPsec packet and at the end of the tunnel point the original IP packet decryption takes place after de-encapsulation on reaching the intended user. This has a limitation of sending only the IP packets. IPsec uses the authentication header and Encapsulated security payload (ESP) protocols for its security services.
Transport layer security (SSL/TLS)
This security protocol is capable of tunneling an entire network’s traffic and uses a TCP port. It can also secure an individual connection. This security protocol provides digital signature feature which is unique in itself. In the case of SSL/TLS cipher suites are used to define encrypted functions whereas in IPsec the two ends that are communicating have to agree to cryptographic function. An SSL server certificate is used to authenticate SSL VPN to the web user so that the users know that they are communicating with a server that is trustworthy while using the browser. The locations where the IPsec runs into trouble with network access translation the SSL VPN can be used.
PPTP (Point to Point tunneling protocol)
This method of security used by VPN providers has become obsolete now which used TCP port 1723 to run. It faced many security issues because of which it went out of use. The data is encapsulated in PPP packets allowing the tunneling of any protocol that can be carried in PPP like IP and IPX. PPTP uses a generic routing encapsulation tunnel along with TCP control channel for encapsulation.
Tunneling through layer (L2TP)
This security protocol that is used along with point to point protocol of Microsoft and L2F of Cisco. This security protocol can help to transfer non-IP related protocol on an IP network. It is most commonly used along with IPsec because of the lack of confidentiality provided by L2TP. When they run all L2TP data appear as one single encrypted packet to the IPsec system.