This chapter introduces the concepts of cryptography and VPN technologies. It covers the following topics:
• Need for VPN and VPN deployment models
• Encryption, hashing, and digital signatures and how they provide confidentiality, integrity, and nonrepudiation
• Methods, algorithms, and purposes of symmetric encryption
• Use and purpose of hashes and digital signatures in providing integrity and nonrepudiation
• Use and purpose of asymmetric encryption and Public Key Infrastructure (PKI)
An IP Security (IPsec) virtual private network (VPN) is an integral part of the security architecture of most organizations. It is used to connect branch offices, remote employees, and business partners ...