Authentication Methods
Several authentication methods are supported with IPsec virtual private
networks (VPN):
■ Username and password
■ A one-time password
■ Biometric features, such as fingerprint
■ Preshared key values
■ Digital certificates
Encryption Methods
IPsec encryption uses key values to encrypt and decrypt data. Keys can be
either symmetric or asymmetric. Symmetric keys use the same value to both
encrypt and decrypt the data. These include DES, 3DES, and AES. Asymmetric
keys use one value to encrypt the data and another one to decrypt it. Diffie-
Hellman and RSA use asymmetric keys.
Note
RSA is not an acronym—it is the initials of the last names of the algorithm’s inventors: Ron
Rivest, Adi Shamir, and Len Adleman