What is PAP?
Password authentication protocol (PAP) and challenge handshake authentication protocol (CHAP) are both used to authenticate PPP sessions and can be used with many VPNs. Basically, PAP works like a standard login procedure; the remote system authenticates itself to the using a static user name and password combination. The password can be encrypted for additional security, but PAP is subject to numerous attacks. In particular, since the information is static, it is subject to password guessing as well as snooping.
