I was going through the protocols that are used in email applications (specifically POP and APOP) and I happened to come across this answer somewhere. It says
Short for Authenticated Post Office Protocol, it is similar to the POP protocol except that APOP enables your password to be encrypted while being transmitted over the network. Using POP mail, when you authenticate your username and password in your e-mail client, your password is sent over the network in plain text. If your e-mail client uses APOP, then the password is encrypted while being transmitted. APOP prevents hackers from seeing your password information with sniffer programs.
My question is :Is that the major difference between APOP and POP? Is the password not encrypted when POP protocol is used? If not, will it not cause security concerns?