"a OTP doesn't stop a man-in-the-middle attack" This is true. " Once the attacker is on the remote system they can open a backdoor." If you're using OTP's, t

"a OTP doesn't stop a man-in-the-middle attack" This is true. " Once the attacker is on the remote system they can open a backdoor." If you're using OTP's, then there's really only one way an attacker could do that: hijack your session after you use the OTP to log-in, but before you have logged out. OTP's won't protect you from such a session hijack. However, they will protect you from a simple keylogger on the untrusted machine you're logging-in from, since recording the password you used to log-in will be useless for the attacker (as far as future logins are concerned). This is why OTP's are very, very important and useful for access from untrusted systems... particularly for uses such as reading your email through webmail interfaces while away at on a business trip or on vacation, where your only access to your email might be through an untrusted computer at an internet cafe or somesuch. "Sand boxing seems to be a good idea" I'm all for it. But that is a solution to a completely different problem: how to keep the rest of your system from being compromised further once someone has already hacked in to a part of your system. OTP's are a way to (hopefully) prevent that from even happening (by neutralizing the usefulness of a password that has been compromised on an untrusted machine).