One time pad ciphers in emails
In order to achieve very high security for privacy, would it be cryptographically secure to use one time pad ciphers in emails?


OTP offers perfect secrecy, so if it's feasible to use it, it is secure.

However, OTP alone offers no authentication and leaves the message malleable. If Alice sends a message Y to Bob, standing for 'yes', Mallory can guess this and modify the message to say N instead (but he would garble the message if he thought it said something different).

You would need to add a MAC to get authentication as well.