Encrypting history?

[Lloyd Zusman <ljz@xxxxxxxxxx>]

I would like my command history to be stored in an encrypted file. I
have read a few messages in this list from 2007 which state that there
isn't a straightforward way to do this within zsh, itself, and the use
of an encrypted file system is suggested.

However, I think that there might indeed be a way to accomplish this.

Is it possible to do the following?

Make sure that SAVEHIST is set to 0.

Then, on login, prompt the user for a password. Remember this password
for the duration of the shell session. Then, use this password along
with a decryption program to read an encrypted history file called, for
example, ~/.ehistory. Put the decrypted contents of this file into the
current shell's history list via the repeated use of the "print -s"
command.

Finally, on logout, pipe the output of "fc -ln 1" through a program
which uses the same password entered at login time to encrypt the
history and write it to the ~/.ehistory file.

Can any of you see any reason for why this would not work?

Or alternatively, is there perhaps a better way to do this within zsh?

Thanks in advance.
  

-- 
 Lloyd Zusman
 ljz@xxxxxxxxxx
 God bless you.