"Email is a rather insecure way of transporting information.
Virtually anybody can read the contents of your messages. Probably
the only way to prohibit this is to encrypt your email."
"PGP (Pretty Good Privacy) has always been a popular choice
for public key encryption. K Mail works fine with PGP. I tried a
combination of K Mail and PGP 5 on a Linux machine."
"Probably the only set-up you need to do is tell K Mail your PGP
identity. Do this on the PGP tab of the "Settings" dialog. My user
identity is "0x3D8270DE", for example."