“PGP is a program developped by Phil R. Zimmermann that
allows you to communicate in a secure way over an insecure channel.
Using PGP you can easily and securely protect the privacy of your
data by encrypting them so that only intended individuals can read
it. PGP is based on public key cryptography: two complementary
keys, called a key pair, are used to maintain secure
communications. One of the keys is designated as a private key to
which only you have access and the other is a public key which you
freely exchange with other PGP users. Both your private and your
public keys are stored in keyring files.”
“In order to use PGP features, the first operation you must
accomplish is generating a key pair. … The generated key pair is
placed on your public and secret keyrings in your $HOME/.pgp
directory. Here you can find the file pubring.skr, containing the
public keys and the file secring.skr, the file of your secret
key.”
“A useful option of the the mailer Pine makes possible to handle
automatically the encryption of outgoing messages and the
decryption of the received ones. In the file $HOME/.pinerc search
for the lines starting with display-filters and sending-filters and
do the following insertions:
# This variable takes a list of programs that message text is piped into
# after MIME decoding, prior to display.
display-filters=_BEGINNING("-----BEGIN PGP MESSAGE-----")_ /usr/bin/pgpv
# This defines a program that message text is piped into before MIME
# encoding, prior to sending
sending-filters=/usr/bin/pgpe -taf _RECIPIENTS_
The display-filters line says that: “when a received mail starts
with the given string (i.e. —–BEGIN PGP MESSAGE—–) process
its contents using the program /usr/bin/pgpv”. Since all PGP
messages start in such a way all PGP encrypted messages are
automatically trapped by pgpv and decrypted (obviously only if they
are encrypted with your public key).”