#!/bin/bash
#
# This script demonstrates ascii armoring.  It is rather complicated
# because it uses the ascii armoring present in gpg, which wraps in
# a way that is unusable for irc.  One of the things that can be
# done is to join all the cyphertext lines together, and reformat
# them into a valid gpg message again at the other end.
#
# Decryption is a little tricky.  What we do is create a token ascii
# armored gpg message, strip it of the message content, fill it in
# with the reformatted message and pipe it back into gpg for
# decryption.
#
# Since the plaintext and cyphertext are read in non-newline binary
# mode, echo -n is used.

function encrypt {
	( echo "$KEY" ; cat ) | gpg -ca -z 9 --batch --passphrase-fd 0 | (
		while read && [ -n "$REPLY" ] ; do : ; done
		while read && [ -n "$REPLY" ] ; do
			[ -n "$LAST" ] && echo -n "$LAST " ;
			LAST="$REPLY"
		done
	)
}

function decrypt {
	read -a input
	( echo x | gpg -ca --batch --passphrase-fd 0 | (
		while read && [ -n "$REPLY" ] ; do echo "$REPLY" ; done
		while read && [ -n "$REPLY" ] ; do LAST="$REPLY" ; done
		echo
		for foo in "${input[@]}" ; do echo "$foo" ; done
		echo "$LAST"
	) ) | ( echo "$KEY" ; cat ) | gpg -a --batch --passphrase-fd 0
}

proto="$1"
shift 1

read KEY TRASH

case "$proto" in
encrypt) encrypt "$@" ;;
decrypt) decrypt "$@" ;;
*)	echo `basename $0` "{encrypt|decrypt} < text" 1>&2 ;;
esac