#!/bin/bash
# Argument 1 = source PGP symmetric key file (containing an encrypted PGP SYMMETRIC message)
# Argument 2 = filename base for the PGP key
#		Ex: "PGP_INTRO_EXAMPLE" will create that file in crackmes, find its hash and create another file with the same name, but .hash type.

# Change pwd to dir of the script.
cd "${0%/*}"

if [ -z $1 ]
then
	echo "Invalid arguments. Please use the '--help' flag for more information."
	exit
elif [ -z $1 ] && [ -z $2 ]
then
	echo "Invalid arguments. Please use the '--help' flag for more information."
	exit
elif [ $1 = --help ] || [$1 = '--h' ]
then
	echo "Use this tool to quickly decrypt a PGP symmetric message, using a standard English dictionary/Rainbow Table."
	printf "\n"
	echo "ARGUMENTS: "
	echo "\$1 = source PGP symmetric message file."
	echo "\$2 = filename base for the created key information."
	echo "        This file is also used to access JTR's stored password information."
	echo "        Output info from JTR is stored in '$PWD/crackmes/\$2.output'"
	exit
fi

if ! [ -r $1 ]
then
	echo "File '$1' does not exist or cannot be read by bash."
	exit
fi

# Everything appears to be in good order. Get started.
echo "PGP source file: '$1'"
echo "PGP destination file: '$PWD/crackmes/$2.hash'"
echo "**Output information storage: '$PWD/crackmes/$2.output'"
DSP_OUTPUT="$PWD/crackmes/$2.output"
touch $DSP_OUTPUT

# Output the PGP hash of the file.
./run/gpg2john $1 >"crackmes/$2.hash"

# Run the crack with the wordsEn.txt rainbow table.
echo "Running JTR cracking utility."
echo "Wordlist is rainbow table: '$PWD/wordsEn.txt'"
./run/john --wordlist="$PWD/wordsEn.txt" --rules "crackmes/$2.hash"

# Make sure JTR exited cleanly.
if ! [ $? -eq 0 ]
then
	printf "\nThere was an issue with JTR. Please check your logs or reinstall the program.\n"
	exit
fi

# Store the password. This method is likely over-complicating things and can be refined later.
DSP_PASS=`./run/john --show "crackmes/$2.hash" | sed -n '/:[a-zA-Z0-9]/p' | grep -o "[a-zA-Z0-9]*$"`

if [ -z $DSP_PASS ]
then
	echo "JTR did not manage to extract a user:password keypair :("
	exit
fi

echo "Password of the key:" >$DSP_OUTPUT
printf "$DSP_PASS\n\n" >>$DSP_OUTPUT
echo "DECRYPTED MESSAGE:" >>$DSP_OUTPUT

# Decrypt the message file and output it into the output file.
printf "$DSP_PASS" | gpg -d --passphrase-fd 0 "$1" | tee -a $DSP_OUTPUT
printf "\n\n" >>$DSP_OUTPUT