ios7crypt.rb

#!/usr/bin/env ruby
 
# Author:: Andrew Pennebaker
# Copyright:: Copyright 2007 Andrew Pennebaker
# License:: GPL
#
# == Synopsis
#
# ios7crypt: encrypts and decrypts passwords with Cisco IOS7 algorithm
#
# == Usage
#
# ios7crypt [OPTIONS]
#
# --help, -h:
#    show help
#
# --encrypt, -e <password1> <password2> <password3> ...:
#    prints out the encrypted passwords as hashes
#
# --decrypt, -d <hash1> <hash2> <hash3> ...:
#    prints out the decrypted hashes as passwords
 
require "getoptlong"
require "rdoc/usage"
 
$xlat=[
	0x64, 0x73, 0x66, 0x64, 0x3b, 0x6b, 0x66, 0x6f,
	0x41, 0x2c, 0x2e, 0x69, 0x79, 0x65, 0x77, 0x72,
	0x6b, 0x6c, 0x64, 0x4a, 0x4b, 0x44, 0x48, 0x53,
	0x55, 0x42, 0x73, 0x67, 0x76, 0x63, 0x61, 0x36,
	0x39, 0x38, 0x33, 0x34, 0x6e, 0x63, 0x78, 0x76,
	0x39, 0x38, 0x37, 0x33, 0x32, 0x35, 0x34, 0x6b,
	0x3b, 0x66, 0x67, 0x38, 0x37
]
 
def encrypt(password)
	seed=rand(16)
	password=password[0, 11]
 
	hash=(0 .. (password.length-1)).collect { |i| $xlat[(seed+i)%$xlat.length] ^ password[i] }
 
	return format("%02d", seed) + hash.collect { |e| format("%02x", e) }.join("")
end
 
def decrypt(hash)
	seed=hash[0, 2].to_i
 
	hash=hash[2, hash.length-1]
 
	pairs=(0 .. (hash.length/2-1)).collect { |i| hash[i*2, 2].to_i(16) }
 
	decrypted=(0 .. (pairs.length-1)).collect { |i| $xlat[(seed+i)%$xlat.length] ^ pairs[i] }
 
	return (decrypted.collect { |e| e.chr }).join("")
end
 
opts=GetoptLong.new(
	["--help", "-h", GetoptLong::NO_ARGUMENT],
	["--encrypt", "-e", GetoptLong::NO_ARGUMENT],
	["--decrypt", "-d", GetoptLong::NO_ARGUMENT]
)
 
mode = :help
 
opts.each do |option, value|
	case option
		when "--help"
			RDoc::usage
		when "--encrypt"
			mode = :encrypt
		when "--decrypt"
			mode = :decrypt
	end
end
 
case mode
	when :help
		RDoc::usage
	when :encrypt
		ARGV.each { |arg| puts encrypt(arg) }
	when :decrypt
		ARGV.each { |arg| puts decrypt(arg) }
end