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Versions: 12
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Contents
# frozen_string_literal: true
module Firebug
require 'digest'
require 'securerandom'
require 'mcrypt'
class Crypto
# @param [String] key
def initialize(key)
@key = Digest::MD5.hexdigest(key)
end
# @param [String] data
# @return [String]
def encrypt(data)
# Create a random 32 byte string to act as the initialization vector.
iv = SecureRandom.random_bytes(32)
# CodeIgniter pads the data with zeros
cipher = Mcrypt.new(:rijndael_256, :cbc, @key, iv, :zeros)
add_noise(iv + cipher.encrypt(data))
end
# @param [String] data
# @return [String]
def decrypt(data)
data = remove_noise(data)
# The first 32 bytes of the data is the original IV
iv = data[0..31]
cipher = Mcrypt.new(:rijndael_256, :cbc, @key, iv, :zeros)
cipher.decrypt(data[32..-1])
end
# CodeIgniter adds "noise" to the results of the encryption by adding the ordinal value of each character with a
# value in the key. The plaintext key is hashed with MD5 then SHA1.
#
# @param [String] data
def add_noise(data)
noise(data, :+)
end
# The "noise" is removed by subtracting the ordinals.
#
# @param [String] data
# @return [String]
def remove_noise(data)
noise(data, :-)
end
private
# @param [String] data
# @param [Symbol] operator
# @return [String]
def noise(data, operator)
key = Digest::SHA1.hexdigest(@key)
Array.new(data.size) { |i| (data[i].ord.send(operator, key[i % key.size].ord) % 256).chr }.join
end
end
end
Version data entries
12 entries across 12 versions & 1 rubygems