100 lines
1.9 KiB
Ruby
100 lines
1.9 KiB
Ruby
module Zip
|
|
module TraditionalEncryption
|
|
def initialize(password)
|
|
@password = password
|
|
reset_keys!
|
|
end
|
|
|
|
def header_bytesize
|
|
12
|
|
end
|
|
|
|
def gp_flags
|
|
0x0001 | 0x0008
|
|
end
|
|
|
|
protected
|
|
|
|
def reset_keys!
|
|
@key0 = 0x12345678
|
|
@key1 = 0x23456789
|
|
@key2 = 0x34567890
|
|
@password.each_byte do |byte|
|
|
update_keys(byte.chr)
|
|
end
|
|
end
|
|
|
|
def update_keys(n)
|
|
@key0 = ~Zlib.crc32(n, ~@key0)
|
|
@key1 = ((@key1 + (@key0 & 0xff)) * 134_775_813 + 1) & 0xffffffff
|
|
@key2 = ~Zlib.crc32((@key1 >> 24).chr, ~@key2)
|
|
end
|
|
|
|
def decrypt_byte
|
|
temp = (@key2 & 0xffff) | 2
|
|
((temp * (temp ^ 1)) >> 8) & 0xff
|
|
end
|
|
end
|
|
|
|
class TraditionalEncrypter < Encrypter
|
|
include TraditionalEncryption
|
|
|
|
def header(mtime)
|
|
[].tap do |header|
|
|
(header_bytesize - 2).times do
|
|
header << Random.rand(0..255)
|
|
end
|
|
header << (mtime.to_binary_dos_time & 0xff)
|
|
header << (mtime.to_binary_dos_time >> 8)
|
|
end.map { |x| encode x }.pack('C*')
|
|
end
|
|
|
|
def encrypt(data)
|
|
data.unpack('C*').map { |x| encode x }.pack('C*')
|
|
end
|
|
|
|
def data_descriptor(crc32, compressed_size, uncomprssed_size)
|
|
[0x08074b50, crc32, compressed_size, uncomprssed_size].pack('VVVV')
|
|
end
|
|
|
|
def reset!
|
|
reset_keys!
|
|
end
|
|
|
|
private
|
|
|
|
def encode(n)
|
|
t = decrypt_byte
|
|
update_keys(n.chr)
|
|
t ^ n
|
|
end
|
|
end
|
|
|
|
class TraditionalDecrypter < Decrypter
|
|
include TraditionalEncryption
|
|
|
|
def decrypt(data)
|
|
data.unpack('C*').map { |x| decode x }.pack('C*')
|
|
end
|
|
|
|
def reset!(header)
|
|
reset_keys!
|
|
header.each_byte do |x|
|
|
decode x
|
|
end
|
|
end
|
|
|
|
private
|
|
|
|
def decode(n)
|
|
n ^= decrypt_byte
|
|
update_keys(n.chr)
|
|
n
|
|
end
|
|
end
|
|
end
|
|
|
|
# Copyright (C) 2002, 2003 Thomas Sondergaard
|
|
# rubyzip is free software; you can redistribute it and/or
|
|
# modify it under the terms of the ruby license.
|