Hello all,
Hoping someone can help me out here. I've burned almost a week trying to figure out how to decrypt an image file that has been encrypted using Blowfish CBC.
I found some code on the net and have modified as follows:
require 'openssl' require 'digest/sha1' ivArr = [0x0D, 0x0E, 0x0A, 0x0D, 0x0F, 0x0A, 0x0C, 0x0E ] iv = ivArr.pack("cccccccc") bf = OpenSSL::Cipher::Cipher.new("BF-CBC") key = Digest::SHA1.hexdigest("fOyBtMaN4u2T") bf.decrypt bf.key = key bf.iv = iv File.open("C:\\mapcrypt\\MAP.TIFF",'wb') do |enc| File.open("C:\\mapcrypt\\EncryptedMAP.TIFF","rb") do |f| size = File.size("C:\\mapcrypt\\EncryptedMAP.TIFF") blocks = size / 8
for i in 1..blocks r = f.read(8) cipher = bf.update(r) enc << cipher end
if size%8 >0 r = f.read((size%8)) cipher = bf.update(r) enc << cipher end end enc << bf.final end
However, this returns the error: OpenSSL::CipherError: wrong final block length from (irb):89:in `final' from (irb):89 from (irb):72:in `open' from (irb):72
I've also tried using the Blowfish library: require 'crypt/blowfish' blowfish = Crypt::Blowfish.new("fOyBtMaN4u2T") blowfish.decrypt_file('C:\\mapcrypt\\11225035.00X', 'MAP.TIFF') But this returns the error: NoMethodError: undefined method `%' for true:TrueClass from c:/ruby/lib/ruby/gems/1.8/gems/crypt-1.1.4/./crypt/ blowfish.rb:84:in `decrypt_pair' from c:/ruby/lib/ruby/gems/1.8/gems/crypt-1.1.4/./crypt/ blowfish.rb:82:in `downto' from c:/ruby/lib/ruby/gems/1.8/gems/crypt-1.1.4/./crypt/ blowfish.rb:82:in `decrypt_pair' from c:/ruby/lib/ruby/gems/1.8/gems/crypt-1.1.4/./crypt/ blowfish.rb:104:in `decrypt_block' from c:/ruby/lib/ruby/gems/1.8/gems/crypt-1.1.4/./crypt/cbc.rb: 62:in `decrypt_stream' from c:/ruby/lib/ruby/gems/1.8/gems/crypt-1.1.4/./crypt/cbc.rb: 99:in `decrypt_file' from (irb):93
I'm using ruby 1.8.6 (2007-09-24 patchlevel 111) [i386-mswin32]
Thanks in advance for your help,
Allen akt@frikshun.com
