This may be a question better suited for a ruby mailing list.
On Jun 6, 2008, at 8:24 AM, FrikShun wrote:
>
> 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
> [EMAIL PROTECTED]
>
> >
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