5

I have a key.bin file which content is something along the lines of:

-12, 110, 93, 14, -48, ...

This is being used by a service to decrypt 3DES content, but I need to encrypt it via Ruby.

I've tried loads of scenarios with how to set the key and what to do with it, but to no avail as of yet:

  • Tried splitting the key by , and converting each number to hex, concatenating the hex values to make the key
  • Tried converting the number string to binary
  • Tried converting the resulting hex to binary

I assume what I need to do is something simple like:

des = OpenSSL::Cipher::Cipher.new('des3')
des.decrypt
des.key = mistery # this step is where i'm having problems at
final = des.update(encrypted) + des.final

Any ideas on what I should do with this key?

Key sample:

-62,-53,124,-110,37,-88,-48,31,-57,93,70,-101,44,69,-88,-57,-123,-99,118,-119,110,55,11,14

Data sample:
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=
changelog
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    Can you feed it an arbitrary key.bin for us? If so, some sample input, output, and key would go a long way toward reverse engineering this problem. Alternately, what is the web service in question? – SilverbackNet Dec 14 '10 at 06:56
  • 1
    The key is a byte string, each number representing 8 bits (e.g. 124 is 01111100. It's probably using two's compliment. You'll have to concatenate the bytes, but you'll have to test the endianness. – moinudin Dec 23 '10 at 15:01

1 Answers1

5

Got it working!

Here's how:

Decryption

def read_key(key_file)
  File.read(key_file).split(',').map { |x| x.to_i }.pack('c*')
end
des = OpenSSL::Cipher::Cipher.new('des-ede3')
des.decrypt
des.key = read_key('key.bin')

result = des.update(decoded) + des.final

Encryption

def read_key(key_file)
  File.read(key_file).split(',').map { |x| x.to_i }.pack('c*')
end
des2 = OpenSSL::Cipher::Cipher.new('des-ede3')
des2.encrypt
des2.key = read_key('key.bin')

result = des2.update(result) + des2.final
puts Base64.encode64(result)
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