(programming required) As we suggested, one-time pads are secure if they’re used only once, but using the same key more than once compromises security. I took a (famous) document written in English,...

(programming required) As we suggested, one-time pads are secure if they’re used only once, but using the same key more than once compromises security. I took a (famous) document written in English, and encoded it as follows: I converted each character to an ASCII value (in binary, 00000000 to 11111111), and separated this bitstring into 40-bit chunks. (Each chunk contains 5 characters, with 8 bits each.) I generated a 40-bit key, and encoded each chunk using that key. (That is: I used a one-time pad more than one time!) The encoded document starts like this

You can find the full encoding at http://cs.carleton.edu/faculty/dln/one-time-pad.txt. Figure out (a) what 40-bit key I used, and (b) what the encoded document is.