Decryption of an 8-bit code

I'm trying to crack a code that's concatenated ascii codes, encrypted by xor'ing each ascii code with an 8 bit key. Decoding it is apparently an xor operation, however I've hit a brick wall.

My algorithm is 1) create a decrypt code 2) xor each letter with code 3) translate back to a number 4) change number to letter 5) print out message

3,4, and 5 a straightforward, but I can't move past 1 and 2

My code so far is

encrypted = '11111111111111111011101111100000000100000000101000101000000001000100010111101001001010111010100011100101';
  z = reshape(encrypted, length(encrypted)/8,8)
  key = dec2bin(0:255,8)

Basically I'm going to use brute force to crack it, and split things off into groups of 8.

If anyone has any suggestions I would really appreciate it!

Thank you

[Walter Roberson]

You probably want

z = reshape(encrypted .', 8, length(encrypted)/8).' ;

Answer 1

[Walter Roberson]

You cannot reliably break xor codes using brute force. You cannot, for example, determine whether the original source was

IBM

or

HAL

(as in 2001's HAL 9000 computer)