The algorithm itself looks pretty strong for time but weaker than DES having a 16 byte non-linear function in a cipher feedback loop without chaining. Due to th

The algorithm itself looks pretty strong for time but weaker than DES having a 16 byte non-linear function in a cipher feedback loop without chaining. Due to the way the registers aren't randomised and the key is entered it leaks plain-text quite badly. The story here is that Stefan Marsiske studied the algorithm and wrote a cracker that can break a PX-1000Cr message in 4 seconds on a modern laptop, with just 17 characters of cipher-text. Some of the story speculates on the effect this backdoor may have had on anti-apartheid in the 80s and an anecdotal conclusion that a developer had tipped-off the movement about weakened cryptography and helped them revert to a secure version of the PX-1000.