People with a poor understanding of crypto, generally the types of people who have NIH syndrome will reinvent cryptography. I've personally worked with NIH SSL

People with a poor understanding of crypto, generally the types of people who have NIH syndrome will reinvent cryptography. I've personally worked with NIH SSL systems based on the idea of XOR'ing the messages with the 3rd byte of a header field called 'CryptoKey' or something like that. There are all sorts of homebrew crypto systems out there in the wild, if you're lucky it's based on an actual algorithm, but mostly it's worst than an enigma machine. In the case of the system I was working with the 3rd byte of the message was always a : so I ditched the whole look at the header thing, and just XOR'd the 3rd byte with : to derived the 'key'.