I wouldn't say trivial, even if you know how the system works, it can take a lot of time to break things. A good example would be Enigma. There is the BOINC bas

I wouldn't say trivial, even if you know how the system works, it can take a lot of time to break things. A good example would be Enigma. There is the BOINC based project Enigma@Home [1], which tries to decypher intercepted messages. Over 74880 CPU-years have been spent to crack messages, and there are still some unbroken. And do not forget the Voynich manuscript [2], from the 15th century, which still remains un-decyphered. [1]: http://www.enigmaathome.net/ http://www.enigmaathome.net/ [2]: https://en.wikipedia.org/wiki/Voynich_manuscript https://en.wikipedia.org/wiki/Voynich_manuscript