Cuban HF Number Stations

An article by Dirk Rijmenants describes how the seemingly secure HF encryption system used by Cuba was broken.

In recent years there have been convictions of a number of Cuban agents who had been receiving encrypted messages via shortwave radio, broadcast by Cuban Numbers Stations.

Read Cuban Agent Communications - Failure of a Perfect System
http://users.telenet.be/d.rijmenants/papers/
cuban_agent_communications.pdf

Dirk's Weblog - Cuban Number Stations
http://rijmenants.blogspot.com/2010/02/
cuban-agent-communications.html

Number Stations
http://users.telenet.be/d.rijmenants/en/numbers.htm

Cipher Machines and Cryptology
http://users.telenet.be/d.rijmenants/

Thanks to Mike Barraclough for spotting this item.