Schneier on Security

Here's a story that I read:


"Talking to Vula" is the story of a 1980s secret communications channel between black South African leaders and others living in exile in the UK. The system used encrypted text encoded into DTMF "touch tones" and transmitted from pay phones.


via Pocket https://www.schneier.com/blog/archives/2013/12/operation_vula.html