The defenders of anonymity on the internet

David Chaum also invented blind signatures[1], which as I understand it make truly anonymous electronic cash possible.

[1] http://en.wikipedia.org/wiki/Blind_signature

Yes, and Darkcoin uses ECC-based blind signatures. [1]

Lack of anonymity is a huge problem with Bitcoin at the moment, IMO. As soon as you transact with someone, they can see all past and future transactions associated with your address using blockchain forensics.

https://www.darkcoin.io/intro.html

For those in the UK, the accompanying Horizon episode is now online.

http://www.bbc.co.uk/iplayer/episode/b04grp09/

The 60 minute running time meant the programme had to skim the surface for some topics. Nevertheless, I thought the programme was well-made and informative. Recommended.

It's now on YouTube (watch it before it's gone)

https://www.youtube.com/watch?v=fTjNkbLBEqg

Look forward to watching this Horizon episode.