So there's a slight world divide in digital payments with bitcoin using ECDSA and GPG, payswarm / webid etc using largely RSA
Here's how to bring the two worlds together and enable bitcoins be sent over webid or payswarm
Problem: Alice and Bob have RSA key pairs, but no public bitcoin addresses. Alice wants to send 1 BTC to Bob.
1. Alice takes Bob's WebID and encrpyts it with her private key (to create entropy) ...
2. Alice uses that message as the seed to produce btc address (as per
http://brainwallet.org ) with ECDSA key pair
3. Alice sends coins to this address
4. Alice and then encrypts the seed again with Bob's public key
5. Bob decrypts the seed using his private key
6. Bob can now use the seed to recreate the wallet and spend the coins
Unless I've made an error, I believe this unites the web paradigm and crypto currency paradigm into one potentially giant eco system ...