Bumping Telephones for small Payments

Bump is an API and service that allows people to initiate a data transfer between their telephones by bumping them together. The service matches location, time and kinetics of the bump between the phones. Then contact data may be exchanged or, more interesting, small amounts of money my be sent.

The bump procedure ensures that users understand what's happening and privacy may be added by adding a PKI to the bump matching service: if the match is made, the service can send public keys of the bump partner.