1. Optimistic fair exchange of digital signatures;Asokan,1998
2. Optimistic protocols for fair exchange;Asokan,1997
3. Efficient verifiable encryption and fair exchange of digital signatures;Ateniese,1999
4. Stateless-recipient certified e-mail system based on verifiable encryption;Ateniese,2002
5. Off-line fair payment protocol using convertible signatures;Boyd,1998