#Bitcoin  =

{

Ecash : David Chaum 1982,

E-gold : Douglas Jackson and Barry Downey 1996,

Hashcash : Adam Back 1997,

Bit gold : Nick Szabo 1998,

B-money : Wei Dai 1998,

Reusable Proofs of Work : Hal Finney 2004,

Difficulty Adjustment: S.Nakamoto,

}