TAU is an electronic currency that aims to promote essential financial behavior and increase economic circulation. We introduce a new consensus mechanism, Proofof-transaction (POT), that is fair, secure and environmentally friendly. POT uses on-chain accumulated transaction fee as proof to generate new blocks. The reward is transaction fees contained in each block. Participants can form groups called mining club, which distributes block reward to all club members through an efficient club wiring transaction. Under POT, network security is maintained collectively by users’ transactions.