Abstract: A proof of wallet approach is used for transaction validation for a digital currency. When a transaction is requested, a set of witness nodes are selected to form an ad hoc neural network. The witness nodes may be client devices of other users of the digital currency. Each witness node receives input information about the transaction (e.g., an encrypted amount and nonce) and neural network parameters (e.g., input weights and a bias). The input information passes through the ad hoc neural network, which generates an output validation value. The transaction is approved if the output validation value is consistent with a verification value generated from the transaction parameters, neural network parameters, and digital currency information stored on a blockchain.