Crunchfish Digital Cash Wallet is an extremely flexible and interoperable solution that compliments any payment service, on any payment scheme, with capabilities that replicate paying with cash. A two-step hierarchical architecture makes Digital Cash payments independent from the net, offering instant clearing offline at the moment of payment, followed by settlement online to move money between accounts. On request by the payer, payments may be private in relation to banks, within the limits of money laundering regulations.

The Digital Cash Wallet has a mirrored Digital Cash Account which is used for settlement online, when either the payer or the receiver connects online, independently of each other. The Digital Cash Account account may only be debited from the Digital Cash Wallet protecting against double spending and overdrafts. It registers all activity in the Digital Cash Wallet.

Digital Cash payments are debited against a balance maintained by the Digital Cash Wallet, which may be implemented using signed risk parameters or as a trusted application running on a smart card or a digital wallet, on either a smartphone or a feature phone. It functions like a tollgate securing that sufficient balance is available and that issuer rules are fulfilled, before a cryptographically signed Digital Cash payment is generated. The payments are assigned and transferred to the receiver using proximity interaction, who may verify them on an electronic device in offline mode.

Crunchfish is global Certificate Authority for the Digital Cash Wallet. It is globally interoperable cross-service and cross-scheme by the use of signed user and Digital Cash certificates. It is also cross-border by the use of a foreign exchange table in the payment app.