fairCASH - the first true digital cash solution

Due to the Digital Coin concept, a value transfer between payer and payee is realized by transferring ownership of the eCoin. An essential part is the way how this transfer is conducted: Following the cash paradigm, it needs to be done peer-to-peer and offline in a repeatable way. Such a transfer is called teleportation.

It is a method of transportation in which information is encoded, usually instantaneously, at one point, transmitted at the speed of light (or a little bit slower), so that the digital object could be recreated at the destination point. Etymology: the word was coined joining the Greek prefix tele- (meaning ‘distant’) to the Latin verb portare (meaning 'to carry').


Four steps in our teleportation of secrets (here eCoins).
Four steps in our teleportation of secrets (here eCoins).

Teleportation within our fairCASH system is kind of a multipurpose generic two-party protocol for exchanging digital secrets. Such a thing is useful for applications like signature transfers, or cryptographic key exchanges, sending certified eMail, handling CO2 soiling certificates, building Digital Cash based payment systems, running a digital content (multimedia) distribution, guarding medical records, implementing licensing control, and others. It gets done by a sequence of exchanges, classified as “fair exchange protocol”. However, it is often interesting to tailor protocols for each of these specific problems, allowing more efficient solutions including features specific to a given problem. All these types of protocols play an important role in mCommerce where participants require mutual guarantees like non-repudiation.

Our method is moving protected immaterial secrets peer-to-peer between two logical interlinked nano-safes through a VPN/VPC in a non-repudiational way. Our shown figure depicts a symbolic teleportation process:

'Secret id5' is prepared within the first step to the transmission channel and transmitted from nano-safe (b) through the usage of a VPN/VPC in steps two and three. After receiving the secret in the last step four, the secret is deposited in nano-safe (a). With such a successful transfer the original owner of the secrets (here nano-safe (b)) loses his ownership sentential and irrevocably. In return, he receives a (not shown) signed receipt from the receiver, in our example nano-safe (a). Proposing our protocol tightly coupled to a Hardware-Security-Module (HSM)-centric tamper-resistant hardware covers the complete embedded logic part to act as exchange engine for ICT secrets. It will allow their safe movement between two protected endpoints. It belongs to the type-class of fair exchange protocols, ensuring that even if one of the communicating parties behaves unfairly, neither will gain anything from the transaction.