Bitcoin zero knowledge cloud
The company is not able to access data stored on its servers, as all files are encrypted. Adding Bitcoin payments to this level of privacy provides Sync. There is a significant awareness and demand for data privacy protection, especially since Edward Snowden showed the world what governments are doing without the knowledge of the public.
As it should be for any business storing sensitive customer information in the cloud. And while we continue to offer traditional forms of payment such as credit card, Bitcoin is a win for our customers and a win for privacy in general.
Despite platforms such as Dropbox and Google Drive becoming ever-so-popular, all of these services lack the proper consumer privacy protection technology. In fact, the exact opposite is taking place; as these companies can harvest and sell consumer data to interested third parties. To make matters even worse, uploaded and stored files are encrypted, but in a far less advanced manner compared to Sync.
It will be interesting to see how many customers decide to sign up for a Sync. Blockchain technology could prove to be a stiff competitor for services like Sync and Dropbox, as it can offer decentralized encrypted cloud storage and file sharing. Only time will tell if such a service will see the light of day, though. So the buyer initially wanted to buy an input for his program, but now he would be just as happy to buy the preimage of a hash. As it turns out, Bitcoin already provides a way to sell hash preimages in a secure manner.
The effect of this payment is that the seller can collect it if he provides the hash preimage of Y and a signature with his key. As a result, when the seller collects his payment he is forced to reveal the information that the buyer needs in order to decrypt the answer. This ScriptPubkey is also the same as would be used for a cross-chain atomic swap or a lightning payment channel.
Wallet support for these transactions has been implemented for Bitcoin Core in PR This wallet support is used by the sudoku ZKCP client and server available at https: There are two primary restrictions of this approach. First, that it is interactive: And second, that the ZKP system, while fast enough to be practical, is still not very fast.
For example, in our demo the ZKP system proves 5 executions of SHA and the Sudoku constraints, and takes about 20 seconds to execute on a laptop. The verification of the proof takes only a few milliseconds. In Paypub, instead of using a zero-knowledge proof the buyer is shown a random subset of the data they are attempting to buy, and the seller is forced to unlock the rest when they collect their payment. Paypub avoids the complexity of dealing with a zero-knowledge proof— and also allowing the exchange of information that only humans can verify—, but at the cost of some vulnerability to cheating, and only being usable with a relatively large set of randomly verifiable information.
I look forward to the exciting applications people will find for them as the technology becomes increasingly practical. The first successful Zero-Knowledge Contingent Payment. The transfer involved two transactions: See the slides from the live demo. Background I first proposed the ZKCP protocol in in an article on the Bitcoin Wiki as an example of how tremendously powerful the existing primitives in Bitcoin Script already were.
The seller picks a random encryption key and encrypts the information the buyer wishes to buy. Using the ZKP system, the seller proves a composite statement: Y is the sha hash of the decryption key for Ex.