Project Eleven has unveiled an early security prototype for the Bitcoin network. The mechanism uses zero-disclosure evidence. This will help wallet owners to confirm control over the funds. The problem is urgent due to the threat of the emergence of powerful quantum computers. In the future, they will be able to restore the private key to an open address. Experts call this moment "Q day". Then the attacker and the real owner will be able to create the same signatures. The proposed scheme solves this problem elegantly and reliably. The user proves control over more than just the current key. It also confirms the knowledge of an earlier key in the structure. At the same time, the parental secret itself remains completely hidden from outsiders.

The mechanism relies on a secure stage of derivation in hierarchical wallets. The child key is created using the private parent key. The HMAC-SHA512 cryptographic algorithm is used for this purpose. A quantum computer will be able to obtain the address key from a public one. However, he will not be able to recover the parent key through this stage. Grover's algorithm reduces the complexity of iterating over hash functions. But it does not make such an operation feasible in practice. The developers have already published the source code on the GitHub platform. The approach is based on the method of transferring the signature to a post-quantum scheme. According to internal tests, generating proof on a modern laptop takes a fraction of a second. Checking the finished file takes only about forty milliseconds. Currently, the prototype supports three main types of bitcoin addresses.

For the mechanism to work properly, changes to the network rules will be required. The Protocol must separately recognize such evidence and allow its use. This will allow funds to be transferred to new post-quantum addresses. The scheme is designed for users who will not be able to transfer funds on time. It complements other suggestions for creating new types of addresses. For example, recently the BIP-360 proposal received the official draft status. It describes a new type of Pay-to-Merkle-Root output. The transaction must pass through a script tree with post-quantum conditions. The Quantum Advisory Council assessed the risks for millions of bitcoins. Old exits with exposed public keys are under threat. The community will have to decide how to handle the competing demands of the owner and the attacker. Reaching consensus on updating the protocol remains a difficult task.