Blockchain and the cryptography of the future.

What approach or approaches will characterize the cryptography of the future?

From my point of view, the answer is not yet clear, but rather still in the process of development. The question should be taken as a starting point from which to begin thinking that “in the future,” in addition to advanced mathematics, contributions may also come from other disciplines such as quantum physics.

In recent years, there have been various debates and scientific disclosures about quantum computing and related computers, to the point that not only computer giants but also groups of states have invested in this context.

In 2018, Europe allocated €1 billion over 10 years (Link “Sole 24 ore” of 30.10.2018) to study much more powerful computers than those currently in use and new generation cryptographic systems.

“Quantum Flagship”: the European initiative

Launched in Vienna, it is headed by Professor Tommaso Calarco and also saw the CNR (National Research Council) as a key element in its launch.

The role of the CNR here is very interesting: as a member of the project’s governance structure, it has the valuable task of being a source of preparation for new researchers, with the goal of reaching industrial laboratories starting from pure research ones.

All this is tangible proof of Italy’s commitment to an ambitious project at the European level.

In my opinion, events like the one just described are an additional source of attention and fundamental focus to be brought to the study of the path that quantum cryptography is opening up.

It is interesting to note that 1970 is a date as important as it is distant for quantum studies: a group of scientists led by Stephen Wiesner devised a protocol for the realization of quantum banknotes during this period.

This study was taken up several years later by Bennett and Brassard, who devised a protocol for generating and exchanging information securely using secret keys and elementary particles, exploiting the laws of quantum mechanics.

QKD – Quantum Key Distribution

Hence the idea of “Quantum Cryptography” (QKD – Quantum Key Distribution) which aims to provide new models of secret key generation and distribution.

A QKD system has prerequisites, namely the existence of the following communication channels:

1. Quantum: where the exchange of elementary particles takes place. To date, there are two quantum channels: optical fibers and free space;
2. Classic: on which the interacting parties guarantee the confidentiality, integrity, and authenticity of the transferred information.

In particular, the quantum channel ensures that two interlocutors share a random key without it being compromised, because otherwise the channel itself would signal the anomaly to the two interlocutors.

Therefore, according to this principle of operation, once the two interlocutors have achieved the correct sharing of a “token,” they can use it to encrypt their messages and then send them over any insecure channel.

In fact, the use of QKD for transfer and 2FA (Two Factor Authentication) for the processing of an encryption code results in a communication system that is absolutely secure.

• What would happen if the same principle were applied in the processing of a transaction within a blockchain context?
• What changes would affect the logical models with which the current major market blockchains operate?
• Will it still be necessary to perform mathematical algorithms deterministically in order to establish the convergence of a result?

Evolutionary insights

Nodes will probably be connected to each other through QKD channels, perhaps via an urban fiber. A protocol will be redefined to add new blocks that are radically different from those known so far.

Rather than focusing on the development of new blocks in “mining” nodes, all nodes will be able to agree on a new block on equal terms.

In addition, significant advances in the theory and practice of quantum communications (e.g. earth-satellite and quantum repeaters) could open the door to the development of a public QKD worldwide (quantum internet) where each party can authenticate themselves anonymously using their own “encryption key” and at the same time securely certify the content of their messages with classical tools.

That is why healthy cryptographic-technological debates like the current one can be a fertile ground where multiple disciplines can and will interact and interoperate to give rise to new forms of cryptography or evolutionary developments of cryptographic forms known to date.