The World is confronted with an unprecedented challenge to contain the spreading of Sars-CoV-2. As reported by Cointelegraph.com(1), The World Health Organisation just announced that they put in place a Blockchain to combat CoViD-19! How is it that Blockchain can help the WHO?
The global pandemic needs timely, accurate and comprehensive crisis management. The very basis for this work is information. Having A GLOBAL TRUSTED SINGLE SOURCE OF pandemic treatment-related data is crucial and can help to act in a life-saving way. Blockchain is the database protocol that realises this one single source of truth.
A Blockchain is a database, but not a traditional one. It is a database that has no central location and has no central management. It is a database that is created through the collaboration between participants and stored as individual copies on the computers of those participants. New information is declared by the information owner and is subject to objective logic verification and validation by each participant. Through a consensus process, those participants agree collectively on the information to be added to the database.
In other words, a Blockchain is a notarisation platform that is managed collectively by its participants without the need for a central trusted party. A network of participants -also called nodes- create together a database in which “transactions” are added after collective verification and agreement (for an operational overview of the functioning of a Blockchain, see our latest article “Need to Grasp Blockchain? Start with an Operational Overview!“). In the context of a Blockchain launched by the WHO to help contain the spreading of Sars-Cov-2, the network nodes are nations and the transactions consist of the registration of self declared new information on the number of infected people, their geographic location, their health status, the timing of testing and other relevant data-points.
Now, of particular interest for the implementation of a Blockchain in the given context, are its core features. A Blockchain is a real-time one-single-source-of-truth that integrates features like authenticity, integrity, decentralised validation, chronology, honesty, immutability, tamper-resistancy, transparency, auditability, accountability and un-deniability. All these features together result in a database that serves as a trusted SINGLE SOURCE OF TRUTH. Let’s have a look at these Blockchain features.
A transaction that appears in a Blockchain is guaranteed to be authentic, meaning that only the declaring party in the transaction can have signed the transaction. It’s a bit like a transaction on a bank account which can only be signed by the holder of the password, which must be the owner of the account. Let’s explain.
On the Blockchain, each nation exists through an identifier which is called a public key and is similar to other kinds of identifiers like a bank account number. This public key is visible in each self-declared transaction and has a corresponding private key -consider it as a password- which is used to compute and add a digital signature. These digital signatures are unique for each transaction because the data and timestamp of the transaction itself is combined with the private key in the computation of the digital signature. The particularity of private keys – and by consequence the digital signatures- is that they are mathematically linked to the public key.
The mathematical link between a public key, private key and digital-transaction-signature is extremely powerful because it enables anyone to authenticate a transaction based only on the data in the transaction: the public key, the transaction data and the digital signature allow a mathematical test to confirm or deny that the transaction is signed by the private key linked to the transaction’s public key.
If each country reveals its public key to the other participants, then the latter can authenticate all the transaction entries executed by another country. So, pandemic related data on the public key of a certain country is guaranteed to be published by that country, as confirmed by the mathematical confirmation on the transaction’s digital signature.
Transactions on a Blockchain are guaranteed to hold the content as created by the holder of the transaction’s public key, because it is only the original content that can confirm the correctness of the digital signature. A fraudulent party that intends to change the content of a transaction would need the private key to recreate the transaction’s digital signature. As only the owner of the public key holds the private key, this is an impossibility.
A transaction, i.e. a self-declared information entry, is signed by the information owner’s private key. As the digital signature is the result of a combination of the private key with the transaction content, and as the digital signature is mathematically verifiable relative to the public key of the owner and the transaction content, the transaction integrity can be confirmed also. If the content of a transaction has been changed from its original state, then the mathematical verification of the link between the transaction content, the public key and the transaction signature breaks down and anyone can confirm the integrity breach.
A Blockchain is maintained by a network of participants -also called nodes- which individually verify and validate transactions and collectively agree on the new content to be added to the Blockchain database. There is no one single centralised party that determines what is valid information and what is added to the database.
Each node independently validates the information for authenticity and historical coherence. The way nodes validate authenticity has been discussed in the previous section. The validation for historical coherence has as objective to avoid double accounting and confirm objective logical coherence and consists of an audit of the new information by confrontation with the data already present in the database.
Once individual nodes verified and validated new transactions, the entire network of nodes participates in a consensus process -called mining- reaching a collective agreement on the new transactions to be added to the Blockchain. After the agreement, all nodes add the agreed upon transactions to their individual local copies of the Blockchain database.
CHRONOLOGY, HONESTY, IMMUTABILITY & TAMPER-RESISTANCY
A Blockchain registers new transactions in its database in a chronological order and in a way that guarantees permanency, immutability and unalterability.
Transactions are grouped in blocks (for efficiency reasons). These blocks are timestamped and completed with a digital fingerprint that takes as inputs the block-content AND the digital fingerprint of the previous block. The format of that digital fingerprint is submitted to restrictions in such a way that a valid fingerprint is easily recognisable to anyone. In the Bitcoin Blockchain for example, the digital fingerprint of a block has to start with a series of zeros. Computing the right configuration for the block such that the fingerprint of a block respects the imposed format, is executed by miners and is an extremely difficult and expensive challenge that -if deemed done correctly by the other participants- is compensated with a reward.
In case someone tries to reorder a Blockchain or alter its transactions, the digital fingerprint will lose its requested format and everyone is alerted of the presence of non-valid content. The cost for hiding a fraud resides in the work of re-configuring the blocks again in the right way in order to obtain a chain of linked digital fingerprints that all respect the imposed format. This cost is exorbitantly high. The Blockchain protocol thus secures the chronology, immutability and tamper-resistance through economic staking: the cost of the fraud results in an overall economic loss for the fraudster.
TRANSPARENCY, AUDITABILITY, ACCOUNTABILITY & UNDENIABILITY
A Blockchain shares the content of its database with its participants and by consequence makes it auditable for all. As the content of a Blockchain database is validated by the entire network and is chronologically ordered, immutable and tamper-resistant, it becomes an instrument for notarisation, accountability and un-deniability. Because of the authenticity and integrity features described above, the transaction-initiator can not deny its involvement in the creation of that transaction. By consequence, the Blockchain and all its transactions become an absolute basis for a generalised accountability.