Quantum blockchain is being developed in Russia:
A team of blockchain and cryptography developers in Russia are developing quantum-resistant blockchain. This is commendable, because blockchain as we know today is secure, however, once quantum computers are commercialized, today’s technology underpinning blockchain will no longer be secure.
Key technology components of today’s blockchain:
Without going into every single component that make up today’s blockchain, we will look into two major technology components constituting blockchain today. These are the encryption technology and transaction validation through consensus algorithm.
Participant nodes in today’s blockchain mainly use public and private keys encryption technology, to authenticate themselves and their transactions. In this technology there are two keys. The public key is published, this is not secret. Another user can post a message to the node in question using the public key. The private key is the secret one, and only the node that owns that private key should know it. This allows only the node in question to decrypt the message and process it. The public key can be constructed from the private key. However, it’s extremely difficult to construct the private key from the public key, because these are linked by integer factorization. Take the number 3,296. This can be expressed as 2x2x2x2x2x103. Hence, there are 2 integer factors making up 3,296, and these are 2, and 103. If the number is much larger, then we will take very long time to identify the factors. The computer may take less time than us, but even it will take a significant amount of time, when faced with a very large number. The public and private key encryption technology uses extremely large numbers that will make today’s computers take several billions of years to arrive at the integer factors! This is what makes public and private keys encryption technology so secure.
In blockchain, which is a decentralized system, a network of computers, also called ‘nodes’, maintain a shared version of truth. Every node has equal authority, and updates to blockchain needn’t be routed through any central authority. No existing record can be deleted or modified, hence the only way to update blockchain is to add a new block record, also called ‘block’. Since every node can potentially add a new block, it’s vitally important to maintain the order of transaction accurately, without which data integrity will be compromised. Blockchain addresses this using consensus mechanism. This may mean proof of work (POW) consensus algorithm, where majority of all participant nodes have to validate a new transaction. Alternatively, in proof of stake (PoS) consensus algorithm, there are specific nodes that take transaction validation responsibility, and they stake their crypto tokens for this purpose, and a majority of them will need to validate a new transaction. Irrespective of the consensus algorithm, getting a transaction validated will require solving a complex cryptographic puzzle, which means massive number-crunching operation at high-speed. Since all nodes on today’s blockchain have significant computing resources at their disposal, and it’s a decentralized network, no one can hijack the majority of transaction approving nodes and play havoc with the system. This is what makes blockchain secure.
Quantum computers can hack today’s blockchain:
The above-mentioned technological components in today’s blockchain make it secure, because today’s computers, which can be called ‘classical computers’, don’t have processing power to hack these security measures. Classical computers store information in binary format, in ‘bits’, i.e. one bit can only have a ‘0’ or ‘1’ at a time, and not anything else. That’s changing with quantum computers, which are currently in a stage of research, development and refinement, and not yet commercialized. Quantum computers store information in quantum bits, or ‘Qubits’, which can hold a superposition of ‘0’ and ‘1’ states at any time. Algorithms used for processing qubits are called ‘quantum gates’, which are building blocks operating simultaneously on all possible states of all qubits. More qubits mean more processing powers, and quantum computers can operate much faster than classical computers. Integer factorization of a very large number which will take several billions of years for classical computers will take only a few days with a quantum computers. The public and private key encryption technology won’t be safe anymore when quantum computers are commercialized. Additionally, if a node employs a quantum computer in today’s blockchain network, then it can easily overpower combined computing power of all other nodes, delete transactions even before they are recorded on the blockchain, and create transactions before anyone else potentially violating data integrity in blockchain. Among the two key security measures underpinning today’s blockchain, the encryption may be threatened by quantum computers first. According to a research done by a group of students in the National University of Singapore, at least for the next decade, the powerful computers employed in today’s blockchain nodes will maintain a lead over the quantum computer in terms of processing power.
Blockchain and encryption experts are formulating response to quantum computers:
While the threat from quantum computers may still be a decade or more away, it’s heartening to note that the blockchain and encryption experts are already looking ahead and mounting responses.
- A team of blockchain and cryptocurrency developers are developing QRL, or Quantum Resistance Ledger. Encryption technology without dependence on integer factorization is being developed.
- In USA, the National Institute for Standards and Technology (NIST) is evaluating proposals for encryption technologies that can resist quantum computers.
- The Russian Quantum Center is expanding their research with the objective of developing blockchain solutions that can withstand attack from quantum computers.
