Even though the end user should not worry about whether or not a technology is quantum resistant, blockchain experts and the industry as a whole should be prepared… before it’s too late!
Takamaka, a third generation blockchain entirely developed in Java, is already completely quantum resistant: the algorithm used to sign blocks and transactions between wallets and nodes is, in fact, qTesla.
Recently, Google announced a breakthrough in quantum computing: the company was able to achieve “quantum supremacy”.
In traditional computing, a “bit” can exist in one of two states: “0” or “1”. However, quantum computers use “qubits”: they can also be either “0” or “1” but, thanks to the superposition principle, these two states can be linearly combined. This significantly increases the processing power of quantum computers.
In blockchain cryptography, it is quite difficult (if not impossible) to calculate the value of a private key starting from a public key. In order to do this, machines should be able to solve a problem called “discrete logarithm of the elliptic curve”, which would take a very long time (millions of years) even for a modern supercomputer.
However, quantum computers are so fast they can perform these calculations in just under 10 minutes!
The issue of quantum computing is nothing new for cryptography: it has been talked about for quite some time and the “race” to develop a quantum resistant technology is still on. It is assumed that quantum resistant technologies will be available within the next 5 years. However, in the blockchain field there are already some concrete examples of quantum resistant products.
Takamaka’s transaction signing algorithm is ED25519
In order to make something “quantum-safe”, a completely different approach is needed: the Takamaka project is already prepared to face these challenges.
Giovanni Antino, CTO of Takamaka, said:
“Takamaka is an emblematic example, because the way the signature algorithm is specified is well defined and clear. Notably, the block signature algorithm is already qTesla. ED25519 (High-speed high-security signatures), a public key system, is used to sign transactions carefully designed for different levels of verification and implementation: it allows to reach a high network speed without undermining security.”
Although this signature is not exactly “quantum resistant”, to date there is no computer powerful enough to compromise it. However, if such a computer should appear, it will immediately be replaced with a q-resistant technology.
Takamaka’s CTO explained:
“The cryptographic system change is already supported and implemented in the Takamaka protocol. Transactions already sent will be covered by the ‘qTesla envelope’ and the sha3-512 hash. The reason why Takamaka does not currently apply qTesla to transactions is mainly due to the size of the signature this would generate, about 14 kilobytes. It would significantly affect the size of the transaction, which is just 600 bytes.”
The stakes are high: quantum computers may soon be able to decrypt all encrypted information, including bank accounts and government databases. For cryptographers, cryptocurrencies and blockchain, time is of the essence.