Quantum Computing: Impact on Blockchain Technology

Aditya Sahu
Jul 20 · 3 min read

Blockchain Technology has been around the tech world for more than a while now. It has indeed indulged business professionals and large industries all around the world to invest their money into a pool of digital currencies, called the cryptocurrencies. The technology is known for its superlative level of security which uses a decentralized, peer-to-peer network of systems all of them sharing a common database, thus eliminating the need of a third-party, a centralized server. Some platforms that use Blockchain Technology are Bitcoin and Ethereum have made their way deep into the industry.

Before we go further, let’s see how Blockchain secures your data.


Cryptography Methods Used by Blockchain Technology

Public key cryptography has been an essential part of Bitcoin’s protocol to ensure integrity of transactions created in the protocol. In fact, almost all of the Blockchain based platforms use Public Key Cryptography.

So, what is it really?

It is a security protocol encryption technique which generates a pair of public key and private key for the user to digitally verify the owner of the transaction. Private key is only known by the owner of the transaction while public key is accessible to anyone. Assuming that a classical computer tested a trillion keys a second, it would take up to 1.09 x 1019 years to guess the correct private key. When combined with blockchain protocol, it has been found highly secure as the attacker would require more than half of the computational power of the machines connected to the chain and in a really short amount of time in order to hack it.


Hmm.. so how does Quantum Computers affect Blockchain Technology?

To answer the question, let us understand what Quantum Computers are and how do they pose a threat to the existing public key cryptography algorithms. Unlike the conventional computers that have been here for more than half a century which use binary digits: 0 and 1 for processing, quantum computers use quantum bits or “qubits” that can exist in any superposition of values between 0 and 1 (yes, the grey area). As a result, quantum computers are said to work about a 100 million times faster than classical modes of computation.

And using Shor’s Algorithm and Grover’s Algorithm for quantum computing, the current existing algorithms of public key cryptography can be very easily broken by Quantum Computers. But given the primitive state of quantum computers today, it is safe to say that this will not be happening anytime soon. It gives us roughly 8–10 years till quantum computers reach the maturity level and ready to be used worldwide.

However, this doesn’t mean that we should sit back and relax, stop worrying about it and face when the future comes. The current cryptographic algorithms are not used just by the blockchains, but also by almost every product. Thus, there is a need to be extra careful in future and find more secure cryptographic solutions to avoid the pitfall, as the time is ticking and Quantum Computing is making its way through the industry!

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