Vaibhav Saini

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Quantum Computing: Is it the end of blockchain?

June 3rd 2018
Is this the end of blockchain?

Experts are suggesting quantum computing may render blockchain obsolete. As the tech giants such as Google and IBM are showing interest in Quantum computing the danger is evident. According to MIT Technology Review, this type of computing can hack the cryptography hash that universally secures the blockchain and in general the internet. This would suggest quantum computers may complete fraudulent transactions and steal coins. With its exponential power, quantum computers threaten blockchain’s future security.

To successfully hack a blockchain, you would need to alter both the targeted block and all of the blocks connected, simultaneously.(source)

Blockchain security weaknesses

Blockchain consists of encrypted nodes connected on a chain, which currently makes it almost impossible to hack. The order of entries adheres to the blockchain protocol, which makes it counterfeit-resistant.

To successfully hack a blockchain, you would need to alter both the targeted block and all of the blocks connected. Blockchains are synced throughout a peer-to-peer network. In this type of system, there is no central point of failure for hackers to penetrate. For a hacker to have a chance of penetrating the network, they would need to simultaneously alter at least 51% of the blockchain.

Altering half of a blockchain seems impossible now, but the power of quantum computers could easily crack the system.
An abstract rendering of a quantum computer.(source)

Quantum computing, unlike traditional computing, uses factorials and exponentials in algorithms. The innovation of quantum computers is based on the use of qubits instead of bits.

What are qubits?

Qubits are quantum bits. A bit is the measurement of the smallest amount of data on a computer. Quantum computing is done on a smaller level than the conventional computer. These smaller qubits (pronounced like Q — bits) enable the use of quantum algorithms. Quantum algorithms use half bit strings, which can compute the binaries, zero and one, simultaneously.

Quantum algorithms use half bit strings, which can compute the binaries, zero and one, simultaneously.

Quantum computers are not confined to linear equations because they can calculate algorithms with exponentials. This innovation allows systems to solve problems more quickly over time.

So, what are we doing about it?

As the topic of Quantum computing is becoming hot, many groups have started to work upon this to safeguard the future of blockchain and internet in general.

Queuing quantum resistance

BlockDAG protocol has claimed it is the solution to the threat of quantum computers. BlockDAG, unlike blockchain, uses the tangle protocol, also known as the BlockDAG protocol. According to experts, the tangle in the BlockDag protocol offers “quantum resistance.”

Image Source: http://www.iotasupport.com/

The tangle structure resembles a tree, instead of a chain. The tree model enables faster transaction rates by removing proof of stake. If blockchain uses a proof of stake model, BlockDAG uses “proof of movement.” In BlockDAG, nodes confirm transactions based on the history of a block’s movement throughout the network.

BlockDAG follows two rules.

  • The first, references all previous blocks.
  • The second, publishes the block immediately.

The Qrl

The QRL is doing just that by generating private keys in a much more mathematically complicated way than prime factorization. Instead of top factorization, the protocol will generate private keys using hash-based cryptographic structures. In this case, it is computationally impossible to brute force a solution, something quantum computers could do with traditional blockchains.

Russian research group

Researchers in Russia say they’ve developed and tested the world’s first blockchain that won’t be vulnerable to encryption-breaking attacks from future quantum computers. The key, the researchers say, is abandoning part of what currently helps protect blockchain transactions.

In our quantum-secure blockchain setup, we get rid of digital signatures altogether. Instead, we utilise quantum cryptography for authentication.

Quantum cryptography depends on entangled particles to work, and the researchers’ system used what’s called quantum key distribution, which the researchers say makes it possible to make sure nobody’s eavesdropping on private communications.

Parties that communicate via a quantum channel can be completely sure that they are talking to each other, not anybody else. This is the main idea.

The system they’ve experimented with was tested on a 3-node (computer) network, but it’s worth pointing out that while the team is claiming victory so far, this kind of research remains hypothetical at this point, and the study has yet to undergo peer-review.

Private blockchains

Another option is to begin using private blockchains. Private blockchains, as their name suggests, are different from public blockchains in that access permissions are strictly controlled. Participants must be invited to join and need to be validated by the network creator or protocol the network creator has put in place.

This would prevent quantum computers from determining private keys from public keys since no public keys are accessible. The main detractor, however, is that private blockchains are not decentralized and distributed in the same way as public ones. Private chains can utilize tier structures, thereby creating the opportunity for factions and centralized authority. For many, this violates the philosophical underpinnings of cryptocurrencies and blockchain technology.

Perspective

Only time will tell if current efforts are enough to create true security on the blockchain. But at least for the next few years, your blockchain is still relatively safe.

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