The heart and bloodline of any blockchain is the cryptography. Cryptography is the tool that provides the basic functionality of the blockchain system. The Blockchain architecture implies that the trust which exists between the participants of the Blockchain network is based on the concepts and principles of maths and economics.
Cryptography guarantees safety, transparency, and verifiability on all operations made on the blockchain network; in contrast to the crypto industry’s traditional approach of limited and restricted visibility of the blockchain system’s critical parts (perimeter security).
The hash function makes the cryptography the basis of most existing crypto coins and digital currencies. It is able to map out an input data of arbitrary size to a data made up of a fixed size. This is to say that it converts a random length data array into a bit string of a fixed length.
It should be known and noted that this operation is irreversible; in other words, in the function f(x)=y, we can be able to find y if we know x, but we are unable to find the value of x by knowing y.
In Bitcoin, the role of such function is usually performed by the SHA-256. Another essential feature of hash functions which is very vital and important is the fact that even the smallest change of input data can result in a drastic change of hash.
In essence, the hash functions application in the blockchain is to allow and guarantee the integrity of the entire chain of transactions.
Every new transaction block would refer to the hash of the former block in the ledger. The hash of the previous block rather depends on all the past transactions made in the block; but instead of passing the hash consequently from one transaction to the next transaction.
All of the hash functions would be fused in a single hash line of the most recent transaction with the aid of a binary hash tree (Merkle tree).
The Merkle tree
With the use of the hash function, you can easily express the general state of a blockchain. This is to say that all previously performed transactions and their chronological orders can be ascertained with a single line which is the hash of the most recent block. So, the immutable nature of any block’s hash guarantees the immutability of the entire blockchain.
The quantum threat
The Quantum computers are computational machines and devices of a fundamentally new level, which significantly surpassing the existing ones in terms of it’s computing power.
IBM 50 qubits quantum computer
In traditional or local computing, one unit of information processed is a bit. For every bit can only be in just one of two possible states which are 0 or 1. In quantum devices, qubits (quantum bits) are majorly used instead of bits.
The major difference from the bits is the ability for it to be in the state of 1, 0, & also be in the state of 1 and 0 simultaneously (superposition).
In classical computations, only one of the 2^n data variants would be loaded into the computer’s memory. So, just one of the possible 2^n data sets gets to be processed at a particular time. However, inside the quantum computer’s memory, all of the 2^n combinations of the initial data is present and they get processed simultaneously.
This means that the function for all the possible 2^n variants of a definite data set is calculated during a single operation (which at the end, only one solution will be obtained). With this way, the computing power of quantum devices will aid in obtaining a private key using with the use of the Shor’s algorithm (lowering its resistance and applying new calculation methods).
Today, there are just a few primary methods that provide protection from the quantum computer attacks: Hash-based cryptography, Code-based cryptography, multivariate cryptography, Supersingular elliptic curve isogeny cryptography, Symmetric key quantum resistance, and Lattice-based cryptography
With the use of long keys and following proper security requirements are methods can help to resist both the classic attacks and the quantum attacks. Unfortunately, because of the technical challenge and the large size of the quantum-resistant signatures, the existent solutions cannot match the forthcoming threat.
This is why the developers of cryptocurrencies such as Bitcoin, Ethereum, NEO are seeking ways on how to solve this problem. But there are several projects like the GEO Protocol which are already making use of the post-quantum cryptography as it’s base technology to protect their records and data.
One major feature of the GEO Protocol is that it is not based on a common ledger rather it is blockchain agnostic. That enables it to connect various blockchains and to non-blockchain-based assets. The transactions made are performed only by the local off-chain consensus of the participating nodes.
All data are saved and stored by the nodes, between which composite channels are installed. Note that composite channels are a combination of the state channels and trust lines.
On the GEO network (GEO is a non-blockchain solution) every node stores its current balances and gets to credit relationships with all the neighboring nodes. This peculiarity of the protocol, and with the lack of a commonly distributed ledger allows us to use one of the perfect ways to solve the quantum problem which is the Lamport signature.
The essence of using this method lies in using one-time keys for each transaction. The keys are generated in advance and there are made in limited quantity. When the pre-generated keys are used, new keys will be generated. This helps us to conduct an unlimited quantity of transactions securely, safely and quickly.
Ever wondered why most cryptocurrency projects and startups don’t seem to care about the quantum threat? The quantum threat rarely gets discussed at blockchain-related conferences.
But this could all change in the nearest future, as the quantum computing breakthrough renders the current encryption methods obsolete. With this possibility of this impending danger, the community should remain watchful and vigilant and should also make moves to fight this threat.
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