Glossary
Quantum computing
Quantum computing is based on the principle of quantum physics, developed by Planck, Einstein, Bohr, and several other physicists in the early 20th century. In the quantum realm, the superposition of states is possible; that is, a value cannot be defined, but in principle it can be any value from a set. This leads to the possibility of performing several mathematical operations simultaneously, which represents an unprecedented increase in the computational power of a computer. Such kind of behavior is not possible on classic computers.
Quantum computers are still in their early stages of development, but they promise a significant increase in computational power. This could lead to the breaking of several cryptographic algorithms currently considered secure. This is because most cryptographic algorithms today are based on the discrete logarithm problem or the factorization of large prime numbers. These problems are deemed safe because their solution would depend on computational power that cannot be obtained by classical computers nowadays.
If quantum computers fulfill their promise and significantly increase computational power, such estimates would be broken, and it would be possible to break the most used cryptographic algorithms. As blockchain security is maintained by cryptography, they must prepare for this.
Fortunately, blockchains have additional security to the problem of quantum computing, which is the fact of using hash functions. Unlike the problem of discrete logarithms or factoring large prime numbers, hash functions are resistant to quantum computers.
The problem with the emergence of quantum computers would affect not only the blockchain environment but the Internet as a whole. Most Internet sites today are considered secure because they use RSA encryption, which is resistant to classical computers but not quantum computers. RSA is based on the factorization of large prime numbers.
Quantum computers pose a threat to the current security and privacy of networks, but it would not be the first time that a cryptographic algorithm has been broken by cryptanalysts. History has shown a constant struggle between cryptographers, who try to create unbreakable algorithms, and cryptanalysts, who try to break them. Every time a scheme is broken, an even more secure scheme is developed.
Due to this threat from quantum computers, new algorithms are already being developed. Called post-quantum, or quantum-resistant cryptography, such algorithms would be safe from cryptanalytic attacks by using quantum computers. The story of cryptography will continue a battle between cipher makers and cipher breakers, now in the quantum realm.
