An overview of Grover’s algorithm
To illustrate the impact of quantum search on classical cryptography, imagine you have a symmetric algorithm with millions of millions of keys, and you are trying to find the right one to decrypt the ciphertext. Quantum search has the potential to find the right key in seconds or minutes, instead of days or even years!
Grover’s algorithm could brute force a 128-bit symmetric key in roughly 264 iterations or a 256-bit key in 2128 iterations. These iterations require a considerable number of qubits, which nowadays is only theoretically possible and not yet feasible.
The quantum search algorithm introduced by Lov Grover in 1996 is important for cryptography, but principally, it will be your introduction to the world of programming algorithms in quantum computing.
Searching for an instance in an unstructured dataset is similar to finding the correct decryption key in a set of random keys.
However, this kind of unstructured...
