The answer to this question is not straightforward, as it depends on several factors, including the specific encryption algorithm used and the assumptions made about the capabilities of quantum computers. However, it is widely accepted that sufficiently large-scale, error-corrected quantum computers could potentially break widely used asymmetric encryption algorithms, such as RSA and ECC (Elliptic Curve Cryptography).
The security of these encryption algorithms is based on the difficulty of factoring large numbers or solving the discrete logarithm problem, which are computationally intensive tasks for classical computers. Shor's algorithm, a quantum algorithm, has the potential to solve these problems significantly faster than classical algorithms.
To break RSA and ECC, Shor's algorithm requires a large number of qubits and highly reliable qubits, as well as the ability to perform error correction to mitigate the effects of noise. The exact number of qubits required is not definitively known, but it is generally estimated that several thousand to millions of logical qubits would be necessary.
practical quantum computers have not reached the scale required to break these encryption algorithms. However, quantum computing technology is advancing rapidly, and it is difficult to predict when large-scale quantum computers capable of breaking such encryption will become a reality. It is essential for cryptographic systems to evolve and transition to quantum-resistant algorithms before that point is reached, ensuring the security of sensitive information.