They break all widely used public key encryption systems (RSA, DH, ECC-based). There are post-quantum systems, but none of them are in widespread use yet. Symm

They break all widely used public key encryption systems (RSA, DH, ECC-based). There are post-quantum systems, but none of them are in widespread use yet. Symmetric encryption systems are weakened, but can easily be made quantum safe by increasing the key size.