It does not even break classical encryption (though classical encryption needs higher security margins if attacks using quantum computers are possible). It bre

It does not even break classical encryption (though classical encryption needs higher security margins if attacks using quantum computers are possible). It breaks only classical public-key encryption. Public-key encryption is not necessary within a closed organization, e.g. for the personal use of an individual or group of individuals, or within a spy agency or for military applications, though it can make slightly simpler the process of key distribution, which otherwise needs an initial physical pairing between devices. The most important application of public-key encryption is for allowing relations between parties who have never met in person, by the use of digital signatures and of Diffie-Hellman key establishment protocols. This has been essential to enable online shopping and online banking, but not for the more traditional uses of cryptography.