Messages sent using classical crypto should be viewed as being public after an unknown delay. They can be decoded at your adversary's leisure with techniques and equipment invented in the future.
Quantum cyrpto must be broken immediately to be broken at all.
If what you are encrypting is, for example, credit card information, it's perfectly fine if that becomes public in a decade. Your information will have changed.
If what you are encrypting needs to remain secret for the next fifty years, do not use classical encyrption and a public channel. It may well be made public while the information is still sensitive. This is why QKD has some early adopters. It's the only long-term secure alternative to having people carry one time pad's back and forth in suitcases full of hard drives, which has its own security issues.
Messages sent using classical crypto should be viewed as being public after an unknown delay. They can be decoded at your adversary's leisure with techniques and equipment invented in the future.
Quantum cyrpto must be broken immediately to be broken at all.
If what you are encrypting is, for example, credit card information, it's perfectly fine if that becomes public in a decade. Your information will have changed.
If what you are encrypting needs to remain secret for the next fifty years, do not use classical encyrption and a public channel. It may well be made public while the information is still sensitive. This is why QKD has some early adopters. It's the only long-term secure alternative to having people carry one time pad's back and forth in suitcases full of hard drives, which has its own security issues.