Some secrets are better kept for as long as possible.

The Pratt & Whitney F119 engine and AN/APG-77 radar system used in the F-22 were both designed between the 1980's and 90's. Their technologies are still leading edge, and vital to the military dominance of the United States. I mention this just as an example of the need to keep certain secrets for many decades.

This is problematic, because at some point, quantum computers may become practical and break the encryption algorithms used today. While the world will no doubt migrate to quantum-resistant algorithms in response, intelligence agencies are collecting and storing massive amounts of data now, in preparation for the day when quantum computers are capable of breaking modern encryption.

This presents secret keepers with a problem: we don't know what quantum computers will be capable of, but we must protect today's communications from technologies that will be invented in the future.

There are several strategies for this, but essentially we must apply massive overkill to encryption algorithms protecting sensitive data because we have no idea how fast technology will advance. One example of this is not reusing Bitcoin addresses, as that exposes signature information and weakens their quantum resistance.