One of my crypto students pointed me to the "Nerdcore
Hip-Hop" group MC Frontalot. Here's
a trailer for
their tribute film, Nerdcore Rising.
You can download their song
Secrets from the
Future that makes a good point about the life of crypto.
From the (slightly explicit) lyrics
Best of all, your secret: nothing extant could extract it.
By 2025 a children's Speak & Spell could crack it.
You can't hide secrets from the future with math.
You can try, but I bet that in the future they laugh
at the half-a**ed schemes and algorithms amassed
to enforce cryptographs in the past.
I don't expect a general way to break RSA or factor numbers either on
classical machines (for lack of algorithms) or quantum machines (for
lack of controlled entanglement) in the next couple of
decades. Nevertheless you can't count on say a 1024 or 2048 bit RSA
key being safe in a decade or two. Better algorithms combined with
faster highly parallelized machines may break those codes. Or maybe
they won't—but you can't be sure.
Even the NSA gives expiration dates on encrypted data. If you used
100,000 bit keys your secrets should survive into the next
century. But you have to wonder—how dark are your secrets that
you need them to last?