How do we know a cryptographic primitive won't suddenly fail? It took more than a decade from when MD5 looked like it was going to break to the point when it was actually broken. That's more than a decade of warning. One might suspect that we were fortunate that we got all that time. Even so, it took a long time for the world to move away from MD5.

How can we be sure that when our cryptosystems are flawed, that we'll have enough warning time to change them?

How can we be sure that, say, ECC won't get broken overnight?
We don't.${}{}{}{}{}{}{}{}{}{}$

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