[Cryptography] QM giveth, QM taketh away

[jrzx]

> As for all the hand-wringing, I am reminded of this:
> "We can factor the number 15 with quantum computers. We can also
> factor the number 15 with a dog trained to bark three times."
> --- Robert Harley, 5/12/2001, Sci.crypt.
>
> Twenty years later, the snake oil comes in larger bottles:

What number can we factor today?

The next number with two unequal factors is twenty one.  Has twenty one been factored yet by Shor's algorithm?