Reading about the Logjam attack, I learned that Diffie-Hellman exchanges often* rely on the same particular 1024-bit key. I understand that back when DH was invented, even 512-bit keys were considered secure for decades to come. But did it never occur to the designers, or to many of the programmers who have worked on DH implementations over the years, that reusing the same primes could lead to an eventual (catastrophic) vulnerability?
Am I missing something with the computational difficulty? Generating your own p and g once, at the initial configuration of the service, ought to be enough and should guarantee immunity from any flaws with the standardised primes.
*: As in, two-thirds of current worldwide implementations often.