It's definitely a bug, most likely in the pre-prime generation (not enough entropy).
If we're talking 1024-bit integers created by multiplying two 512-bit primes, the facts are:
1) The number of 512-bit primes is estimated around 11.36×10^150
2) The chance that two truly random primes are the same is one in 3.37*10^75. It is safe to assume it has never happened and never will (at least on our current hardware).
> We’re only at 10^7 so far. As Heninger said in her talk, we have enough 512-bit primes to assign a public encryption key to every atom in the universe, with little worry over possible duplicates.
I find the scale of these numbers absolutely incredible.
If we're talking 1024-bit integers created by multiplying two 512-bit primes, the facts are:
1) The number of 512-bit primes is estimated around 11.36×10^150
2) The chance that two truly random primes are the same is one in 3.37*10^75. It is safe to assume it has never happened and never will (at least on our current hardware).