This happened during a discussion of RNG entropy, and the difficulty of verifying the level of entropy in a long sequence of bits (e.g. a private key.)
A colleague of mine told me about a website that, given a sufficient quantity of output from an PRNG, had been able to deduce which application the PRNG was from. As an example, he told me that he had submitted data from OpenSSL's random number generator and the website had identified "Open SSL" as the source.
This was about three years ago. He encountered the website at a previous company he worked at.
I can't find this site by googling, and my colleague may not be able to find the URL (he's looking it up.) Not surprisingly, I'm very worried if the output from supposedly-cryptographically-secure-PRNGs is vulnerable to a distinguisher attack with trivial complexity!
If anyone here recognises this website, could they please post an answer containing its URL?