This article is from the PGP FAQ, by Jeff Licquia email@example.com with numerous contributions by others.
This question has been asked many times. If the NSA were able to crack
RSA, you would probably never hear about it from them. The best
defense against this is the fact the algorithm for RSA is known
worldwide. There are many competent mathematicians and cryptographers
outside the NSA and there is much research being done in the field
right now. If any of them were to discover a hole in RSA, I'm sure
that we would hear about it from them. I think that it would be hard
to hide such a discovery. For this reason, when you read messages on
USENET saying that "someone told them" that the NSA is able to break
pgp, take it with a grain of salt and ask for some documentation on
exactly where the information is coming from.