Phil Zimmermann wrote the encryption program PGP, and nearly went to jail over it. He sold his company to Network Associates, which barely seemed interested in marketing the program. Now NAI has not decided to stop selling PGP, but now NAI Tells Sites To Remove PGP, under threat of prosecution under the Digital Millennium Copyright Act (the DCMA). [Source: Slashdot]
Seems to me that NAI has the right to do with PGP what it wants; it owns it, and can sell it or not as it so wishes. It also can insist that other people not distribute it. The techology is out there, however, and other people have built software based on the PGP algorithm. You should use it.
Here’s what Zimmermann himself has to say about NAI’s non-promotion of his program. Keep in mind that he’s not a lawyer, and the page doesn’t directly address the current question. But it’s interesting nonetheless.