From: "P. J. Ponder" <ponder@freenet.tlh.fl.us>
the point is that the source code is available and public. I may not be able to find any errors or hiddens trapdoors in it, but I have greater trust in it because many other people can read it and make public comments about it. the advantage of a published (public) work is that even those of us who are not experts can gain the advantage of having the work reviewed openly by anyone who is so inclined.
People would do well to remember this. In the future software released by PGP Inc. will not come with source code. I don't believe source to PGPfone will ever be released, for instance. Beware of this software. Despite Zimmerman's strong privacy record, you should never, ever, use crypto software that doesn't come with source. Period.