Well, several years ago, at least PGP 5.0i built on MPE/iX...
http://www.editcorp.com/Personal/Lars_Appel/pgp/
also see a slightly older paper...
http://www.editcorp.com/Personal/Lars_Appel/pgp-ix.html
Note, however, that you will get in trouble if your file size
reaches 2 GB, due to limitations of the POSIX API on MPE/iX.
And, moreover, you might have to solve the issue of getting
a license to run PGP 5.0i outside of personal privacy usage.
Lars.
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