• Alpine Messaging System-- for Windows and Unix
  Alpine is a fast, easy to use email client that is suitable for both the inexperienced email user as well as for the most demanding of power users. Alpine is based on the Pine® Message System, which was also developed at the University of Washington
  in Unix & Computing with alpine bsd client email linux newsreader opensource pine unix windows by 2 users
• PGP4Pine (aka "PAPP") PGP4Pine
  PGP to be used with alpine an pine, plugin, if you do not know what alpine is, this is not for you. PGP4Pine, also known as "PAPP" ("Pine And PGP") is a perl script to integrate pgp into the popular mail reader ("MUA") Pine. It is based on Aldo Valente's "PAPP" (which in turn integrates several scripts from Roland Rosenfeld)
  in Privacy with email encrypted encryption gpg mail pgp pgp4pine pine plugin privacy private secure

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