Tootfinder

Someone needs to make a flowchart for this.
#PGP (Pretty Good Privacy) is the proprietary tool. The open standard developed from it is called #OpenPGP. This standard was implemented by a tool called #GPG (GNU Privacy Guard), who took up the development of the standard, until they've decided they don't like where others are pushing it, so they've forked the standard into #LibrePGP. Then GPG was forked into #FreePG to bring (newer) OpenPGP into it.