Editing Privacy-Enhanced Mail (section)

== Privacy-enhanced mail ==
The PEM format was first developed in the privacy-enhanced mail series of [[Request for Comments|RFCs]]: RFC 1421, RFC 1422, RFC 1423, and RFC 1424. These standards assumed prior deployment of a hierarchical [[public key infrastructure]] (PKI) with a single root. Such a PKI was never deployed, due to operational cost and legal liability concerns.{{citation needed|date=May 2017}} These standards were eventually obsoleted by [[Pretty Good Privacy|PGP]] and [[S/MIME]], competing e-mail encryption standards.{{citation needed|date=May 2017}}