The　e-health　system　enables　online　healthcare　by　supporting　health　data　transmission　services　on　medical　platforms.　Considering　the　frequent　privacy　breaches　in　e-health　systems　and　the　issuance　of　relevant　regulations,　it　is　important　to　ensure　the　authenticity　and　privacy　of　health　data.　Existing　e-health　systems　either　fail　to　provide　data　authenticity　or　neglect　privacy　protection　after　patients　leave　the　system.　In　this　article,　we　put　forward　a　secure　and　efficient　e-health　system　for　data　transmission,　named　PPED,　to　solve　this　dilemma.　In　PPED,　we　explore　a　regular　signature　and　a　forward-secure　signature,　which　guarantee　data　authenticity　and　give　the　signature　a　valid　period.　Then,　a　specific　epochal　signature　scheme　is　designed　by　combining　two　signature　schemes　with　the　time-lock　puzzle.　Since　expired　epochal　signatures　are　forgeable,　patients　after　leaving　the　e-health　system　can　forge　expired　signatures　to　deny　their　relationship　with　the　signed　data,　thus　achieving　privacy　protection.　Detailed　security　analysis　demonstrates　the　PPED　realizes　data　authenticity　and　user　privacy.　Extensive　experiments　evaluate　our　system　and　the　results　show　it　is　practical　in　terms　of　running　time.　©　2008-2012　IEEE.