<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi Halil,<div class=""><br class=""></div><div class="">I implemented this feature on Signal iOS and can confirm that messages are end-to-end encrypted.</div><div class=""><br class=""></div><div class="">1) The iPhone registers for push notifications.</div><div class="">2) When a message arrives, and the app is not in the foreground, a push notification is sent (it is constant size) and contains <b class="">no metadata on sender or even encrypted content.</b></div><div class="">3) When the iPhone gets that push notification, it doesn’t display anything to the user but open a socket in the background to the Whisper Systems web socket to fetch the message payload. Decrypts it. Checks the user’s notification display style preference. And shows relevant information.</div><div class=""><br class=""></div><div class="">So to sum up, APNS is just used as a “wake-up” signal to tell the recipient’s phone that a message is available.</div><div class=""><br class=""></div><div class="">Best,</div><div class=""><br class=""></div><div class="">Frederic</div><div class=""><br class=""><div class=""><div><blockquote type="cite" class=""><div class="">On 23 Feb 2016, at 13:40, Halil Kemal Taşkın <<a href="mailto:haliko87@gmail.com" class="">haliko87@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="content-type" content="text/html; charset=utf-8" class=""><div dir="auto" class=""><div class=""></div><div class=""><span style="background-color: rgba(255, 255, 255, 0);" class="">Hi Trevor,<br class=""><br class="">Then just to clarify things, please kindly check the attached screenshot of my iPhone. I want to figure out what I am missing?<br class=""><br class="">To test the system, my friend Murat wrote me a message: "This message should be encrypted.".<br class=""><br class="">And the message itself is directly shown in the notification as you can check from the screenshot. This is actually what I want to point out.<br class=""><br class="">If you are familiar with mobile development and push notification services, this means, the message travelled through Signal's app server's push handler and Apple APNS as plaintext.</span></div><div class=""><span style="background-color: rgba(255, 255, 255, 0);" class=""><br class=""></span></div><div class=""><span style="background-color: rgba(255, 255, 255, 0);" class="">Screenshot: </span><a href="https://www.dropbox.com/s/euy5a98v0ej9jyb/SignalNotification.png?dl=0" class="">https://www.dropbox.com/s/euy5a98v0ej9jyb/SignalNotification.png?dl=0</a><span style="background-color: rgba(255, 255, 255, 0);" class=""><br class=""><br class="">Regards,<br class="">Halil Kemal TASKIN.</span></div><div class=""><br class=""></div><div class=""><br class="">23 Şub 2016 tarihinde 11:51 saatinde, Trevor Perrin <<a href="mailto:trevp@trevp.net" class="">trevp@trevp.net</a>> şunları yazdı:<br class=""><br class=""></div><blockquote type="cite" class=""><div class=""><span class="">On Tue, Feb 23, 2016 at 1:41 AM, Halil Kemal Taşkın <<a href="mailto:haliko87@gmail.com" class="">haliko87@gmail.com</a>> wrote:</span><br class=""><blockquote type="cite" class=""><span class="">But your message is also sent in plaintext for push notification issues.</span><br class=""></blockquote><span class=""></span><br class=""><span class="">Hi Halil,</span><br class=""><span class=""></span><br class=""><span class="">Your description is wrong - Signal works as Raphael describes.</span><br class=""><span class="">Plaintext content for encrypted messages is not sent through push</span><br class=""><span class="">services.</span><br class=""><span class=""></span><br class=""><span class="">Trevor</span><br class=""></div></blockquote></div>_______________________________________________<br class="">Messaging mailing list<br class=""><a href="mailto:Messaging@moderncrypto.org" class="">Messaging@moderncrypto.org</a><br class="">https://moderncrypto.org/mailman/listinfo/messaging<br class=""></div></blockquote></div><br class=""></div></div></body></html>