<story><title>What Is the Signal Encryption Protocol?</title><url>https://www.wired.com/story/signal-encryption-protocol-hacker-lexicon/</url></story><parent_chain></parent_chain><comment><author>baby</author><text>For anyone curious, I spent a lot of time describing the protocol in intuitive ways[2] in the book Real-World Cryptography[1].&lt;p&gt;Having spent a lot of time reviewing Signal and secure messaging applications as part of my job, I wanted to be able to explain how the protocol worked in the most educative way possible. feedback is welcomed :D&lt;p&gt;[1]: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.manning.com&amp;#x2F;books&amp;#x2F;real-world-cryptography?a_aid=Realworldcrypto&amp;amp;a_bid=ad500e09&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.manning.com&amp;#x2F;books&amp;#x2F;real-world-cryptography?a_aid=...&lt;/a&gt;&lt;p&gt;[2]: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;livebook.manning.com&amp;#x2F;book&amp;#x2F;real-world-cryptography&amp;#x2F;chapter-10&amp;#x2F;v-10&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;livebook.manning.com&amp;#x2F;book&amp;#x2F;real-world-cryptography&amp;#x2F;ch...&lt;/a&gt;</text></comment>
<story><title>What Is the Signal Encryption Protocol?</title><url>https://www.wired.com/story/signal-encryption-protocol-hacker-lexicon/</url></story><parent_chain></parent_chain><comment><author>upofadown</author><text>This article mentions an important fact about forward secrecy:&lt;p&gt;&amp;gt;Perfect forward secrecy is useless, it&amp;#x27;s important to note, if users don&amp;#x27;t delete their messages periodically.&lt;p&gt;Then:&lt;p&gt;&amp;gt;The Signal app offers disappearing messages that are automatically deleted after a certain time limit.&lt;p&gt;Which is not turned on by default. The user has to somehow know that they have to do this to get the benefit of forward secrecy. This seems all too common with contemporary encrypted messaging stuff. Really great features that depend on having the users behave in a way they normally would not.&lt;p&gt;Of course the app can do this wrong simply by failing to do a secure delete that actually removes the messages from the storage device. In the end the actual communications protocol doesn&amp;#x27;t make very much difference in the face of counter productive implementations; conceptual and&amp;#x2F;or technical.</text></comment>