&quot;Cryptographically secure&quot; sounds like a vague thing you bring up here.  To me, it sounds it is by definition secure (and cryptographically so, if they use cryptography) against passive attackers (and probably nothing else), but I am not really debating abstract and fuzzy definitions here.<p>My objection is very concrete: to say whatever uses JavaScript cryptography is as secure as TLS is false. Precisely, what it means is <i>for all</i> threat models imaginable, if you can somehow subvert TLS, you can <i>always</i> break the JavaScript crypto, and this is obviously false at least for one scenario I described in the other comment. We could reasonably debate the likelihood of the scenarios, but it&#x27;s really hard to argue the mathematical equivalence of the two.