"Cryptographically secure" sounds like a vague thing you bring up here. To me, it sounds it is by definition secure (and cryptographically so, if they use cryp

"Cryptographically secure" 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. My objection is very concrete: to say whatever uses JavaScript cryptography is as secure as TLS is false. Precisely, what it means is for all threat models imaginable, if you can somehow subvert TLS, you can always 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's really hard to argue the mathematical equivalence of the two.