3 ms·
That design is not obviously impossible to make work, but have you thought about timing attacks? There is no obvious way to make JS take key- and data-independe
by JoachimSchipper 15y ago
That design is not obviously impossible to make work, but have you thought about timing attacks? There is no obvious way to make JS take key- and data-independent time to encrypt something. (Turning this into a usable attack is nontrivial, obviously.)
- Estragon 15y agoWhat kind of vulnerability would a timing attack expose, in the use case I outlined?
- JoachimSchipper 15y agoIt could conceivably leak the key and/or data being sent. If the key is random, leaking it does not expose unrelated data; and if you're uploading via HTTPS, exposing the key does not even expose the protected data unless the attacker also has access to S3. Data-dependent timings could conceivably allow a bad guy to deduce something about the data being sent. Note that this is all highly speculative; I'm not convinced it's truly impossible, but it's one of those attack scenarios where "put a gun to the sysadmin's head" begins to look like a pleasant and trouble-free option...