3 ms·
The state representing the number of attempts must be stored somewhere, and thus a determined adversary could eventually corrupt it. Look, there's a big differ
by cromwellian 11y ago
The state representing the number of attempts must be stored somewhere, and thus a determined adversary could eventually corrupt it.
Look, there's a big difference between trusting known ciphers that have been well studied by the world's top cryptographers, and a proprietary TPM chip that relies on security-through-obscurity.
The history of embedding secrets into black boxes is a history of them being broken. This isn't a theoretical concern, it's a very practical one.
- Piskvorrr 11y agoKerckhoff's principle should be adhered to if truly secure encryption is desired; alas, then all sorts of hard obstacles pop up (UX becomes a SPOF, most commonly - a secret always needs to be stored somewhere, if only in the user's head). OTOH, the practical purpose of encryption is to remain unbroken for long enough, not to be completely unbreakable. As seen here, security-through-obscurity is practical enough in cases where user-obtained key material is too weak to provide enough protection using strong publicized crypto. In other words, it's a two-part key: one is in user's wetware, the other in phone's hardware (as per obXKCD, it's usually easier to attack the former).
- Dylan16807 11y agoThe question is not whether a determined adversary could corrupt the counter. The question is whether they can corrupt the counter before they corrupt something else that causes total data loss. Physical defenses are not security through obscurity, and why you assuming they don't use known ciphers?