On: What I learned from my first C coding challenge

[masterzora]

Quoth the parent: "It does not apply here"

[tptacek → masterzora]

Sure. The flaw here isn't strcmp. In fact, most crypto compares don't use strcmp, even in naive code; an HMAC-SHA1 MAC, for instance, is an array of 8-bit bytes, not the hex string that programs encode them into for human consumption. "memcmp" is the normal culprit.

Timing attacks aren't a flaw in memcmp or strcmp. Touching every byte of a string is stupid behavior in the overwhelming majority of cases.

[Xuzz → tptacek]

Unless, of course, you're Nintendo: http://wiibrew.org/wiki/Signing_bug

[tptacek → Xuzz]

Good find. Again, notice how the problem here isn't strcmp or it's timing behavior; it's mistakenly using ASCIIZ strings to hold ciphertext.