Displaying 1 result from an estimated 1 matches for "secret_lookup_idx".
2019 Sep 12
2
Side-channel resistant values
...and often our only resort is to fall back to writing in plain
assembly.
Let me give you an example: https://godbolt.org/z/b1-0_J
In this code, the programmer instructs the program to select a value
from the lookup table using a scanning approach, in an attempt to hide
the secret lookup index in `secret_lookup_idx`.
However, LLVM is smart and skips the memory lookups whenever i !=
secret_lookup_idx, exposing the function to cache side-channel attacks.
Now how to prevent this? Most tricks, for example using empty inline
assembly directives[1], are just ugly hacks.
So I am wondering: Is there any support fo...