Zbkx Extension

Versions

1.0.0
State

ratified

Ratification date

== Synopsis

Adds instructions to implement a "lookup table" for 4 and 8 bit elements inside the general purpose registers.

These instructions are useful for expressing N-bit to N-bit boolean operations, and implementing cryptographic code with secret dependent memory accesses (particularly SBoxes) such that the execution latency does not depend on the (secret) data being operated on.

Instructions

The following instructions are defined by this extension:

xperm4

Crossbar permutation (nibbles)

xperm8

Crossbar permutation (bytes)