That let me think: I think I have never compiled af_alg in any of my linux kernels.
Now, I worry about the linux user mount namespace code... because I run the steam client which valve forces people to have in their kernel because they don't want/know how to craft "correct" ELF64 binaries, namely "-static-libgcc -static-libstdc++" compiling/linking options, maximizing static linking refactoring a bit source code with the pre-processor to avoid symbol collisions.