[_0w8t]

NaCL verifier is just a loop that essentially matches the instructions against a white list and checks their format and offsets. WebAssembly needs parser/linker/optimizer/assembler. Granted that the format is optimized for fast translation, but just the amount of code to support data structures in the implementation like maps, lists etc. must be big.

[Houshalter]

NaCL also needs those things because it has to compile it's bytecode to machine code on multiple architectures. It's no different than webasm, just a different bytecode. A big advantage of webasm is that it's integrated into the existing javascript VM, that has already been sandboxed and battle hardened.

[eridius]

I believe that's PNaCl. NaCl just handles already-compiled machine code. But of course NaCl isn't portable, which is why PNaCl exists.

[nickpsecurity]

As in my other comment, something like that can be mathematically verified for correctness as well. That requires simplicity if one doesn't want to throw person-years of work at it w/ possibility of finding out it was impossible. My comment links to a formally-verified checker for NaCl as well.

https://news.ycombinator.com/item?id=14460649