AirAssembly: a low-level language for zk-STARKs

zk-s[nt]arks
4

I’ve just released a new version of AirAssembly (v0.2). Notable changes include:

  1. A single AirAssembly module can now contain AIR for many computations. This will enable “library” modules which will export different types of computations (e.g. hash functions, signature verification etc.).
  2. It is now possible to define module-level functions to encapsulate common algebraic expressions. This makes code much more compact.
  3. AirAssembly specs now include initial support for “long-range” constraints - thought, the compiler/runtime doesn’t handle them yet.

Here is how AirAssembly module for MiMC computation looks like now:

(module
    (field prime 4194304001)
    (const $alpha scalar 3)
    (function $mimcRound
        (result vector 1)
        (param $state vector 1) (param $roundKey scalar)
        (add 
            (exp (load.param $state) (load.const $alpha))
            (load.param $roundKey)))
    (export mimc
        (registers 1) (constraints 1) (steps 1024)
        (static
            (cycle (prng sha256 0x4d694d43 64)))
        (init
            (param $seed vector 1)
            (load.param $seed))
        (transition
            (call $mimcRound (load.trace 0) (get (load.static 0) 0)))
        (evaluation
            (sub
                (load.trace 1)
                (call $mimcRound (load.trace 0) (get (load.static 0) 0))))))

genSTARK has also been updated to work with AirAssembly back-end, though, the changes haven’t been merged to the master yet (if anyone is curious, they are in this PR).

As always, any thoughts/feedback is welcome.