Introduction

Achronyme is a programming language for zero-knowledge circuits.

Write readable code. Decide what gets proven. Same language for general execution and ZK circuit compilation.

Quick Look

General-purpose execution

let make_counter = fn(init) {
    mut n = init
    return fn() { n = n + 1; return n }
}
let c = make_counter(0)
print(c())  // 1
print(c())  // 2

ZK circuit

circuit merkle_proof(root: Public, leaf: Witness, path: Witness[3], indices: Witness[3]) {
    merkle_verify(root, leaf, path, indices)
}

ach circuit merkle.ach --inputs "root=...,leaf=42,path_0=...,path_1=...,path_2=...,indices_0=0,indices_1=1,indices_2=0"
# → circuit.r1cs + witness.wtns (snarkjs-compatible)

Inline proof generation

let secret = 0p42
let hash = 0p17159...  // poseidon(42, 0)

let p = prove(hash: Public) {
    assert_eq(poseidon(secret, 0), hash)
}

print(proof_json(p))  // Groth16 proof, verifiable on-chain

How It Works

Achronyme has two execution modes from the same source:

VM mode (ach run) — Full language: closures, recursion, GC, arrays, maps, strings, I/O. Code runs like any scripting language.

Circuit mode (ach circuit) — Compiles to arithmetic constraints over BN254. No loops at runtime, no I/O — everything is unrolled and flattened into a constraint system for zero-knowledge proofs.

The prove block bridges both: it compiles its body as a circuit via ProveIR at compile time, captures variables from scope, and produces a cryptographic proof at runtime — all in one expression. Witnesses are auto-inferred; only public inputs need to be declared.

Source (.ach)
    │
    ├─► Parser (PEG) → AST
    │       │
    │       ├─► Bytecode → VM          (run mode)
    │       │
    │       └─► SSA IR → Optimize
    │               │
    │           ┌───┴───┐
    │           ▼       ▼
    │        R1CS    Plonkish
    │      (Groth16) (KZG-PlonK)
    │           │       │
    │           ▼       ▼
    │       .r1cs    Gates/Lookups
    │       .wtns    Copy constraints
    │           │       │
    │           └───┬───┘
    │               ▼
    │         Native proof
    │
    └─► prove { } → compile + witness + verify + proof (inline)

Status

• 2,543 unit tests + 162 E2E integration tests
• Cross-validated against snarkjs (independent constraint verification)
• 2 ZK backends: R1CS/Groth16 + Plonkish/KZG-PlonK
• Native in-process proof generation (no external tools)
• snarkjs-compatible binary export (Groth16 interoperability verified)
• 6 security audits resolved
• Poseidon hash compatible with circomlibjs (30% fewer constraints than Circom)