fix: groth16 verifier B component EIP-197 G2 encoding

Makefile

@@ -0,0 +1,157 @@
+#
+# snarkjs — zkSNARKs in JavaScript (Groth16, PLONK, FFLONK)
+#
+# Node.js / circom / Foundry-based development, test, and build.
+#
+
+SHELL		= /bin/bash
+
+# ── Top-level targets ─────────────────────────────────────────────────
+
+.PHONY: all install build test test-smart-contracts test-forge test-all clean
+.PHONY: circuits circuit-groth16 circuit-circuit2 circuit-plonk circuit-fflonk
+.PHONY: verifier-preview
+.PHONY: print-%
+
+all:			install build test
+
+install:
+	npm install --no-audit --no-fund --loglevel=error
+	cd smart_contract_tests && npm install --no-audit --no-fund --loglevel=error
+
+build:
+	npm run build
+
+# ── Tests ─────────────────────────────────────────────────────────────
+
+# Unit / integration tests (mocha).  Covers:
+#   - Powers of Tau ceremony (full process)
+#   - Groth16 prove + off-chain verify
+#   - PLONK prove + off-chain verify
+#   - FFLONK prove + off-chain verify
+#   - Polynomial operations
+#   - Keypair derivation
+test:
+	npm test
+
+# Run a single mocha test file or grep pattern.
+#   make test-file FILE=test/fullprocess.js
+#   make test-grep GREP="Groth16 smart contract"
+test-file:
+	npx mocha $(FILE)
+
+test-grep:
+	npx mocha --grep "$(GREP)"
+
+# Smart-contract (Hardhat) tests.  Generates a Groth16 zkey from scratch,
+# exports a Solidity verifier, compiles + deploys it via Hardhat, and
+# calls verifyProof() on-chain.  This is the test that validates EIP-197
+# G2 encoding is correct end-to-end.
+test-smart-contracts:
+	cd smart_contract_tests && npm test
+
+# ── Forge (Foundry) EVM verification test ──────────────────────────────
+#
+# Lightweight on-chain verification test using Forge's built-in revm EVM
+# — the SAME precompile engine that rejected the faulty G2 encoding.
+#
+# Auto-skips with exit code 0 if Forge is not installed.  No npm deps
+# beyond snarkjs itself (no Hardhat, no ethers, no waffle).  A single
+# static Foundry binary is the only external requirement.
+#
+#   make test-forge                  # 1-input circuit (test/groth16)
+#   make test-forge-all              # both 1-input and 3-input circuits
+#   make nix-test-forge              # inside Nix environment
+#
+# Override circuit / ptau:
+#   make test-forge CIRCUIT_DIR=test/circuit2
+
+test-forge:
+	bash scripts/forge_verify_test.sh
+
+test-forge-all:
+	CIRCUIT_DIR=test/groth16   bash scripts/forge_verify_test.sh
+	CIRCUIT_DIR=test/circuit2  bash scripts/forge_verify_test.sh
+
+# Run ALL tests: off-chain unit tests + on-chain smart-contract tests.
+test-all:		test test-smart-contracts
+
+# ── Test circuits (circom → R1CS / WASM) ──────────────────────────────
+
+# Most test circuits are checked in pre-compiled.  Use these targets to
+# recompile them after editing a .circom file.
+#
+#   make circuits          # recompile all test circuits
+#   make circuit-groth16   # recompile only the groth16 1-input circuit
+
+CIRCUITS_DIR	= test
+CIRCOM		= circom
+CIRCOM_OPTS	= --r1cs --wasm --sym
+
+circuits:		circuit-groth16 circuit-circuit2 circuit-plonk circuit-fflonk
+
+circuit-groth16:
+	$(CIRCOM) $(CIRCOM_OPTS) $(CIRCUITS_DIR)/groth16/circuit.circom -o $(CIRCUITS_DIR)/groth16
+
+circuit-circuit2:
+	$(CIRCOM) $(CIRCOM_OPTS) $(CIRCUITS_DIR)/circuit2/circuit.circom -o $(CIRCUITS_DIR)/circuit2
+
+circuit-plonk:
+	$(CIRCOM) $(CIRCOM_OPTS) $(CIRCUITS_DIR)/plonk_circuit/circuit.circom -o $(CIRCUITS_DIR)/plonk_circuit
+
+circuit-fflonk:
+	$(CIRCOM) $(CIRCOM_OPTS) $(CIRCUITS_DIR)/fflonk/circuit.circom -o $(CIRCUITS_DIR)/fflonk
+
+# ── Verifier template checks ──────────────────────────────────────────
+
+# Dry-run: generate a Groth16 verifier from the template + a zkey and
+# print it to stdout.  Useful for inspecting the EIP-197 G2 encoding.
+#
+# Requires: make install (for snarkjs CLI), a compiled circuit, and a
+# ptau file (use test/plonk_circuit/powersOfTau15_final.ptau).
+#
+#   make verifier-preview
+PTAU_FILE	?= test/plonk_circuit/powersOfTau15_final.ptau
+R1CS_FILE	?= test/groth16/circuit.r1cs
+
+verifier-preview:
+	@snarkjs zkey new $(R1CS_FILE) $(PTAU_FILE) /tmp/verifier_preview.zkey 2>/dev/null
+	@snarkjs zkey export solidityverifier /tmp/verifier_preview.zkey /tmp/verifier_preview.sol 2>/dev/null
+	@cat /tmp/verifier_preview.sol
+	@rm -f /tmp/verifier_preview.zkey /tmp/verifier_preview.sol
+
+# ── Cleanup ───────────────────────────────────────────────────────────
+
+clean:
+	rm -rf build cache
+	rm -rf smart_contract_tests/artifacts smart_contract_tests/cache smart_contract_tests/contracts
+
+distclean:		clean
+	rm -rf node_modules smart_contract_tests/node_modules
+
+#
+# nix-...:
+#
+# Use a Nix flake environment to execute the make target, e.g.:
+#
+#     make nix-test
+#     make nix-test-smart-contracts
+#     make nix-test-all
+#
+nix-%:
+	@if [ -n "$(TARGET)" ]; then \
+		nix develop .#$(TARGET) $(NIX_OPTS) --command make $*; \
+	else \
+		nix develop $(NIX_OPTS) --command make $*; \
+	fi
+
+#
+# Target to allow the printing of 'make' variables, e.g.:
+#
+#     make print-PTAU_FILE
+#
+print-%:
+	@echo $* = "'$($*)'"
+	@echo $*\'s origin is $(origin $*)
+
+FORCE:

README.md

@@ -649,6 +649,63 @@ await wtnsCalculate(input, wasmFile, wtns, {memorySize: 0});
 
 
 
+## Development
+
+To work on snarkjs itself:
+
+```sh
+git clone https://github.com/iden3/snarkjs.git
+cd snarkjs
+npm install
+```
+
+### Run tests
+
+**Unit & integration tests** (off-chain proving/verifying):
+
+```sh
+npm test                      # mocha: powers of tau, groth16, plonk, fflonk, polynomials
+```
+
+**Smart-contract tests** (on-chain verification via Hardhat):
+
+```sh
+cd smart_contract_tests && npm install && npm test
+```
+
+### Forge-based on-chain verification (lightweight, auto-skips)
+
+A minimal Foundry-based test that validates exported Groth16 verifiers
+against a real EVM precompile engine (revm).  No Hardhat, no ethers —
+just a single `forge` binary.  If Foundry isn't installed the test
+prints `SKIP` and exits cleanly.
+
+```sh
+make test-forge               # 1-input circuit
+make test-forge-all           # both 1-input and 3-input circuits
+```
+
+Install Foundry:
+
+```sh
+curl -L https://foundry.paradigm.xyz | bash
+foundryup
+```
+
+### Nix flake (reproducible dev environment)
+
+A `flake.nix` provides `node`, `circom`, `forge`, `solc`, and all npm
+dependencies in a single shell:
+
+```sh
+nix develop                   # enter the dev shell
+make nix-test                 # run unit tests
+make nix-test-forge           # run forge EVM verification
+make nix-test-smart-contracts # run Hardhat on-chain tests
+```
+
+All `make nix-<target>` commands delegate to `nix develop --command make <target>`.
+
 ## Further resources
 - [Announcing the Perpetual Powers of Tau Ceremony to benefit all zk-SNARK projects](https://medium.com/coinmonks/announcing-the-perpetual-powers-of-tau-ceremony-to-benefit-all-zk-snark-projects-c3da86af8377)
 - [Scalable Multi-party Computation for zk-SNARK Parameters in

flake.nix

@@ -0,0 +1,80 @@
+{
+  description = "snarkjs — zkSNARKs implementation in JavaScript (Groth16/PLONK/FFLONK)";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-26.05";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+
+        commonInputs = with pkgs; [
+          # Core tools
+          cacert
+          git
+          gnumake
+          gnused
+          bash
+          bash-completion
+          which
+          jq
+          curl
+          gh
+
+          # Node.js — runtime and build tool
+          nodejs_22
+
+          # circom — compile .circom test circuits → R1CS / WASM
+          circom
+
+          # Foundry — forge (compiler/test), anvil (local node), cast (CLI)
+          # Provides solc for Hardhat-based smart-contract tests
+          foundry
+
+          # Standalone solc — for IDE/LSP support; Hardhat + Foundry also bundle solc
+          solc
+        ];
+      in {
+        devShells.default = pkgs.mkShell {
+          buildInputs = commonInputs;
+          shellHook = ''
+            export SOLC_PATH="${pkgs.solc}/bin/solc"
+
+            echo "snarkjs — zkSNARKs Development Environment"
+            echo ""
+            printf "  %-12s %s\n" "node"   "$(node --version 2>/dev/null)"
+            printf "  %-12s %s\n" "circom"  "$(circom --version 2>/dev/null | head -1)"
+            printf "  %-12s %s\n" "forge"   "$(forge --version 2>/dev/null | head -1)"
+            printf "  %-12s %s\n" "cast"    "$(cast --version 2>/dev/null | head -1)"
+            printf "  %-12s %s\n" "solc"    "$(solc --version 2>/dev/null | tail -1)"
+            printf "  %-12s %s\n" "gh"      "$(gh --version 2>/dev/null | head -1)"
+
+            # Install root npm deps (snarkjs build deps: rollup, mocha, etc.)
+            if [ ! -d node_modules ] && [ -f package.json ]; then
+              echo ""
+              echo "[flake] installing root npm dev deps ..."
+              npm install --no-audit --no-fund --loglevel=error
+            fi
+
+            # Install smart-contract test deps (hardhat, ethers, chai, etc.)
+            if [ -f smart_contract_tests/package.json ] && [ ! -d smart_contract_tests/node_modules ]; then
+              echo ""
+              echo "[flake] installing smart-contract test npm deps ..."
+              ( cd smart_contract_tests && npm install --no-audit --no-fund --loglevel=error )
+            fi
+
+            # Prepend local node_modules/.bin so snarkjs CLI is on PATH
+            if [ -x node_modules/.bin/snarkjs ]; then
+              export PATH="$PWD/node_modules/.bin:$PATH"
+              printf "  %-12s %s\n" "snarkjs" "$(snarkjs --version 2>/dev/null || echo 'installed')"
+            fi
+
+            echo ""
+            echo "Commands:  make all | make test | make test-forge | make nix-test-forge | make build"
+          '';
+        };
+      });
+}

forge_test/.gitignore

@@ -0,0 +1,6 @@
+# Generated files from forge verify test
+src/
+test/
+out/
+cache/
+lib/

forge_test/foundry.lock

@@ -0,0 +1,8 @@
+{
+  "lib/forge-std": {
+    "tag": {
+      "name": "v1.16.1",
+      "rev": "620536fa5277db4e3fd46772d5cbc1ea0696fb43"
+    }
+  }
+}

forge_test/foundry.toml

@@ -0,0 +1,13 @@
+[profile.default]
+  src = "src"
+  out = "out"
+  libs = ["lib"]
+  test = "test"
+  solc = "0.8.17"
+  evm_version = "istanbul"
+  optimizer = true
+  optimizer_runs = 999999
+
+# The Groth16 verifier uses inline assembly (bn256Pairing precompile
+# at addresses 6, 7, 8).  These precompiles are available on all
+# post-Byzantium EVMs; Istanbul is a safe default for revm/anvil.