Basic multiplier example

Taken from Circom 2 tests

multiplier/Cargo.toml

@@ -6,4 +6,30 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+
+# WASM operations
+# wasmer = { version = "2.0" }
+# fnv = { version = "1.0.3", default-features = false }
+# num = { version = "0.4.0" }
+# num-traits = { version = "0.2.0", default-features = false }
+num-bigint = { version = "0.4", default-features = false, features = ["rand"] }
+
+# ZKP Generation
+# ark-ec = { version = "0.3.0", default-features = false, features = ["parallel"] }
+# ark-ff = { version = "0.3.0", default-features = false, features = ["parallel", "asm"] }
+ark-std = { version = "0.3.0", default-features = false, features = ["parallel"] }
+ark-bn254 = { version = "0.3.0" }
+ark-groth16 = { git = "https://github.com/arkworks-rs/groth16", rev = "765817f", features = ["parallel"] }
+# ark-poly = { version = "^0.3.0", default-features = false, features = ["parallel"] }
+# ark-relations = { version = "0.3.0", default-features = false }
+# ark-serialize = { version = "0.3.0", default-features = false }
+
 ark-circom = { git = "https://github.com/gakonst/ark-circom", features = ["circom-2"] }
+
+# error handling
+# thiserror = "1.0.26"
+color-eyre = "0.5"
+
+# decoding of data
+# hex = "0.4.3"
+# byteorder = "1.4.3"

multiplier/src/main.rs

@@ -1,3 +1,49 @@
+use ark_circom::{CircomBuilder, CircomConfig};
+use ark_std::rand::thread_rng;
+use color_eyre::Result;
+
+use ark_bn254::Bn254;
+use ark_groth16::{
+    create_random_proof as prove, generate_random_parameters, prepare_verifying_key, verify_proof,
+};
+
+fn groth16_proof_example() -> Result<()> {
+
+    let cfg = CircomConfig::<Bn254>::new(
+        "./resources/circom2_multiplier2.wasm",
+        "./resources/circom2_multiplier2.r1cs",
+    )?;
+
+    let mut builder = CircomBuilder::new(cfg);
+    builder.push_input("a", 3);
+    builder.push_input("b", 11);
+
+    // create an empty instance for setting it up
+    let circom = builder.setup();
+
+    let mut rng = thread_rng();
+    let params = generate_random_parameters::<Bn254, _, _>(circom, &mut rng)?;
+
+    let circom = builder.build()?;
+
+    let inputs = circom.get_public_inputs().unwrap();
+
+    let proof = prove(circom, &params, &mut rng)?;
+
+    let pvk = prepare_verifying_key(&params.vk);
+
+    let verified = verify_proof(&pvk, &proof, &inputs)?;
+
+    assert!(verified);
+
+    Ok(())
+}
+
 fn main() {
     println!("Hello, world!");
+
+    match groth16_proof_example() {
+        Ok(_) => println!("Success"),
+        Err(_) => println!("Error")
+    }
 }