Poseidon hash

.gitignore

@@ -8,3 +8,5 @@ Cargo.lock
 
 # These are backup files generated by rustfmt
 **/*.rs.bk
+
+book/book

Cargo.toml

@@ -21,10 +21,13 @@ merlin = { version = "3.0", default-features = false }
 rand = "0.8.4"
 sha2 = "0.10.1"
 plonk-core = { git = "https://github.com/heliaxdev/ark-plonk/", features = ["trace"], branch="taiga/randomized-circuits" }
+plonk-hashing = { git = "https://github.com/heliaxdev/ark-plonk/", branch="taiga/randomized-circuits" }
 blake2 = "0.9"
 rs_merkle = { git = "https://github.com/heliaxdev/rs-merkle/" } # "0.2.2"
+lazy_static = "1"
 
-poseidon377 = { git = "https://github.com/penumbra-zone/poseidon377/" }
+[dev-dependencies]
+ark-std = "0.3"
 
 [patch.crates-io]
 ark-bls12-377 = { git="https://github.com/simonmasson/curves/", branch="new-curve-models" }

src/lib.rs

@@ -1,16 +1,22 @@
+use crate::poseidon::{
+    POSEIDON_HASH_PARAM_BLS12_377_SCALAR_ARITY2, POSEIDON_HASH_PARAM_BLS12_377_SCALAR_ARITY4,
+    WIDTH_3, WIDTH_5,
+};
 use ark_bls12_377::Fr as Fr377;
 use ark_ec::twisted_edwards_extended::GroupAffine as TEGroupAffine;
 use ark_ec::{AffineCurve, TEModelParameters};
 use ark_ff::*;
 use ark_serialize::CanonicalSerialize;
 use circuit::circuit_parameters::CircuitParameters;
+use plonk_hashing::poseidon::poseidon::{NativeSpec, Poseidon};
 use rs_merkle::{algorithms::Blake2s, Hasher, MerkleTree};
 use sha2::{Digest, Sha512};
 
 pub mod action;
 pub mod circuit;
 pub mod el_gamal;
 pub mod note;
+pub mod poseidon;
 pub mod token;
 pub mod transaction;
 pub mod user;
@@ -42,16 +48,49 @@ impl HashToField for Fr377 {
             .map(|elt| Fr377::from_le_bytes_mod_order(elt))
             .collect();
 
-        assert!(elts.len() <= 5);
+        // TODO: decide the length, support 4 for now.
+        assert!(elts.len() <= 4);
         match elts.len() {
-            1 => poseidon377::hash_1(&Fr377::zero(), elts[0]),
-            2 => poseidon377::hash_2(&Fr377::zero(), (elts[0], elts[1])),
-            3 => poseidon377::hash_3(&Fr377::zero(), (elts[0], elts[1], elts[2])),
-            4 => poseidon377::hash_4(&Fr377::zero(), (elts[0], elts[1], elts[2], elts[3])),
-            _ => poseidon377::hash_5(
-                &Fr377::zero(),
-                (elts[0], elts[1], elts[2], elts[3], elts[4]),
-            ),
+            1 => {
+                let mut poseidon = Poseidon::<(), NativeSpec<Fr377, WIDTH_3>, WIDTH_3>::new(
+                    &mut (),
+                    &POSEIDON_HASH_PARAM_BLS12_377_SCALAR_ARITY2,
+                );
+                poseidon.input(elts[0]).unwrap();
+                poseidon.input(Fr377::zero()).unwrap();
+                poseidon.output_hash(&mut ())
+            }
+            2 => {
+                let mut poseidon = Poseidon::<(), NativeSpec<Fr377, WIDTH_3>, WIDTH_3>::new(
+                    &mut (),
+                    &POSEIDON_HASH_PARAM_BLS12_377_SCALAR_ARITY2,
+                );
+                poseidon.input(elts[0]).unwrap();
+                poseidon.input(elts[1]).unwrap();
+                poseidon.output_hash(&mut ())
+            }
+            3 => {
+                let mut poseidon = Poseidon::<(), NativeSpec<Fr377, WIDTH_5>, WIDTH_5>::new(
+                    &mut (),
+                    &POSEIDON_HASH_PARAM_BLS12_377_SCALAR_ARITY4,
+                );
+                poseidon.input(elts[0]).unwrap();
+                poseidon.input(elts[1]).unwrap();
+                poseidon.input(elts[2]).unwrap();
+                poseidon.input(Fr377::zero()).unwrap();
+                poseidon.output_hash(&mut ())
+            }
+            _ => {
+                let mut poseidon = Poseidon::<(), NativeSpec<Fr377, WIDTH_5>, WIDTH_5>::new(
+                    &mut (),
+                    &POSEIDON_HASH_PARAM_BLS12_377_SCALAR_ARITY4,
+                );
+                poseidon.input(elts[0]).unwrap();
+                poseidon.input(elts[1]).unwrap();
+                poseidon.input(elts[2]).unwrap();
+                poseidon.input(elts[3]).unwrap();
+                poseidon.output_hash(&mut ())
+            }
         }
     }
 }

src/poseidon.rs

@@ -0,0 +1,68 @@
+use lazy_static::lazy_static;
+use plonk_hashing::poseidon::constants::PoseidonConstants;
+
+// ARITY: input number of hash
+// WIDTH_3 = ARITY + 1
+pub const WIDTH_3: usize = 3;
+pub const WIDTH_5: usize = 5;
+lazy_static! {
+    pub static ref POSEIDON_HASH_PARAM_BLS12_377_SCALAR_ARITY2: PoseidonConstants<ark_bls12_377::Fr> =
+        PoseidonConstants::generate::<WIDTH_3>();
+    pub static ref POSEIDON_HASH_PARAM_BLS12_377_SCALAR_ARITY4: PoseidonConstants<ark_bls12_377::Fr> =
+        PoseidonConstants::generate::<WIDTH_5>();
+
+    // Hashes of bls12_377::BaseField are generated automatically, not tested yet.
+    // Especially we need to check the round number generation from the paper.
+    pub static ref POSEIDON_HASH_PARAM_BLS12_377_BASE_ARITY2: PoseidonConstants<ark_bls12_377::Fq> =
+        PoseidonConstants::generate::<WIDTH_3>();
+    pub static ref POSEIDON_HASH_PARAM_BLS12_377_BASE_ARITY4: PoseidonConstants<ark_bls12_377::Fq> =
+        PoseidonConstants::generate::<WIDTH_5>();
+}
+
+#[test]
+fn test_poseidon_circuit_example() {
+    use ark_ec::PairingEngine;
+    use ark_std::{test_rng, UniformRand};
+    use plonk_hashing::poseidon::poseidon::{NativeSpec, PlonkSpec, Poseidon};
+    type E = ark_bls12_377::Bls12_377;
+    type P = ark_ed_on_bls12_377::EdwardsParameters;
+    type Fr = <E as PairingEngine>::Fr;
+    use plonk_core::constraint_system::StandardComposer;
+
+    let mut rng = test_rng();
+    let mut poseidon_native = Poseidon::<(), NativeSpec<Fr, WIDTH_3>, WIDTH_3>::new(
+        &mut (),
+        &POSEIDON_HASH_PARAM_BLS12_377_SCALAR_ARITY2,
+    );
+    let inputs = (0..(WIDTH_3 - 1))
+        .map(|_| Fr::rand(&mut rng))
+        .collect::<Vec<_>>();
+
+    inputs.iter().for_each(|x| {
+        let _ = poseidon_native.input(*x).unwrap();
+    });
+    let native_hash: Fr = poseidon_native.output_hash(&mut ());
+
+    let mut c = StandardComposer::<Fr, P>::new();
+    let inputs_var = inputs.iter().map(|x| c.add_input(*x)).collect::<Vec<_>>();
+    let mut poseidon_circuit = Poseidon::<_, PlonkSpec<WIDTH_3>, WIDTH_3>::new(
+        &mut c,
+        &POSEIDON_HASH_PARAM_BLS12_377_SCALAR_ARITY2,
+    );
+    inputs_var.iter().for_each(|x| {
+        let _ = poseidon_circuit.input(*x).unwrap();
+    });
+    let plonk_hash = poseidon_circuit.output_hash(&mut c);
+
+    c.check_circuit_satisfied();
+
+    let expected = c.add_input(native_hash);
+    c.assert_equal(expected, plonk_hash);
+
+    c.check_circuit_satisfied();
+    println!(
+        "circuit size for WIDTH_3 {} poseidon: {}",
+        WIDTH_3,
+        c.circuit_bound()
+    )
+}