1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180

//! Specialised circuit for Poseidon where we have maximum degree 2 constraints.

pub mod columns;
pub mod interpreter;

#[cfg(test)]
mod tests {
    use crate::{
        poseidon_55_0_7_3_2::{columns::PoseidonColumn, interpreter, interpreter::PoseidonParams},
        poseidon_params_55_0_7_3,
        poseidon_params_55_0_7_3::PlonkSpongeConstantsIVC,
    };
    use ark_ff::{UniformRand, Zero};
    use kimchi_msm::{
        circuit_design::{ColAccessCap, ConstraintBuilderEnv, WitnessBuilderEnv},
        columns::ColumnIndexer,
        lookups::DummyLookupTable,
        Fp,
    };
    use mina_poseidon::permutation::poseidon_block_cipher;

    pub struct PoseidonBN254Parameters;

    pub const STATE_SIZE: usize = 3;
    pub const NB_FULL_ROUND: usize = 55;
    type TestPoseidonColumn = PoseidonColumn<STATE_SIZE, NB_FULL_ROUND>;
    pub const N_COL: usize = TestPoseidonColumn::N_COL;
    pub const N_DSEL: usize = 0;
    pub const N_FSEL: usize = 165;

    impl PoseidonParams<Fp, STATE_SIZE, NB_FULL_ROUND> for PoseidonBN254Parameters {
        fn constants(&self) -> [[Fp; STATE_SIZE]; NB_FULL_ROUND] {
            let rc = &poseidon_params_55_0_7_3::static_params().round_constants;
            std::array::from_fn(|i| std::array::from_fn(|j| Fp::from(rc[i][j])))
        }

        fn mds(&self) -> [[Fp; STATE_SIZE]; STATE_SIZE] {
            let mds = &poseidon_params_55_0_7_3::static_params().mds;
            std::array::from_fn(|i| std::array::from_fn(|j| Fp::from(mds[i][j])))
        }
    }

    type PoseidonWitnessBuilderEnv = WitnessBuilderEnv<
        Fp,
        TestPoseidonColumn,
        { <TestPoseidonColumn as ColumnIndexer>::N_COL },
        { <TestPoseidonColumn as ColumnIndexer>::N_COL },
        N_DSEL,
        N_FSEL,
        DummyLookupTable,
    >;

    #[test]
    /// Tests that poseidon circuit is correctly formed (witness
    /// generation + constraints match) and matches the CPU
    /// specification of Poseidon. Fast to run, can be used for
    /// debugging.
    pub fn test_poseidon_circuit() {
        let mut rng = o1_utils::tests::make_test_rng(None);
        let domain_size = 1 << 4;

        let mut witness_env: PoseidonWitnessBuilderEnv = WitnessBuilderEnv::create();

        // Write constants
        {
            let rc = PoseidonBN254Parameters.constants();
            rc.iter().enumerate().for_each(|(round, rcs)| {
                rcs.iter().enumerate().for_each(|(state_index, rc)| {
                    let rc = vec![*rc; domain_size];
                    witness_env.set_fixed_selector_cix(
                        PoseidonColumn::RoundConstant(round, state_index),
                        rc,
                    )
                });
            });
        }

        // Generate random inputs at each row
        for _row in 0..domain_size {
            let x: Fp = Fp::rand(&mut rng);
            let y: Fp = Fp::rand(&mut rng);
            let z: Fp = Fp::rand(&mut rng);

            interpreter::poseidon_circuit(&mut witness_env, &PoseidonBN254Parameters, [x, y, z]);

            // Check internal consistency of our circuit: that our
            // computed values match the CPU-spec implementation of
            // Poseidon.
            {
                let exp_output: Vec<Fp> = {
                    let mut state: Vec<Fp> = vec![x, y, z];
                    poseidon_block_cipher::<Fp, PlonkSpongeConstantsIVC>(
                        poseidon_params_55_0_7_3::static_params(),
                        &mut state,
                    );
                    state
                };
                let x_col: PoseidonColumn<STATE_SIZE, NB_FULL_ROUND> =
                    PoseidonColumn::Round(NB_FULL_ROUND - 1, 4);
                let y_col: PoseidonColumn<STATE_SIZE, NB_FULL_ROUND> =
                    PoseidonColumn::Round(NB_FULL_ROUND - 1, 9);
                let z_col: PoseidonColumn<STATE_SIZE, NB_FULL_ROUND> =
                    PoseidonColumn::Round(NB_FULL_ROUND - 1, 14);
                assert_eq!(witness_env.read_column(x_col), exp_output[0]);
                assert_eq!(witness_env.read_column(y_col), exp_output[1]);
                assert_eq!(witness_env.read_column(z_col), exp_output[2]);
            }

            witness_env.next_row();
        }
    }

    #[test]
    /// Checks that poseidon circuit can be proven and verified. Big domain.
    pub fn heavy_test_completeness() {
        let mut rng = o1_utils::tests::make_test_rng(None);
        let domain_size: usize = 1 << 15;

        let (relation_witness, fixed_selectors) = {
            let mut witness_env: PoseidonWitnessBuilderEnv = WitnessBuilderEnv::create();

            let mut fixed_selectors: [Vec<Fp>; N_FSEL] =
                std::array::from_fn(|_| vec![Fp::zero(); 1]);
            // Write constants
            {
                let rc = PoseidonBN254Parameters.constants();
                rc.iter().enumerate().for_each(|(round, rcs)| {
                    rcs.iter().enumerate().for_each(|(state_index, rc)| {
                        witness_env.set_fixed_selector_cix(
                            PoseidonColumn::RoundConstant(round, state_index),
                            vec![*rc; domain_size],
                        );
                        fixed_selectors[round * STATE_SIZE + state_index] = vec![*rc; domain_size];
                    });
                });
            }

            // Generate random inputs at each row
            for _row in 0..domain_size {
                let x: Fp = Fp::rand(&mut rng);
                let y: Fp = Fp::rand(&mut rng);
                let z: Fp = Fp::rand(&mut rng);

                interpreter::poseidon_circuit(
                    &mut witness_env,
                    &PoseidonBN254Parameters,
                    [x, y, z],
                );

                witness_env.next_row();
            }

            (
                witness_env.get_relation_witness(domain_size),
                fixed_selectors,
            )
        };

        let constraints = {
            let mut constraint_env = ConstraintBuilderEnv::<Fp, DummyLookupTable>::create();
            interpreter::apply_permutation(&mut constraint_env, &PoseidonBN254Parameters);
            let constraints = constraint_env.get_constraints();

            // We have 825 constraints in total
            assert_eq!(constraints.len(), 5 * STATE_SIZE * NB_FULL_ROUND);
            // Maximum degree of the constraints is 2
            assert_eq!(constraints.iter().map(|c| c.degree(1, 0)).max().unwrap(), 2);

            constraints
        };

        kimchi_msm::test::test_completeness_generic_no_lookups::<N_COL, N_COL, N_DSEL, N_FSEL, _>(
            constraints,
            Box::new(fixed_selectors),
            relation_witness,
            domain_size,
            &mut rng,
        );
    }
}