feat(hash): add poseidon hash

crates/starknet-types-core/src/hash/mod.rs

@@ -1,5 +1,7 @@
 mod pedersen;
+mod poseidon;
 mod traits;
 
 pub use self::pedersen::*;
+pub use self::poseidon::*;
 pub use self::traits::*;

crates/starknet-types-core/src/hash/poseidon.rs

@@ -0,0 +1,58 @@
+use crate::felt::Felt;
+use lambdaworks_crypto::hash::poseidon::{
+    starknet::PoseidonCairoStark252, Poseidon as PoseidonLambdaworks,
+};
+use lambdaworks_math::field::{
+    element::FieldElement, fields::fft_friendly::stark_252_prime_field::Stark252PrimeField,
+};
+
+use super::traits::StarkHash;
+
+pub struct Poseidon;
+
+impl StarkHash for Poseidon {
+    /// Computes the Poseidon hash of two Felts, as defined
+    /// in <https://docs.starknet.io/documentation/architecture_and_concepts/Hashing/hash-functions/#poseidon_hash.>
+    fn hash(felt_0: &Felt, felt_1: &Felt) -> Felt {
+        Felt(PoseidonCairoStark252::hash(&felt_0.0, &felt_1.0))
+    }
+    /// Computes the Poseidon hash of an array of Felts, as defined
+    /// in <https://docs.starknet.io/documentation/architecture_and_concepts/Cryptography/hash-functions/#poseidon_array_hash.>
+    fn hash_array(felts: &[Felt]) -> Felt {
+        Felt(PoseidonCairoStark252::hash_many(unsafe {
+            core::mem::transmute::<&[Felt], &[FieldElement<Stark252PrimeField>]>(felts)
+        }))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_poseidon_hash() {
+        let x =
+            Felt::from_hex("0x03d937c035c878245caf64531a5756109c53068da139362728feb561405371cb")
+                .unwrap();
+        let y =
+            Felt::from_hex("0x0208a0a10250e382e1e4bbe2880906c2791bf6275695e02fbbc6aeff9cd8b31a")
+                .unwrap();
+
+        assert_eq!(
+            Poseidon::hash(&x, &y),
+            Felt::from_hex("0x67c6a2e2d0c7867f97444ae17956dbc89d40ad22255bb06f5f6c515958926ed")
+                .unwrap()
+        );
+    }
+
+    #[test]
+    fn test_pedersen_hash_array() {
+        let a = Felt::from_hex("0xaa").unwrap();
+        let b = Felt::from_hex("0xbb").unwrap();
+        let c = Felt::from_hex("0xcc").unwrap();
+        let expected =
+            Felt::from_hex("0x2742e049f7e1613e4a014efeec0d742882a798ae0af8b8dd730358c23848775")
+                .unwrap();
+        assert_eq!(Poseidon::hash_array(&[a, b, c]), expected);
+    }
+}