Add comprehensive Poseidon/Poseidon2 support for BN254 and BLS12-381

soroban-sdk/src/crypto.rs

@@ -14,8 +14,8 @@ pub(crate) mod poseidon_params;
 pub mod poseidon_sponge;
 pub(crate) mod utils;
 pub use bn254::Fr as BnScalar;
-pub use poseidon2_sponge::Poseidon2Sponge;
-pub use poseidon_sponge::PoseidonSponge;
+pub use poseidon2_sponge::{Poseidon2Config, Poseidon2Sponge};
+pub use poseidon_sponge::{PoseidonConfig, PoseidonSponge};
 
 /// A `BytesN<N>` generated by a cryptographic hash function.
 ///
@@ -199,26 +199,17 @@ impl Crypto {
         bn254::Bn254::new(self.env())
     }
 
-    /// Performs a Poseidon hash using a sponge construction
-    pub fn poseidon_hash(&self, inputs: &Vec<U256>, field: Symbol) -> U256 {
-        // The initial value for the capacity element initialized with 0 for standard Poseidon
-        let iv = U256::from_u32(&self.env, 0);
-        let mut sponge = PoseidonSponge::new(&self.env, iv, field);
-        for input in inputs.iter() {
-            sponge.absorb(input);
-        }
-        sponge.squeeze()
+    /// Performs a Poseidon hash using a sponge construction that matches circom's [implementation](https://github.com/iden3/circomlib/blob/35e54ea21da3e8762557234298dbb553c175ea8d/circuits/poseidon.circom)
+    pub fn poseidon_hash<const N: usize>(&self, field_type: Symbol, inputs: &[U256; N]) -> U256 {
+        let config = PoseidonConfig::new(&self.env, field_type, N as u32);
+        poseidon_sponge::hash(&self.env, inputs, config)
     }
 
-    /// Performs a poseidon2 hash with a sponge construction equivalent to the one in the Barretenberg proving system
-    pub fn poseidon2_hash(&self, inputs: &Vec<U256>, field: Symbol) -> U256 {
-        // The initial value for the capacity element initialized with `input.len() * 2^24` for Poseidon2
-        let iv = U256::from_u128(&self.env, (inputs.len() as u128) << 64);
-        let mut sponge = Poseidon2Sponge::new(&self.env, iv, field);
-        for input in inputs.iter() {
-            sponge.absorb(input);
-        }
-        sponge.squeeze()
+    /// Performs a poseidon2 hash with a sponge construction that matches noir's implementation.
+    /// Uses rate=3 (t=4) to match the noir/barretenberg [implementation](https://github.com/noir-lang/noir/blob/abfee1f54b20984172ba23482f4af160395cfba5/noir_stdlib/src/hash/poseidon2.nr).
+    pub fn poseidon2_hash<const N: usize>(&self, field_type: Symbol, inputs: &[U256; N]) -> U256 {
+        let config = Poseidon2Config::new(&self.env, field_type, 3);
+        poseidon2_sponge::hash(&self.env, inputs, config)
     }
 }