From 35df009837adbf53fa0093bda3ce1aa4dd085c29 Mon Sep 17 00:00:00 2001
From: Artem Gureev <artguril@proton.me>
Date: Fri, 3 Jul 2026 14:03:53 +0000
Subject: [PATCH] feat(lee): add for_dummy nullifier and commitment derivations

---
 lee/state_machine/core/src/commitment.rs | 14 +++++++++++++-
 lee/state_machine/core/src/nullifier.rs  |  8 ++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/lee/state_machine/core/src/commitment.rs b/lee/state_machine/core/src/commitment.rs
index 92085d7d..79e73e7f 100644
--- a/lee/state_machine/core/src/commitment.rs
+++ b/lee/state_machine/core/src/commitment.rs
@@ -2,7 +2,10 @@ use borsh::{BorshDeserialize, BorshSerialize};
 use risc0_zkvm::sha::{Impl, Sha256 as _};
 use serde::{Deserialize, Serialize};
 
-use crate::account::{Account, AccountId};
+use crate::{
+    Nullifier,
+    account::{Account, AccountId},
+};
 
 /// A commitment to all zero data.
 /// ```python
@@ -78,6 +81,15 @@ impl Commitment {
         bytes.extend_from_slice(&account_bytes_with_hashed_data);
         Self(Impl::hash_bytes(&bytes).as_bytes().try_into().unwrap())
     }
+
+    #[must_use]
+    pub fn for_dummy(nullifier: &Nullifier, commitment_seed: &[u8; 32]) -> Self {
+        const DUMMY_PREFIX: &[u8; 32] = b"/LEE/v0.3/Commitment/Dummy/\x00\x00\x00\x00\x00";
+        let mut bytes = DUMMY_PREFIX.to_vec();
+        bytes.extend_from_slice(&nullifier.0);
+        bytes.extend_from_slice(commitment_seed);
+        Self(Impl::hash_bytes(&bytes).as_bytes().try_into().unwrap())
+    }
 }
 
 pub type CommitmentSetDigest = [u8; 32];
diff --git a/lee/state_machine/core/src/nullifier.rs b/lee/state_machine/core/src/nullifier.rs
index 0374a31a..b7f86289 100644
--- a/lee/state_machine/core/src/nullifier.rs
+++ b/lee/state_machine/core/src/nullifier.rs
@@ -109,6 +109,14 @@ impl Nullifier {
         bytes.extend_from_slice(account_id.value());
         Self(Impl::hash_bytes(&bytes).as_bytes().try_into().unwrap())
     }
+
+    #[must_use]
+    pub fn for_dummy(nullifier_seed: &[u8; 32]) -> Self {
+        const DUMMY_PREFIX: &[u8; 32] = b"/LEE/v0.3/Nullifier/Dummy/\x00\x00\x00\x00\x00\x00";
+        let mut bytes = DUMMY_PREFIX.to_vec();
+        bytes.extend_from_slice(nullifier_seed);
+        Self(Impl::hash_bytes(&bytes).as_bytes().try_into().unwrap())
+    }
 }
 
 #[cfg(test)]