diff --git a/CHANGELOG.md b/CHANGELOG.md
index e4cd462010..fa40533c97 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 #### Changes
 - `FastProcessor` `restore_call_state()` and `restore_context()` now return `OperationError::Internal` instead of panicking on empty stacks ([#3371](https://github.com/0xMiden/miden-vm/pull/3371), fixes [#3296](https://github.com/0xMiden/miden-vm/issues/3296)).
 
+- Opened the `LargeSmtForest` backend API for external implementations: made `LineageMutation::new` and `AppliedLineageMutation::new` public and added `LineageId::as_bytes` and `MutationSet::from_parts`.
 - [BREAKING] Renamed module and kernel metadata APIs from `ModuleInfo`/`Kernel` to `ModuleDescriptor`/`KernelDescriptor`, including matching module descriptor method names ([#3356](https://github.com/0xMiden/miden-vm/pull/3356)).
 - Aligned workspace crate versions at `0.28.0`, except `midenc-hir-type`, so VM and crypto crates release as one version line.
 - Imported the Miden crypto crates, benches, fuzz targets, and Wycheproof tests into this workspace ([#3366](https://github.com/0xMiden/miden-vm/pull/3366)).
diff --git a/crates/crypto/src/merkle/smt/large_forest/root.rs b/crates/crypto/src/merkle/smt/large_forest/root.rs
index b928859201..e52e510ef3 100644
--- a/crates/crypto/src/merkle/smt/large_forest/root.rs
+++ b/crates/crypto/src/merkle/smt/large_forest/root.rs
@@ -37,6 +37,14 @@ impl LineageId {
     pub fn new(bytes: [u8; 32]) -> Self {
         Self(bytes)
     }
+
+    /// Returns the raw bytes of the lineage ID.
+    ///
+    /// This is primarily useful for [`Backend`](super::backend::Backend) implementations that
+    /// need to persist lineage identifiers.
+    pub fn as_bytes(&self) -> &[u8; 32] {
+        &self.0
+    }
 }
 
 impl core::fmt::Display for LineageId {
diff --git a/crates/crypto/src/merkle/smt/large_forest/utils.rs b/crates/crypto/src/merkle/smt/large_forest/utils.rs
index 130a447619..4d33761ea3 100644
--- a/crates/crypto/src/merkle/smt/large_forest/utils.rs
+++ b/crates/crypto/src/merkle/smt/large_forest/utils.rs
@@ -108,9 +108,10 @@ pub struct LineageMutation {
 impl LineageMutation {
     /// Constructs a lineage mutation.
     ///
-    /// This constructor is crate-private because callers must not be able to fabricate mutation
-    /// metadata that is inconsistent with the backend-prepared data in an [`SmtForestMutationSet`].
-    pub(crate) fn new(
+    /// This is intended for [`Backend`] implementations returning computed mutations. The
+    /// metadata must stay consistent with the backend-prepared data in the corresponding
+    /// [`SmtForestMutationSet`].
+    pub fn new(
         lineage: LineageId,
         old_version: Option<VersionId>,
         new_version: VersionId,
@@ -207,10 +208,10 @@ pub struct AppliedLineageMutation {
 impl AppliedLineageMutation {
     /// Constructs an applied lineage mutation.
     ///
-    /// This constructor is crate-private because backend implementations must keep the returned
-    /// history payload consistent with the prepared mutation data they just applied.
+    /// [`Backend`] implementations must keep the returned history payload consistent with the
+    /// prepared mutation data they just applied.
     #[allow(clippy::too_many_arguments)]
-    pub(crate) fn new(
+    pub fn new(
         lineage: LineageId,
         old_version: Option<VersionId>,
         new_version: VersionId,
diff --git a/crates/crypto/src/merkle/smt/mod.rs b/crates/crypto/src/merkle/smt/mod.rs
index 475f1c90fc..05616caa76 100644
--- a/crates/crypto/src/merkle/smt/mod.rs
+++ b/crates/crypto/src/merkle/smt/mod.rs
@@ -734,6 +734,29 @@ impl<const DEPTH: u8, K: Eq + Hash, V> MutationSet<DEPTH, K, V> {
             && self.new_pairs.is_empty()
             && self.old_root == self.new_root
     }
+
+    /// Creates a new mutation set from pre-computed components.
+    ///
+    /// This constructor performs no validation. The caller must ensure the components are
+    /// internally consistent, meaning that applying `node_mutations` and `new_pairs` to a tree
+    /// whose root is `old_root` yields a tree whose root is `new_root`. Intended for storage
+    /// backends that compute mutations from persisted tree data instead of an in-memory tree.
+    pub fn from_parts(
+        old_root: Word,
+        node_mutations: impl IntoIterator<Item = (NodeIndex, NodeMutation)>,
+        new_pairs: impl IntoIterator<Item = (K, V)>,
+        new_root: Word,
+    ) -> Self
+    where
+        K: Ord,
+    {
+        Self {
+            old_root,
+            node_mutations: node_mutations.into_iter().collect(),
+            new_pairs: new_pairs.into_iter().collect(),
+            new_root,
+        }
+    }
 }
 
 // SERIALIZATION