diff --git a/src/keys.ts b/src/keys.ts
index e5f30ad..5650db7 100644
--- a/src/keys.ts
+++ b/src/keys.ts
@@ -2,6 +2,7 @@ import { blake3 } from "@noble/hashes/blake3";
 import { concatBytes } from "@noble/hashes/utils";
 import { hkdf } from "@noble/hashes/hkdf";
 import { sha256 } from "@noble/hashes/sha256";
+import { encodeEndian } from "@lumeweb/libs5";
 
 export function deriveChildKey(
   parentKey: Uint8Array,
@@ -18,3 +19,10 @@ export function deriveBlakeChildKey(
 
   return blake3(concatBytes(parentKey, tweakHash));
 }
+
+export function deriveBlakeChildKeyInt(
+  parentKey: Uint8Array,
+  tweak: number,
+): Uint8Array {
+  return blake3(concatBytes(parentKey, encodeEndian(tweak, 32)));
+}