diff --git a/packages/eddsa-poseidon/src/HashFunction.ts b/packages/eddsa-poseidon/src/HashFunction.ts
index 0135f1e3..f776d912 100644
--- a/packages/eddsa-poseidon/src/HashFunction.ts
+++ b/packages/eddsa-poseidon/src/HashFunction.ts
@@ -1,3 +1,5 @@
+import { Buffer } from "buffer"
+
 export interface HashFunction {
     update(data: Buffer): HashFunction
     digest(): Buffer