diff --git a/packages/common/mod.ts b/packages/common/mod.ts
index 71135bd0a..8f57c914b 100644
--- a/packages/common/mod.ts
+++ b/packages/common/mod.ts
@@ -30,6 +30,7 @@ export { SUITE_ID_HEADER_KEM } from "./src/interfaces/kemInterface.ts";
 export { EMPTY, INPUT_LENGTH_LIMIT, MINIMUM_PSK_LENGTH } from "./src/consts.ts";
 
 export {
+  base64UrlToBytes,
   concat,
   hexToBytes,
   i2Osp,
diff --git a/packages/dhkem-x25519/src/x25519.ts b/packages/dhkem-x25519/src/x25519.ts
index 52e7916be..206ab4a66 100644
--- a/packages/dhkem-x25519/src/x25519.ts
+++ b/packages/dhkem-x25519/src/x25519.ts
@@ -3,6 +3,7 @@ import { x25519 } from "@noble/curves/ed25519";
 import type { DhkemPrimitives, KdfInterface } from "@hpke/common";
 
 import {
+  base64UrlToBytes,
   DeriveKeyPairError,
   DeserializeError,
   EMPTY,
@@ -16,16 +17,6 @@ import {
 
 const ALG_NAME = "X25519";
 
-function base64UrlToBytes(v: string): Uint8Array {
-  const base64 = v.replace(/-/g, "+").replace(/_/g, "/");
-  const byteString = atob(base64);
-  const ret = new Uint8Array(byteString.length);
-  for (let i = 0; i < byteString.length; i++) {
-    ret[i] = byteString.charCodeAt(i);
-  }
-  return ret;
-}
-
 export class X25519 implements DhkemPrimitives {
   private _hkdf: KdfInterface;
   private _nPk: number;
diff --git a/packages/dhkem-x448/src/x448.ts b/packages/dhkem-x448/src/x448.ts
index b386eeede..b74503bfc 100644
--- a/packages/dhkem-x448/src/x448.ts
+++ b/packages/dhkem-x448/src/x448.ts
@@ -3,6 +3,7 @@ import { x448 } from "@noble/curves/ed448";
 import type { DhkemPrimitives, KdfInterface } from "@hpke/common";
 
 import {
+  base64UrlToBytes,
   DeriveKeyPairError,
   DeserializeError,
   EMPTY,
@@ -16,16 +17,6 @@ import {
 
 const ALG_NAME = "X448";
 
-function base64UrlToBytes(v: string): Uint8Array {
-  const base64 = v.replace(/-/g, "+").replace(/_/g, "/");
-  const byteString = atob(base64);
-  const ret = new Uint8Array(byteString.length);
-  for (let i = 0; i < byteString.length; i++) {
-    ret[i] = byteString.charCodeAt(i);
-  }
-  return ret;
-}
-
 export class X448 implements DhkemPrimitives {
   private _hkdf: KdfInterface;
   private _nPk: number;