diff --git a/packages/crypto/src/context.tsx b/packages/crypto/src/context.tsx
index 588aff1..7e701c5 100644
--- a/packages/crypto/src/context.tsx
+++ b/packages/crypto/src/context.tsx
@@ -76,11 +76,11 @@ export default function Provider(props: { children: React.ReactNode }) {
 
 /**
  * Creates crypto action functions that safely delegate to the worker API.
- * @param apiRef Worker API reference object.
+ * @param getApiRef Function that returns the worker API reference.
  * @returns Typed crypto action functions.
  */
 export function createCryptoActions(
-  apiRef: React.RefObject<ApiRef | null>,
+  getApiRef: () => ApiRef | null,
 ): CryptoContextType {
   /**
    * Encrypts plaintext by delegating to the crypto worker API.
@@ -92,7 +92,7 @@ export function createCryptoActions(
     secret: string,
     plaintext: string,
   ): Promise<string> => {
-    const api = apiRef.current;
+    const api = getApiRef();
     if (!api) throw new Error("API not initialized");
     return await api.encrypt(secret, plaintext);
   };
@@ -107,7 +107,7 @@ export function createCryptoActions(
     secret: string,
     ciphertext: string,
   ): Promise<string> => {
-    const api = apiRef.current;
+    const api = getApiRef();
     if (!api) throw new Error("API not initialized");
     return await api.decrypt(secret, ciphertext);
   };
@@ -124,7 +124,7 @@ export function createCryptoActions(
     ownPublicKey: string,
     otherPublicKey: string,
   ): Promise<string> => {
-    const api = apiRef.current;
+    const api = getApiRef();
     if (!api) throw new Error("API not initialized");
     return await api.getSharedSecret(
       ownPrivateKey,
diff --git a/packages/crypto/src/worker.test.ts b/packages/crypto/src/worker.test.ts
index 3d0020d..eae1c3c 100644
--- a/packages/crypto/src/worker.test.ts
+++ b/packages/crypto/src/worker.test.ts
@@ -8,8 +8,27 @@ import { decrypt, encrypt, getSharedSecret } from "./worker";
  * @returns Base64url string.
  */
 function bytesToB64u(value: Uint8Array): string {
-  const b64 = Buffer.from(value).toString("base64");
-  return b64.replace(/\+/g, "-").replace(/\//g, "_").replace(/=+$/g, "");
+  const alphabet =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+  let output = "";
+
+  for (let index = 0; index < value.length; index += 3) {
+    const first = value[index] ?? 0;
+    const second = value[index + 1] ?? 0;
+    const third = value[index + 2] ?? 0;
+    const chunk = (first << 16) | (second << 8) | third;
+
+    output += alphabet[(chunk >> 18) & 63];
+    output += alphabet[(chunk >> 12) & 63];
+    output += index + 1 < value.length ? alphabet[(chunk >> 6) & 63] : "=";
+    output += index + 2 < value.length ? alphabet[chunk & 63] : "=";
+  }
+
+  return output
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=+$/g, "");
 }
 
 /**