diff --git a/src/crypto-util/crypto-util.spec.ts b/src/crypto-util/crypto-util.spec.ts
index c3afc76..6a05fa1 100644
--- a/src/crypto-util/crypto-util.spec.ts
+++ b/src/crypto-util/crypto-util.spec.ts
@@ -22,6 +22,14 @@ describe('CryptoUtil', () => {
     });
   });
 
+  describe('createAesKey', () => {
+    it('should return a Uint8Array', async () => {
+      const result = await CryptoUtil.createAesKey(256);
+      expect(result).toBeInstanceOf(Uint8Array);
+      expect(result.length).toBe(32);
+    });
+  });
+
   describe('encodeBase64', () => {
     it('should accept string and return a base64 encoded string', () => {
       const result = CryptoUtil.encodeBase64('hello world');
diff --git a/src/crypto-util/crypto-util.ts b/src/crypto-util/crypto-util.ts
index 7c634b0..7b0b8e8 100644
--- a/src/crypto-util/crypto-util.ts
+++ b/src/crypto-util/crypto-util.ts
@@ -1,6 +1,13 @@
-// eslint-disable-next-line @typescript-eslint/ban-ts-comment
-// @ts-ignore
-const crypto: any = globalThis.crypto;
+import type { webcrypto } from 'crypto';
+
+declare global {
+  namespace globalThis {
+    // eslint-disable-next-line no-var
+    var crypto: typeof webcrypto;
+  }
+}
+
+const crypto = globalThis.crypto;
 
 export namespace CryptoUtil {
   export const sha256 = async (data: string | Uint8Array): Promise<Uint8Array> => {
@@ -14,6 +21,18 @@ export namespace CryptoUtil {
     return crypto.getRandomValues(new Uint8Array(bytes));
   };
 
+  export const createAesKey = async (length: 128 | 192 | 256): Promise<Uint8Array> => {
+    const key = await crypto.subtle.generateKey(
+      {
+        name: 'AES-GCM',
+        length: length,
+      },
+      true,
+      ['encrypt', 'decrypt']
+    );
+    return new Uint8Array(await crypto.subtle.exportKey('raw', key));
+  };
+
   export const encodeBase64 = (data: Uint8Array | string): string => {
     if (typeof data === 'string') {
       data = new TextEncoder().encode(data);