diff --git a/src/lib/enr/keypair/secp256k1.ts b/src/lib/enr/keypair/secp256k1.ts
index a8aa47816c..251b0d7cab 100644
--- a/src/lib/enr/keypair/secp256k1.ts
+++ b/src/lib/enr/keypair/secp256k1.ts
@@ -1,8 +1,8 @@
-import crypto from "crypto";
-
 import * as secp256k1 from "secp256k1";
 import { concat } from "uint8arrays/concat";
 
+import { randomBytes } from "../../crypto";
+
 import { AbstractKeypair, IKeypair, IKeypairClass, KeypairType } from "./types";
 
 export function secp256k1PublicKeyToCompressed(
@@ -41,7 +41,7 @@ export const Secp256k1Keypair: IKeypairClass = class Secp256k1Keypair
   }
 
   static async generate(): Promise<Secp256k1Keypair> {
-    const privateKey = await randomBytes(32);
+    const privateKey = randomBytes(32);
     const publicKey = secp256k1.publicKeyCreate(privateKey);
     return new Secp256k1Keypair(privateKey, publicKey);
   }
@@ -69,13 +69,3 @@ export const Secp256k1Keypair: IKeypairClass = class Secp256k1Keypair
     return secp256k1.ecdsaVerify(sig, msg, this.publicKey);
   }
 };
-
-function randomBytes(length: number): Uint8Array {
-  if (typeof window !== "undefined" && window && window.crypto) {
-    const array = new Uint8Array(length);
-    window.crypto.getRandomValues(array);
-    return array;
-  } else {
-    return crypto.randomBytes(length);
-  }
-}
diff --git a/src/lib/enr/v4.ts b/src/lib/enr/v4.ts
index 0738a30732..0e70dc2640 100644
--- a/src/lib/enr/v4.ts
+++ b/src/lib/enr/v4.ts
@@ -1,8 +1,8 @@
-import crypto from "crypto";
-
 import { keccak256 } from "js-sha3";
 import * as secp256k1 from "secp256k1";
 
+import { randomBytes } from "../crypto";
+
 import { createNodeId } from "./create";
 import { NodeId } from "./types";
 
@@ -10,7 +10,7 @@ export function hash(input: Uint8Array): Uint8Array {
   return new Uint8Array(keccak256.arrayBuffer(input));
 }
 
-export async function createPrivateKey(): Promise<Uint8Array> {
+export function createPrivateKey(): Uint8Array {
   return randomBytes(32);
 }
 
@@ -45,13 +45,13 @@ export class ENRKeyPair {
     public readonly publicKey: Uint8Array
   ) {}
 
-  public static async create(privateKey?: Uint8Array): Promise<ENRKeyPair> {
+  public static create(privateKey?: Uint8Array): ENRKeyPair {
     if (privateKey) {
       if (!secp256k1.privateKeyVerify(privateKey)) {
         throw new Error("Invalid private key");
       }
     }
-    const _privateKey = privateKey || (await createPrivateKey());
+    const _privateKey = privateKey || createPrivateKey();
     const _publicKey = publicKey(_privateKey);
     const _nodeId = nodeId(_publicKey);
 
@@ -66,13 +66,3 @@ export class ENRKeyPair {
     return verify(this.publicKey, msg, sig);
   }
 }
-
-function randomBytes(length: number): Uint8Array {
-  if (typeof window !== "undefined" && window && window.crypto) {
-    const array = new Uint8Array(length);
-    window.crypto.getRandomValues(array);
-    return array;
-  } else {
-    return crypto.randomBytes(length);
-  }
-}
diff --git a/src/lib/waku_message/version_1.ts b/src/lib/waku_message/version_1.ts
index 535c232484..db4883ea4d 100644
--- a/src/lib/waku_message/version_1.ts
+++ b/src/lib/waku_message/version_1.ts
@@ -1,9 +1,9 @@
 import { Buffer } from "buffer";
-import * as crypto from "crypto";
 
 import { keccak256 } from "js-sha3";
 import * as secp256k1 from "secp256k1";
 
+import { randomBytes } from "../crypto";
 import { hexToBytes } from "../utils";
 
 import * as ecies from "./ecies";
@@ -258,13 +258,3 @@ function ecRecoverPubKey(messageHash: string, signature: Buffer): Uint8Array {
     false
   );
 }
-
-function randomBytes(length: number): Uint8Array {
-  if (typeof window !== "undefined" && window && window.crypto) {
-    const array = new Uint8Array(length);
-    window.crypto.getRandomValues(array);
-    return array;
-  } else {
-    return crypto.randomBytes(length);
-  }
-}