diff --git a/lib/sessionManager/stores/expoSecureStore.ts b/lib/sessionManager/stores/expoSecureStore.ts
index b387ab5..958b0e2 100644
--- a/lib/sessionManager/stores/expoSecureStore.ts
+++ b/lib/sessionManager/stores/expoSecureStore.ts
@@ -4,6 +4,14 @@ import { splitString } from "../utils.js";
 
 let expoSecureStore: typeof import("expo-secure-store") | undefined = undefined;
 
+async function waitForExpoSecureStore() {
+  let tries = 0;
+  while (!expoSecureStore && tries < 20) {
+    await new Promise((resolve) => setTimeout(resolve, 100));
+    tries++;
+  }
+}
+
 /**
  * Provides a expo local store based session manager implementation for the browser.
  * @class ExpoSecureStore
@@ -42,6 +50,7 @@ export class ExpoSecureStore<V = StorageKeys> implements SessionManager<V> {
     itemKey: V | StorageKeys,
     itemValue: unknown,
   ): Promise<void> {
+    await waitForExpoSecureStore();
     // clear items first
     await this.removeSessionItem(itemKey);
 
@@ -66,6 +75,8 @@ export class ExpoSecureStore<V = StorageKeys> implements SessionManager<V> {
    * @returns {unknown | null}
    */
   async getSessionItem(itemKey: V | StorageKeys): Promise<unknown | null> {
+    await waitForExpoSecureStore();
+
     const chunks = [];
     let index = 0;
 
@@ -82,7 +93,7 @@ export class ExpoSecureStore<V = StorageKeys> implements SessionManager<V> {
       );
     }
 
-    return chunks.join("");
+    return chunks.join("") || null;
   }
 
   /**
@@ -91,6 +102,8 @@ export class ExpoSecureStore<V = StorageKeys> implements SessionManager<V> {
    * @returns {void}
    */
   async removeSessionItem(itemKey: V | StorageKeys): Promise<void> {
+    await waitForExpoSecureStore();
+
     let index = 0;
 
     let chunk = await expoSecureStore!.getItemAsync(
diff --git a/lib/types.ts b/lib/types.ts
index cb177a2..8904ff0 100644
--- a/lib/types.ts
+++ b/lib/types.ts
@@ -105,6 +105,10 @@ export type LoginOptions = {
    * Whether to show the success screen at the end of the flow, this is most useful when the callback is not a webpage.
    */
   hasSuccessPage?: boolean;
+  /**
+   * Single use code to prevent replay attacks
+   */
+  nonce?: string;
 };
 
 export enum IssuerRouteTypes {
diff --git a/lib/utils/generateAuthUrl.ts b/lib/utils/generateAuthUrl.ts
index 257f5b2..4308709 100644
--- a/lib/utils/generateAuthUrl.ts
+++ b/lib/utils/generateAuthUrl.ts
@@ -22,11 +22,15 @@ export const generateAuthUrl = (
     ...mapLoginMethodParamsForUrl(options),
   };
 
-  const generatedState = generateRandomString(32);
-  const generatedNonce = generateRandomString(16);
+  if (!options.state) {
+    options.state = generateRandomString(32);
+  }
+  searchParams["state"] = options.state;
 
-  searchParams["state"] = options.state || generatedState;
-  searchParams["nonce"] = generatedNonce;
+  if (!options.nonce) {
+    options.nonce = generateRandomString(16);
+  }
+  searchParams["nonce"] = options.nonce;
 
   if (options.codeChallenge) {
     searchParams["code_challenge"] = options.codeChallenge;
@@ -38,5 +42,9 @@ export const generateAuthUrl = (
   }
 
   authUrl.search = new URLSearchParams(searchParams).toString();
-  return { url: authUrl, state: generatedState, nonce: generatedNonce };
+  return {
+    url: authUrl,
+    state: searchParams["state"],
+    nonce: searchParams["nonce"],
+  };
 };
diff --git a/lib/utils/generateRandomString.ts b/lib/utils/generateRandomString.ts
index 1d61668..183a4eb 100644
--- a/lib/utils/generateRandomString.ts
+++ b/lib/utils/generateRandomString.ts
@@ -4,11 +4,28 @@
  * @returns {string} required secret
  */
 export const generateRandomString = (length: number = 28): string => {
-  const arr = new Uint8Array(length / 2);
-  crypto.getRandomValues(arr);
-  return Array.from(arr, dec2hex).join("");
+  if (crypto) {
+    const arr = new Uint8Array(length / 2);
+    crypto.getRandomValues(arr);
+    return Array.from(arr, dec2hex).join("");
+  } else {
+    return generateRandomStringNonCrypto(length);
+  }
 };
 
 function dec2hex(dec: number) {
   return dec.toString(16).padStart(2, "0");
 }
+
+function generateRandomStringNonCrypto(length: number = 28) {
+  const characters =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
+  let result = "";
+  const charactersLength = characters.length;
+
+  for (let i = 0; i < length; i++) {
+    result += characters.charAt(Math.floor(Math.random() * charactersLength));
+  }
+
+  return result;
+}