Implement UTF-8 safe Base64 encode/decode functions and update PolicyRequest class to use them

src/index.ts

-import { encode as base64Encode, decode as base64Decode } from 'base-64';
 import axios from 'axios';
 
 /**
@@ -81,6 +80,44 @@ async function getPublicIP(): Promise<string | null> {
     }
 }
 
+// UTF-8 safe Base64 encode/decode helpers (Node + browser)
+function base64EncodeUtf8(input: string): string {
+    try {
+        if (typeof Buffer !== 'undefined' && typeof Buffer.from === 'function') {
+            return Buffer.from(input, 'utf8').toString('base64');
+        }
+        const btoaFn = (globalThis as any).btoa;
+        if (typeof btoaFn === 'function') {
+            // encodeURIComponent -> percent-encode -> unescape to binary string
+            return btoaFn(unescape(encodeURIComponent(input)));
+        }
+    } catch (e) {
+        // fallthrough to throw below
+    }
+    throw new Error('No available method to perform base64 encoding');
+}
+
+function base64DecodeUtf8(b64: string): string {
+    try {
+        if (typeof Buffer !== 'undefined' && typeof Buffer.from === 'function') {
+            return Buffer.from(b64, 'base64').toString('utf8');
+        }
+        const atobFn = (globalThis as any).atob;
+        if (typeof atobFn === 'function') {
+            const binary = atobFn(b64);
+            // convert binary string to percent-encoded string, then decode
+            const percentEncoded = Array.prototype.map.call(binary, (ch: string) => {
+                const code = ch.charCodeAt(0).toString(16).toUpperCase();
+                return '%' + (code.length < 2 ? '0' + code : code);
+            }).join('');
+            return decodeURIComponent(percentEncoded);
+        }
+    } catch (e) {
+        // fallthrough to throw below
+    }
+    throw new Error('No available method to perform base64 decoding');
+}
+
 /**
  * Policy Request Instance Configuration
  */
@@ -179,7 +216,7 @@ export class PolicyRequest {
         };
 
         const jsonString = JSON.stringify(data);
-        return base64Encode(jsonString);
+        return base64EncodeUtf8(jsonString);
     }
 
     /**
@@ -217,7 +254,7 @@ export class PolicyRequest {
      */
     static decode(base64String: string): PolicyRequestData {
         try {
-            const decoded = base64Decode(base64String);
+            const decoded = base64DecodeUtf8(base64String);
             return JSON.parse(decoded);
         } catch (error) {
             throw new Error(