Encrypting Genesys Cloud Web Messaging Guest Attributes Client-Side Using TypeScript

What You Will Build

• You will create a TypeScript module that encrypts custom guest attributes using the native Web Crypto API before transmitting them to Genesys Cloud.
• This solution uses the @genesyscloud/purecloud-embed SDK to inject encrypted data into the web messaging conversation context.
• The implementation covers TypeScript, browser-native cryptographic primitives, and Genesys Cloud OAuth token handling.

Prerequisites

• OAuth client type: Confidential client or Genesys Cloud Embedded Widget configuration
• Required scopes: webmessaging:guest:write, conversation:write
• SDK version: @genesyscloud/purecloud-embed@^2.0.0
• Language/runtime: TypeScript 5.0+, modern browser with Web Crypto API support (Chrome 67+, Firefox 62+, Safari 12+, Edge 79+)
• External dependencies: @types/node (for Buffer/Base64 utilities during build), @genesyscloud/purecloud-embed

Authentication Setup

Genesys Cloud Web Messaging relies on a session token issued during embed initialization. The embed SDK handles the underlying OAuth 2.0 Authorization Code Flow with PKCE automatically when you configure the oauth object. For deterministic key derivation, you will extract the raw JWT access token from the embed authentication state.

The following configuration establishes the embed and captures the session token. The token payload contains the sub (subject identifier) and aud (audience) claims, which provide stable entropy for key derivation.

import { Embed } from '@genesyscloud/purecloud-embed';

const EMBED_CONFIG = {
  org: {
    deploymentId: 'your-deployment-id',
    orgId: 'your-org-id'
  },
  oauth: {
    clientId: 'your-client-id',
    scope: 'webmessaging:guest:write conversation:write',
    grantType: 'authorization_code',
    redirectUri: 'https://your-app.com/oauth/callback'
  },
  messaging: {
    enabled: true,
    welcomeMessage: 'Welcome. Secure messaging enabled.'
  }
};

async function initializeEmbed(): Promise<{ embed: Embed; accessToken: string }> {
  const embed = await window.embed.init(EMBED_CONFIG);
  
  // Extract the raw JWT token from the embed's auth provider
  const authProvider = embed.getAuthProvider();
  const accessToken = await authProvider.getAccessToken();
  
  if (!accessToken) {
    throw new Error('Failed to retrieve OAuth access token from embed provider.');
  }
  
  return { embed, accessToken };
}

The getAccessToken() method returns the unencoded JWT string. You will pass this string directly into the cryptographic wrapper. The embed SDK manages token refresh cycles internally, so your key derivation function must be idempotent or tied to a specific token lifecycle. For this tutorial, you will derive a fresh encryption key each time the embed initializes or when a new conversation session begins.

Implementation

Step 1: Web Crypto Wrapper with AES-GCM and PBKDF2

The Web Crypto API provides SubtleCrypto for symmetric encryption. You will use PBKDF2 to stretch the JWT payload into a 256-bit AES key, then encrypt using AES-GCM for authenticated encryption. GCM prevents tampering and provides an authentication tag alongside the ciphertext.

interface CryptoResult {
  ciphertext: string; // Base64 encoded
  iv: string;         // Base64 encoded initialization vector
  authTag: string;    // GCM authentication tag (extracted from ciphertext in Web Crypto)
}

function arrayBufferToBase64(buffer: ArrayBuffer): string {
  const bytes = new Uint8Array(buffer);
  let binary = '';
  for (let i = 0; i < bytes.byteLength; i++) {
    binary += String.fromCharCode(bytes[i]);
  }
  return btoa(binary);
}

function base64ToArrayBuffer(base64: string): ArrayBuffer {
  const binary = atob(base64);
  const bytes = new Uint8Array(binary.length);
  for (let i = 0; i < binary.length; i++) {
    bytes[i] = binary.charCodeAt(i);
  }
  return bytes.buffer;
}

async function deriveKeyFromToken(token: string, salt: Uint8Array): Promise<CryptoKey> {
  // Extract JWT payload (second segment) for deterministic key material
  const payloadBase64 = token.split('.')[1];
  const payloadBytes = base64ToArrayBuffer(payloadBase64);
  
  const keyMaterial = await crypto.subtle.importKey(
    'raw',
    payloadBytes,
    'PBKDF2',
    false,
    ['deriveKey']
  );
  
  return crypto.subtle.deriveKey(
    {
      name: 'PBKDF2',
      salt: salt,
      iterations: 100000,
      hash: 'SHA-256'
    },
    keyMaterial,
    { name: 'AES-GCM', length: 256 },
    false,
    ['encrypt', 'decrypt']
  );
}

PBKDF2 with 100,000 iterations mitigates brute-force attacks against the derived key. The salt must be consistent across client and server if decryption occurs later. You will generate a static salt from your Genesys Cloud organization ID to ensure deterministic key derivation across sessions.

Step 2: Encrypt Guest Attributes and Handle Rate Limits

Guest attributes are JSON objects containing custom key-value pairs. You will serialize the attributes, encrypt them, and attach the initialization vector and ciphertext to the payload. Genesys Cloud APIs enforce strict rate limits. You will wrap the SDK attribute update call with exponential backoff retry logic for HTTP 429 responses.

interface GuestAttributes {
  [key: string]: string | number | boolean;
}

async function encryptAttributes(attributes: GuestAttributes, token: string, orgId: string): Promise<string> {
  // Deterministic salt from orgId
  const saltString = `genesys-salt-${orgId}`;
  const encoder = new TextEncoder();
  const salt = encoder.encode(saltString);
  
  const key = await deriveKeyFromToken(token, salt);
  
  // Generate random 12-byte IV for AES-GCM
  const iv = crypto.getRandomValues(new Uint8Array(12));
  
  const plaintext = encoder.encode(JSON.stringify(attributes));
  
  const encryptedBuffer = await crypto.subtle.encrypt(
    {
      name: 'AES-GCM',
      iv: iv
    },
    key,
    plaintext
  );
  
  // Pack IV and ciphertext into a single base64 string for conversation context
  const ivBase64 = arrayBufferToBase64(iv.buffer);
  const ciphertextBase64 = arrayBufferToBase64(encryptedBuffer);
  
  // Format: iv:ciphertext
  return `${ivBase64}:${ciphertextBase64}`;
}

async function retryOnRateLimit<T>(
  operation: () => Promise<T>,
  maxRetries: number = 3,
  baseDelay: number = 1000
): Promise<T> {
  let attempt = 0;
  while (true) {
    try {
      return await operation();
    } catch (error: any) {
      // Check for 429 Too Many Requests from Genesys Cloud
      const status = error?.status || error?.statusCode || error?.response?.status;
      if (status === 429 && attempt < maxRetries) {
        const retryAfter = error?.response?.headers?.['retry-after'];
        const delay = retryAfter ? parseInt(retryAfter, 10) * 1000 : baseDelay * Math.pow(2, attempt);
        console.warn(`Rate limit hit. Retrying in ${delay}ms...`);
        await new Promise(resolve => setTimeout(resolve, delay));
        attempt++;
      } else {
        throw error;
      }
    }
  }
}

The retryOnRateLimit utility intercepts SDK rejections. Genesys Cloud returns a Retry-After header on 429 responses. The function parses this header and falls back to exponential backoff when the header is absent. This prevents cascading failures during high-volume web messaging traffic.

Step 3: Inject Encrypted Blobs into Conversation Context

The embed SDK exposes setAttributes() and updateAttributes() methods. You will encrypt the guest attributes, then inject them as a single string attribute named encrypted_guest_context. The Genesys Cloud web messaging platform stores custom attributes as strings, so the base64-encoded blob integrates seamlessly.

import { Embed } from '@genesyscloud/purecloud-embed';

async function injectEncryptedAttributes(embed: Embed, token: string, orgId: string, attributes: GuestAttributes): Promise<void> {
  const encryptedBlob = await encryptAttributes(attributes, token, orgId);
  
  const payload = {
    encrypted_guest_context: encryptedBlob,
    encryption_version: '1.0',
    encryption_algorithm: 'AES-GCM-PBKDF2'
  };
  
  await retryOnRateLimit(async () => {
    // setAttributes merges with existing attributes
    await embed.setAttributes(payload);
  });
  
  console.log('Encrypted guest attributes successfully injected into conversation context.');
}

The setAttributes method maps directly to the /api/v2/webmessaging/guests/{guestId}/attributes endpoint. Genesys Cloud validates attribute names against a whitelist. Custom attributes must follow the encrypted_guest_context naming convention or be pre-registered in the Genesys Cloud admin console under Web Messaging > Guest Attributes. The SDK handles the underlying POST request, header injection, and response parsing.

Complete Working Example

The following module combines authentication, cryptographic derivation, encryption, and SDK injection into a single executable flow. Replace the placeholder configuration values with your deployment credentials.

import { Embed } from '@genesyscloud/purecloud-embed';

// Configuration
const CONFIG = {
  deploymentId: 'your-deployment-id',
  orgId: 'your-org-id',
  clientId: 'your-client-id',
  redirectUri: 'https://your-app.com/oauth/callback'
};

// Crypto Utilities
function arrayBufferToBase64(buffer: ArrayBuffer): string {
  const bytes = new Uint8Array(buffer);
  let binary = '';
  for (let i = 0; i < bytes.byteLength; i++) {
    binary += String.fromCharCode(bytes[i]);
  }
  return btoa(binary);
}

function base64ToArrayBuffer(base64: string): ArrayBuffer {
  const binary = atob(base64);
  const bytes = new Uint8Array(binary.length);
  for (let i = 0; i < binary.length; i++) {
    bytes[i] = binary.charCodeAt(i);
  }
  return bytes.buffer;
}

async function deriveKeyFromToken(token: string, salt: Uint8Array): Promise<CryptoKey> {
  const payloadBase64 = token.split('.')[1];
  const payloadBytes = base64ToArrayBuffer(payloadBase64);
  
  const keyMaterial = await crypto.subtle.importKey(
    'raw',
    payloadBytes,
    'PBKDF2',
    false,
    ['deriveKey']
  );
  
  return crypto.subtle.deriveKey(
    { name: 'PBKDF2', salt, iterations: 100000, hash: 'SHA-256' },
    keyMaterial,
    { name: 'AES-GCM', length: 256 },
    false,
    ['encrypt', 'decrypt']
  );
}

async function encryptAttributes(attributes: Record<string, any>, token: string, orgId: string): Promise<string> {
  const saltString = `genesys-salt-${orgId}`;
  const salt = new TextEncoder().encode(saltString);
  const key = await deriveKeyFromToken(token, salt);
  
  const iv = crypto.getRandomValues(new Uint8Array(12));
  const plaintext = new TextEncoder().encode(JSON.stringify(attributes));
  
  const encryptedBuffer = await crypto.subtle.encrypt(
    { name: 'AES-GCM', iv },
    key,
    plaintext
  );
  
  const ivB64 = arrayBufferToBase64(iv.buffer);
  const ctB64 = arrayBufferToBase64(encryptedBuffer);
  return `${ivB64}:${ctB64}`;
}

async function retryOnRateLimit<T>(operation: () => Promise<T>, maxRetries: number = 3, baseDelay: number = 1000): Promise<T> {
  let attempt = 0;
  while (true) {
    try {
      return await operation();
    } catch (error: any) {
      const status = error?.status || error?.statusCode || error?.response?.status;
      if (status === 429 && attempt < maxRetries) {
        const retryAfter = error?.response?.headers?.['retry-after'];
        const delay = retryAfter ? parseInt(retryAfter, 10) * 1000 : baseDelay * Math.pow(2, attempt);
        console.warn(`Rate limit 429. Retrying in ${delay}ms...`);
        await new Promise(resolve => setTimeout(resolve, delay));
        attempt++;
      } else {
        throw error;
      }
    }
  }
}

// Main Execution
async function runSecureGuestAttributes(): Promise<void> {
  try {
    const embed = await window.embed.init({
      org: { deploymentId: CONFIG.deploymentId, orgId: CONFIG.orgId },
      oauth: { clientId: CONFIG.clientId, scope: 'webmessaging:guest:write', grantType: 'authorization_code', redirectUri: CONFIG.redirectUri },
      messaging: { enabled: true }
    });
    
    const authProvider = embed.getAuthProvider();
    const accessToken = await authProvider.getAccessToken();
    if (!accessToken) throw new Error('Missing access token');
    
    const guestData = {
      sessionId: 'sess_8f3a2b1c',
      userTier: 'premium',
      consentGiven: true,
      deviceFingerprint: 'fp_9x7k2m4p'
    };
    
    const encryptedBlob = await encryptAttributes(guestData, accessToken, CONFIG.orgId);
    
    await retryOnRateLimit(async () => {
      await embed.setAttributes({
        encrypted_guest_context: encryptedBlob,
        encryption_version: '1.0',
        encryption_algorithm: 'AES-GCM-PBKDF2'
      });
    });
    
    console.log('Encrypted attributes injected successfully.');
  } catch (err) {
    console.error('Failed to initialize secure guest attributes:', err);
  }
}

// Expose for browser execution
if (typeof window !== 'undefined') {
  (window as any).runSecureGuestAttributes = runSecureGuestAttributes;
}

This script initializes the embed, extracts the OAuth token, derives a deterministic key, encrypts the guest payload, and pushes the base64 blob into the conversation context. The retry wrapper protects against Genesys Cloud rate limiting during peak traffic.

Common Errors & Debugging

Error: OperationError: Unable to find algorithm AES-GCM

• Cause: The browser does not support Web Crypto API or the page is served over HTTP instead of HTTPS. Web Crypto requires a secure context.
• Fix: Serve the application over HTTPS. Verify browser compatibility. Add a fallback check: if (!window.crypto?.subtle) throw new Error('Secure context required.');

Error: 401 Unauthorized or 403 Forbidden

• Cause: The OAuth token lacks the webmessaging:guest:write scope, or the embed configuration uses an invalid clientId.
• Fix: Verify the client credentials in the Genesys Cloud admin console. Ensure the scope string in the embed configuration matches exactly. Check that the deployment ID matches the configured widget.

Error: 429 Too Many Requests

• Cause: Excessive calls to setAttributes within a short timeframe. Genesys Cloud enforces per-tenant and per-endpoint rate limits.
• Fix: The provided retryOnRateLimit function handles this automatically. Ensure you do not call setAttributes synchronously in a loop. Batch attribute updates and debounce user-triggered changes.

Error: DOMException: The operation failed for an reason related to the security policy of the user agent

• Cause: The IV length does not match the algorithm requirement. AES-GCM requires exactly 12 bytes (96 bits) for the initialization vector.
• Fix: Verify crypto.getRandomValues(new Uint8Array(12)) is used. Do not truncate or pad the IV. The Web Crypto API strictly enforces cryptographic parameter sizes.

Official References

• Genesys Cloud Web Messaging Guest Attributes API
• Genesys Cloud Embed SDK Documentation
• Web Crypto API Specification
• OAuth 2.0 Token Scopes for Web Messaging