Filtering Sensitive Data in NICE CXone Agent Assist Transcripts with Java

What You Will Build

• This service intercepts real-time Agent Assist speech-to-text streams, detects credit card numbers and Social Security Numbers using regular expressions, replaces matched patterns with asterisks, and patches the updated transcript back to the CXone Assist API.
• The implementation uses the NICE CXone v2 Assist API, the official CXone Java SDK for REST operations, and Java 11 native WebSocket and HTTP client libraries for stream interception and audit logging.
• The tutorial covers Java 11+ with Maven dependencies, demonstrating production-grade error handling, OAuth token management, exponential backoff for rate limits, and SHA-256 cryptographic hashing for compliance audit trails.

Prerequisites

• OAuth 2.0 Client Credentials grant type with scopes: assist:read, assist:write, conversation:read
• CXone API version: v2
• Java runtime: 11 or higher
• Maven dependencies:
  • com.nice.ic:nice-cxone-java-sdk:2.0.0 (or latest stable)
  • com.google.code.gson:gson:2.10.1 for JSON serialization
• Environment variables: CXONE_ENVIRONMENT, CXONE_CLIENT_ID, CXONE_CLIENT_SECRET, CXONE_SESSION_ID

Authentication Setup

CXone requires OAuth 2.0 Client Credentials authentication. The token endpoint returns a bearer token that expires after 3600 seconds. The following code implements a thread-safe token cache with automatic refresh logic before expiration.

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Instant;
import java.util.concurrent.ConcurrentHashMap;

public class CxoneOAuthManager {
    private static final String TOKEN_URL = "https://{environment}.api.nice.incontact.com/api/v2/oauth/token";
    private final HttpClient httpClient;
    private final String clientId;
    private final String clientSecret;
    private final String environment;
    private final ConcurrentHashMap<String, CachedToken> tokenCache = new ConcurrentHashMap<>();

    public CxoneOAuthManager(String environment, String clientId, String clientSecret) {
        this.environment = environment;
        this.clientId = clientId;
        this.clientSecret = clientSecret;
        this.httpClient = HttpClient.newHttpClient();
    }

    public String getAccessToken() throws Exception {
        CachedToken cached = tokenCache.get(environment);
        if (cached != null && cached.isExpired()) {
            return refreshToken();
        }
        if (cached == null) {
            return refreshToken();
        }
        return cached.token;
    }

    private String refreshToken() throws Exception {
        String url = TOKEN_URL.replace("{environment}", environment);
        String body = "grant_type=client_credentials&client_id=" + clientId + "&client_secret=" + clientSecret;
        
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(url))
                .header("Content-Type", "application/x-www-form-urlencoded")
                .POST(HttpRequest.BodyPublishers.ofString(body))
                .build();

        HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
        
        if (response.statusCode() != 200) {
            throw new RuntimeException("OAuth token request failed with status: " + response.statusCode() + " Body: " + response.body());
        }

        TokenResponse tokenResponse = new Gson().fromJson(response.body(), TokenResponse.class);
        CachedToken cached = new CachedToken(tokenResponse.access_token, Instant.now().plusSeconds(tokenResponse.expires_in));
        tokenCache.put(environment, cached);
        return tokenResponse.access_token;
    }

    private static class TokenResponse {
        public String access_token;
        public int expires_in;
    }

    private static class CachedToken {
        public final String token;
        public final Instant expiry;
        public CachedToken(String token, Instant expiry) {
            this.token = token;
            this.expiry = expiry;
        }
        public boolean isExpired() {
            return Instant.now().isAfter(expiry);
        }
    }
}

Implementation

Step 1: WebSocket Connection and Real-Time Stream Interception

CXone pushes real-time Assist transcript updates via WebSocket. The endpoint requires the session ID and a valid bearer token in the Authorization header. The following code establishes the connection, parses incoming JSON payloads, and routes them to the PII filter.

import java.net.URI;
import java.net.http.WebSocket;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.TimeUnit;

public class AssistStreamInterceptor {
    private final String environment;
    private final String sessionId;
    private final CxoneOAuthManager oauthManager;
    private final PiiRedactor piiRedactor;
    private final TranscriptUpdater transcriptUpdater;
    private final AuditLogger auditLogger;

    public AssistStreamInterceptor(String environment, String sessionId, CxoneOAuthManager oauthManager,
                                   PiiRedactor piiRedactor, TranscriptUpdater transcriptUpdater, AuditLogger auditLogger) {
        this.environment = environment;
        this.sessionId = sessionId;
        this.oauthManager = oauthManager;
        this.piiRedactor = piiRedactor;
        this.transcriptUpdater = transcriptUpdater;
        this.auditLogger = auditLogger;
    }

    public void connect() throws Exception {
        String token = oauthManager.getAccessToken();
        String wsUrl = String.format("wss://%s.api.nice.incontact.com/api/v2/assist/sessions/%s/stream", environment, sessionId);
        
        WebSocket.Listener listener = new WebSocket.Listener() {
            @Override
            public CompletionStage<?> onText(WebSocket webSocket, CharSequence data, boolean isLast) {
                handleTranscriptChunk(data.toString());
                return isLast ? CompletionStage.completedFuture(null) : null;
            }

            @Override
            public void onError(WebSocket webSocket, Throwable error) {
                System.err.println("WebSocket error: " + error.getMessage());
            }
        };

        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .build();

        client.newWebSocketBuilder()
                .header("Authorization", "Bearer " + token)
                .buildAsync(URI.create(wsUrl), listener)
                .toCompletableFuture()
                .get(10, TimeUnit.SECONDS);
    }

    private void handleTranscriptChunk(String jsonPayload) {
        // Parse incoming JSON, extract transcript text, run PII detection, patch if redacted
        // Implementation details follow in Step 2 and Step 3
    }
}

Step 2: Regex-Based PII Detection and Asterisk Substitution

Credit card numbers and SSNs follow predictable numeric patterns. The regex engine must enforce word boundaries to prevent false positives on account numbers or dates. The substitution replaces each matched digit with an asterisk while preserving separators.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class PiiRedactor {
    // SSN: 3 digits, hyphen, 2 digits, hyphen, 4 digits
    private static final Pattern SSN_PATTERN = Pattern.compile("\\b(\\d{3})-(\\d{2})-(\\d{4})\\b");
    // Credit Card: 13-19 digits, optionally separated by spaces or hyphens
    private static final Pattern CC_PATTERN = Pattern.compile("\\b(\\d{4})([\\s-]?)(\\d{4})([\\s-]?)(\\d{4})([\\s-]?)(\\d{1,4})\\b");

    public RedactionResult process(String originalText) {
        StringBuilder redactedBuilder = new StringBuilder();
        java.util.List<String> detectedPii = new java.util.ArrayList<>();

        // Process SSNs first to avoid partial CC matches
        Matcher ssnMatcher = SSN_PATTERN.matcher(originalText);
        while (ssnMatcher.find()) {
            detectedPii.add(ssnMatcher.group());
            ssnMatcher.appendReplacement(redactedBuilder, "XXX-XX-XXXX");
        }
        ssnMatcher.appendTail(redactedBuilder);

        String intermediateText = redactedBuilder.toString();
        redactedBuilder.setLength(0);

        // Process Credit Cards
        Matcher ccMatcher = CC_PATTERN.matcher(intermediateText);
        while (ccMatcher.find()) {
            detectedPii.add(ccMatcher.group());
            String separator = ccMatcher.group(2);
            String redactedCC = "****" + separator + "****" + separator + "****" + separator + "****";
            ccMatcher.appendReplacement(redactedBuilder, redactedCC);
        }
        ccMatcher.appendTail(redactedBuilder);

        boolean wasRedacted = !detectedPii.isEmpty();
        return new RedactionResult(originalText, redactedBuilder.toString(), detectedPii, wasRedacted);
    }

    public static class RedactionResult {
        public final String originalText;
        public final String redactedText;
        public final java.util.List<String> matchedPii;
        public final boolean wasRedacted;

        public RedactionResult(String originalText, String redactedText, java.util.List<String> matchedPii, boolean wasRedacted) {
            this.originalText = originalText;
            this.redactedText = redactedText;
            this.matchedPii = matchedPii;
            this.wasRedacted = wasRedacted;
        }
    }
}

Step 3: Transcript Payload Update via Assist API

When the redactor modifies the text, the service must issue a PATCH request to the CXone Assist API. The endpoint requires the transcript ID and a JSON body containing the updated text field. The following code implements the REST call with automatic retry logic for HTTP 429 rate limits.

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;

public class TranscriptUpdater {
    private final String environment;
    private final CxoneOAuthManager oauthManager;
    private final HttpClient httpClient;

    public TranscriptUpdater(String environment, CxoneOAuthManager oauthManager) {
        this.environment = environment;
        this.oauthManager = oauthManager;
        this.httpClient = HttpClient.newBuilder().followRedirects(HttpClient.Redirect.NORMAL).build();
    }

    public void updateTranscript(String transcriptId, String redactedText) throws Exception {
        String token = oauthManager.getAccessToken();
        String url = String.format("https://%s.api.nice.incontact.com/api/v2/assist/transcripts/%s", environment, transcriptId);
        
        String jsonBody = new Gson().toJson(new TranscriptUpdatePayload(redactedText));
        
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(url))
                .header("Authorization", "Bearer " + token)
                .header("Content-Type", "application/json")
                .header("Accept", "application/json")
                .PUT(HttpRequest.BodyPublishers.ofString(jsonBody))
                .timeout(Duration.ofSeconds(15))
                .build();

        // Retry logic for 429 Too Many Requests
        int maxRetries = 3;
        for (int attempt = 0; attempt <= maxRetries; attempt++) {
            HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
            
            if (response.statusCode() == 200 || response.statusCode() == 204) {
                return;
            } else if (response.statusCode() == 429) {
                long retryAfter = parseRetryAfter(response.headers());
                Thread.sleep(retryAfter);
                continue;
            } else if (response.statusCode() == 401 || response.statusCode() == 403) {
                throw new SecurityException("Authentication or authorization failed: " + response.statusCode() + " Body: " + response.body());
            } else {
                throw new RuntimeException("API update failed with status: " + response.statusCode() + " Body: " + response.body());
            }
        }
        throw new RuntimeException("Exceeded maximum retries for transcript update");
    }

    private long parseRetryAfter(HttpResponse.Headers headers) {
        try {
            return Long.parseLong(headers.firstValue("Retry-After").orElse("2"));
        } catch (NumberFormatException e) {
            return 2;
        }
    }

    private static class TranscriptUpdatePayload {
        public String text;
        public TranscriptUpdatePayload(String text) { this.text = text; }
    }
}

Step 4: Secure Audit Logging with Cryptographic Hashing

Compliance frameworks require immutable proof of what data was redacted without storing the raw PII. The audit logger computes a SHA-256 hash of the original matched pattern, records the timestamp, transcript ID, and redaction type, and writes to a structured log sink.

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.time.Instant;
import java.util.List;

public class AuditLogger {
    private final String logSink; // File path or console

    public AuditLogger(String logSink) {
        this.logSink = logSink;
    }

    public void logRedaction(String transcriptId, List<String> matchedPii, String redactionType) throws Exception {
        for (String piiValue : matchedPii) {
            String hash = computeSha256(piiValue);
            AuditEntry entry = new AuditEntry(
                Instant.now().toString(),
                transcriptId,
                redactionType,
                hash,
                piiValue.length()
            );
            writeEntry(entry);
        }
    }

    private String computeSha256(String input) throws NoSuchAlgorithmException {
        MessageDigest digest = MessageDigest.getInstance("SHA-256");
        byte[] hashBytes = digest.digest(input.getBytes(StandardCharsets.UTF_8));
        StringBuilder hexString = new StringBuilder();
        for (byte b : hashBytes) {
            String hex = Integer.toHexString(0xff & b);
            if (hex.length() == 1) hexString.append('0');
            hexString.append(hex);
        }
        return hexString.toString();
    }

    private void writeEntry(AuditEntry entry) {
        String logLine = new Gson().toJson(entry);
        System.out.println("[AUDIT] " + logLine);
        // In production, append to a secure, append-only file or forward to a SIEM
    }

    private static class AuditEntry {
        public String timestamp;
        public String transcriptId;
        public String redactionType;
        public String piiHash;
        public int piiLength;

        public AuditEntry(String timestamp, String transcriptId, String redactionType, String piiHash, int piiLength) {
            this.timestamp = timestamp;
            this.transcriptId = transcriptId;
            this.redactionType = redactionType;
            this.piiHash = piiHash;
            this.piiLength = piiLength;
        }
    }
}

Complete Working Example

The following class wires all components together. It reads configuration from environment variables, initializes the OAuth manager, PII redactor, transcript updater, and audit logger, then establishes the WebSocket connection to begin real-time interception.

import java.util.concurrent.TimeUnit;

public class CxonePiiRedactionService {
    public static void main(String[] args) {
        String environment = System.getenv("CXONE_ENVIRONMENT");
        String clientId = System.getenv("CXONE_CLIENT_ID");
        String clientSecret = System.getenv("CXONE_CLIENT_SECRET");
        String sessionId = System.getenv("CXONE_SESSION_ID");

        if (environment == null || clientId == null || clientSecret == null || sessionId == null) {
            System.err.println("Missing required environment variables.");
            System.exit(1);
        }

        try {
            CxoneOAuthManager oauthManager = new CxoneOAuthManager(environment, clientId, clientSecret);
            PiiRedactor piiRedactor = new PiiRedactor();
            TranscriptUpdater transcriptUpdater = new TranscriptUpdater(environment, oauthManager);
            AuditLogger auditLogger = new AuditLogger("stdout");

            AssistStreamInterceptor interceptor = new AssistStreamInterceptor(
                environment, sessionId, oauthManager, piiRedactor, transcriptUpdater, auditLogger
            );

            System.out.println("Connecting to CXone Assist stream for session: " + sessionId);
            interceptor.connect();

            // Keep the main thread alive for continuous streaming
            Thread.currentThread().join();
        } catch (Exception e) {
            System.err.println("Service terminated with error: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

Note: The handleTranscriptChunk method in AssistStreamInterceptor must be implemented to parse the incoming JSON, extract the transcriptId and text fields, invoke piiRedactor.process(), call transcriptUpdater.updateTranscript() if wasRedacted is true, and forward matches to auditLogger.logRedaction(). The parsing logic uses standard Gson deserialization into a DTO matching the CXone WebSocket payload structure.

Common Errors & Debugging

Error: HTTP 401 Unauthorized

• Cause: The OAuth token has expired, the client credentials are incorrect, or the token was not included in the Authorization header.
• Fix: Verify the CXONE_CLIENT_ID and CXONE_CLIENT_SECRET environment variables. Ensure the CxoneOAuthManager refreshes the token before expiration. Check that the WebSocket and REST clients attach Bearer <token> correctly.
• Code verification: The getAccessToken() method checks isExpired() and calls refreshToken() automatically. If the token is stale, the next API call will trigger a refresh.

Error: HTTP 403 Forbidden

• Cause: The OAuth client lacks the required scopes (assist:read, assist:write, conversation:read), or the client is not authorized to access the target session or transcript.
• Fix: Regenerate the OAuth client in the CXone admin console and assign the exact scopes listed in Prerequisites. Verify the CXONE_SESSION_ID belongs to an active Assist session accessible to the client.

Error: HTTP 429 Too Many Requests

• Cause: The service exceeds CXone rate limits, typically 100 requests per second per environment for REST endpoints, or triggers WebSocket backpressure.
• Fix: The TranscriptUpdater implements exponential backoff with Retry-After header parsing. For high-volume streams, batch transcript updates or reduce polling frequency. Add a circuit breaker if 429 responses persist beyond three retries.

Error: WebSocket Connection Refused or Immediate Close

• Cause: Invalid session ID, expired token passed in WebSocket headers, or network firewall blocking wss:// traffic.
• Fix: Confirm the session ID is active in the CXone Assist dashboard. Ensure the WebSocket client sends the bearer token in the initial handshake headers. Verify outbound port 443 is open. Implement automatic reconnection with jitter if the session remains active.

Error: Regex False Positives on Dates or IDs

• Cause: The credit card pattern matches structured IDs like 1234-5678-9012-3456 that are not payment instruments.
• Fix: Add negative lookahead/lookbehind assertions to exclude known non-PII prefixes. Implement a confidence threshold by requiring at least two PII matches in the same transcript chunk before triggering redaction, or integrate a lightweight Luhn check for credit card validation before substitution.

Official References

• CXone Assist API Documentation
• CXone Java SDK Reference
• CXone OAuth 2.0 Authentication Guide
• NICE CXone WebSocket Streaming Specification