Mailock Enterprise is a secure email gateway designed for high-volume, enterprise-scale encrypted communications. It enables organisations to send and receive encrypted emails and attachments while optionally applying recipient identity authentication challenges before message access is granted. **Encryption:** Emails and attachments are encrypted using AES-256 encryption. End-to-end encryption is applied to prevent interception during transit. **Recipient Authentication:** Senders can configure authentication challenges that recipients must pass before accessing a message. Supported challenge types include question-and-answer, SMS verification, email verification, and third-party identity solutions such as Unipass ID. API/webhook integration allows challenges to be set dynamically based on CRM data. **Compose & Trigger Controls:** Encryption can be initiated via an Outlook add-in, keyword/trigger-word detection, rule-based configuration, or fully automated workflows. **Message Tracking:** A message tracker provides timestamped records of when secure emails are sent and when secured content is opened, supporting proof-of-delivery requirements. **Compliance:** The product is positioned to support GDPR, FCA, MiFID II, and Consumer Duty obligations. It uses AES-256 encryption aligned with ICO guidance and supports durable-medium delivery requirements. **Integration:** Compatible with Microsoft 365 (including Outlook), Google Workspace, and CRM platforms via API/webhooks, without disrupting existing mail flow tools such as antivirus or server-side signatures.