Mailock for Microsoft 365 is a secure email solution that integrates with Microsoft 365 to provide end-to-end encryption, recipient identity verification, and compliance controls for email communications. It is available as an Outlook add-in for desktop users and as a secure email gateway for high-volume automated delivery via Exchange Online. Encryption is applied using AES-256, securing message content throughout delivery and reply. Recipient authentication is enforced before access is granted, using challenge methods such as SMS, Q&A, or Unipass ID. CRM integration can be used to apply customer-specific authentication checks to reduce the risk of misdelivery. Key compliance capabilities include full message revocation — allowing senders to withdraw access to a sent message at any time, even after it has been opened. This goes beyond Microsoft's native email recall functionality. Message tracking features provide timestamped audit trails covering opens, replies, and downloads, along with read notifications and engagement analytics. Recipients can respond securely via browser or the Outlook add-in without needing to create an account. Encryption can be initiated manually via the Outlook add-in, or applied automatically through policy-based rules or keyword triggers. A separate Automated tier supports large-scale secure communications delivery.