Beyond Encryption Mailock for M365 vs StealthMail: Side-by-Side Comparison (2026)

Beyond Encryption Mailock for M365

SMB and mid-market teams standardized on Microsoft 365 should pick Beyond Encryption Mailock for M365 if message revocation is non-negotiable; the ability to recall emails even after a recipient opens them covers the mistake you'll inevitably make sending sensitive data to the wrong person. AES-256 encryption with SMS and Q&A recipient verification handles NIST PR.AA without requiring users to manage separate identity infrastructure. Skip this if your organization needs DLP that catches data before it leaves the network or if you're already enforcing encryption at the gateway level; Mailock layers on top of M365 rather than replacing email security controls.

StealthMail

Mid-market and enterprise teams handling sensitive email workflows,healthcare, finance, legal,should evaluate StealthMail primarily for its recall and access control capabilities; most competitors encrypt content but can't revoke it post-delivery or prevent forwarding, and StealthMail does both. The hybrid deployment model and user-owned key management (ECC 512+) mean you're not trusting the vendor with your encryption material, which covers the PR.AA and PR.DS functions that matter most for regulated industries. Skip this if your threat model centers on detecting account compromise rather than preventing lateral movement of sensitive emails; StealthMail is a content-control tool, not a mailbox forensics platform.