In sectors like healthcare, finance, legal services, and government, organizations increasingly turn to S/MIME (Secure/Multipurpose Internet Mail Extensions) to meet security and compliance requirements. But while S/MIME offers strong authentication and encryption, it also introduces operational complexity, particularly around certificate lifecycle management.
Issuing, renewing, and revoking certificates for hundreds or thousands of users is unsustainable without automation. That’s why today’s best encryption tools are judged on cryptographic strength and how well they integrate, scale, and automate certificate workflows.
This article identifies five leading encryption platforms built to streamline S/MIME deployment, reduce IT overhead, and ensure messages stay secure throughout the certificate lifecycle. Rather than rank them generically, we group them by use-case strength, highlighting how each provider fits into real-world certificate automation strategies.
Why S/MIME Automation Matters
S/MIME is widely regarded as a gold standard for email encryption and digital signing, especially in industries where authenticity, confidentiality, and integrity of messages are paramount. However, despite its strong cryptographic foundation, S/MIME’s operational complexity often becomes a barrier to adoption—particularly in large or fast-growing organizations.
In its manual form, S/MIME involves several time-consuming and error-prone tasks:
- Issuing a certificate per user, often through a public or private certificate authority (CA), and then provisioning that certificate to local mail clients or mobile devices
- Manually renewing certificates on an annual or semi-annual basis, depending on policy and vendor expiration timelines
- Revoking and reissuing certificates promptly in the event of role changes, device loss, employee departures, or compromise
- Validating trust chains and digital signatures on the recipient side to confirm the origin and integrity of messages
For teams managing hundreds or thousands of mailboxes, this process can quickly become unmanageable. Without automation, IT teams face onboarding delays, compliance gaps, and inconsistent user experiences—especially when managing remote users or federated environments across Microsoft 365, Google Workspace, and mobile platforms.
That’s where automation becomes critical. Modern email encryption platforms increasingly integrate directly with trusted certificate authorities like DigiCert, GlobalSign, and Sectigo, enabling:
- Policy-based certificate issuance during user onboarding
- Automated renewal and expiration alerts to maintain continuity
- Immediate revocation workflows tied to identity management systems (e.g., Azure AD, Okta)
- Real-time reporting and audit trails for regulatory compliance
When implemented correctly, S/MIME automation ensures that email security is applied uniformly, even as users change roles, switch devices, or operate across different geographies. More importantly, it reduces the burden on IT teams, speeds up user provisioning, and provides the level of traceability required by laws like HIPAA, GDPR, and SOX.
In short, without automation, S/MIME is secure but brittle. With it, it becomes a sustainable pillar of modern enterprise communication.
How the Top 5 Providers Compare
| Provider | S/MIME Automation | Certificate Authority Integration | MYOK/BYOK Support | Platform Integration | Best Fit For |
| Echoworx | Full automation (issue/renew/revoke) | DigiCert, SwissSign | MYOK (AWS) | Microsoft 365, Gmail | Complex, large-scale deployments |
| Microsoft Purview | Manual setup, no automation | Microsoft CA (limited APIs) | BYOK (Azure) | Microsoft 365 | Internal compliance teams |
| Zix (OpenText) | Basic renewal support | Built-in CA | No | Outlook, Exchange | Legacy Outlook shops |
| Entrust | Automated issuance and lifecycle APIs | Native CA (Entrust) | BYOK support | Microsoft 365, custom apps | Enterprises requiring in-house PKI |
| Virtru | No S/MIME support | N/A | BYOK (Google) | Gmail, Google Workspace | Teams not using S/MIME |
1. Echoworx – Best for Scalable, Policy-Based Certificate Automation
Echoworx stands out for its full automation of the S/MIME lifecycle, including certificate issuance, renewal, and revocation. It integrates directly with certificate authorities like DigiCert and Entrust, enabling policy-based controls that reduce manual oversight. Echoworx supports MYOK via AWS KMS, allowing enterprises to retain key sovereignty and meet data residency requirements across jurisdictions.
Beyond S/MIME, Echoworx offers multiple encryption methods (PGP, TLS, portal), full branding control, and seamless integration with both Microsoft 365 and Google Workspace. For large, multinational organizations, this flexibility makes it easy to enforce encryption standards across varied environments and recipient types.
Ideal For: Financial institutions, global enterprises, and regulated industries managing encryption at scale.
Ideal For: Microsoft-focused enterprises with internal compliance mandates and a limited S/MIME footprint.
2. Zix (OpenText) – Best for Legacy Microsoft Environments
Zix’s S/MIME support is solid but dated. It allows organizations to assign certificates to users via ZixGateway, applying encryption automatically based on message content or user policy. While it doesn’t offer certificate automation per se, it simplifies secure delivery for Outlook and Exchange users without requiring client-side intervention.
For firms using older infrastructure or maintaining hybrid on-prem email systems, Zix can serve as a dependable intermediary, especially when combined with its branded portal and message tracking capabilities.
Ideal For: U.S.-based institutions still anchored to legacy Outlook/Exchange deployments.
3. Microsoft Purview – Best for Microsoft-Centric Workflows
Microsoft Purview provides native S/MIME capabilities within Microsoft 365 but lacks automation tools for certificate lifecycle management. Admins can deploy certificates manually via Group Policy, PowerShell, or Microsoft Endpoint Manager, but this approach doesn’t scale well without custom scripting or external tooling.
On the compliance side, Purview integrates tightly with Azure Information Protection and supports BYOK via Azure Key Vault, making it useful for internal messaging security where certificate volume is relatively low or managed centrally.
4. Entrust – Best for In-House PKI and Native Certificate Control
Entrust is both a certificate authority and a platform provider. It supports automated certificate lifecycle management with rich policy configuration, API access, and strong integration with enterprise IT environments. Organizations can issue S/MIME certificates from Entrust’s cloud or on-prem certificate authority, allowing greater flexibility in building custom PKI frameworks.
Entrust offers tools for internal provisioning, policy enforcement, and revocation tracking. While it lacks some of the user experience features seen in broader encryption platforms, its strength lies in granular certificate orchestration for security teams with dedicated resources.
Ideal For: Enterprises running private PKI infrastructure or requiring custom certificate automation policies.
5. Virtru – Best for Teams Avoiding S/MIME Altogether
While not a solution for S/MIME automation, Virtru is included here to represent a growing class of providers offering non-certificate-based encryption models. Built for Gmail, Virtru uses client-side, zero-trust encryption and integrates with Google’s External Key Manager for BYOK support. Its model avoids certificates entirely, instead focusing on user-friendly access control and audit features.
This is an attractive alternative for teams that find S/MIME too complex or burdensome to deploy, but still require compliance with HIPAA, CCPA, or GDPR.
Ideal For: Google Workspace-based teams prioritizing simplicity and user experience over formal certificate frameworks.
Automation is the New Baseline
S/MIME remains essential for organizations that require email authenticity and strong encryption, but managing it manually is no longer sustainable. Whether your team is scaling a global deployment or managing certificates for a few high-risk departments, automation tools are now a must-have, not a luxury.
- Use Echoworx for full automation and cross-cloud policy enforcement
- Use Entrust for in-house PKI and custom lifecycle management
- Use Microsoft Purview for internal messaging and Azure-native compliance
- Use Zix for basic encryption in legacy Microsoft environments
- Use Virtru if you’re moving away from certificate dependency altogether
Before committing, assess your certificate volume, user onboarding frequency, and regulatory scene, then align with a vendor that makes automation not just possible, but painless.