Remote work is now standard for most teams. Yet, sharing and collaborating on files still comes with tough choices. You often have to pick between convenience and control, or productivity and privacy. The truth is, you can get both—if you choose the right platform for your security needs.

This review skips the marketing talk and examines four leading options that tackle security in different ways: zero-knowledge encryption, large-scale governance, and secure-by-default features in familiar suites.

Summary — Key takeaways

Match the tool to your threat model: zero‑knowledge for maximum privacy; governance‑heavy platforms for regulated, complex environments.

“Client‑side encryption” means the provider can’t decrypt your content; it can limit some advanced features.

Tresorit and Sync.com lead on end‑to‑end, zero‑knowledge file sharing and are ideal for sensitive data.

Egnyte excels at enterprise‑grade governance, ransomware detection, and compliance workflows.

Google Drive with Client‑side Encryption brings strong security to organizations already standardized on Workspace, including external collaboration support.

How to choose a secure cloud file server

Data sensitivity and threat model

  • Do you need true end‑to‑end encryption (provider can’t decrypt), or is encryption at rest/in transit with strict governance enough?

Compliance requirements

  • Map needs (GDPR, HIPAA, ISO 27001, CMMC/NIST 800‑171, etc.) to vendor controls, certifications, logging, and data residency.

Encryption model and key control

  • Zero‑knowledge/client‑side encryption keeps decryption keys with you.
  • BYOK/KMS or customer‑managed keys can be essential in regulated industries.

Collaboration experience

  • Real‑time co‑editing, external sharing, link controls, watermarking, file requests, and guest access.

Governance and security depth

  • DLP, classification, anomaly/ransomware detection, legal holds, retention, and audit trails.

Ecosystem fit

  • SSO/SCIM, integrations (M365/Google), desktop drive, mobile, APIs, and migration tooling.

Best-in-class picks for 2025

Tresorit — Best for zero‑knowledge collaboration across teams

If your top priority is keeping content unreadable to anyone but the people you authorize—provider included—Tresorit is a strong, polished choice. It uses client‑side, zero‑knowledge encryption across platforms, including web access, so decryption keys and unencrypted files never touch vendor servers Tresorit zero‑knowledge encryption.

What stands out

  • True end‑to‑end encryption by default (zero‑knowledge).
  • Strong external sharing controls with link passwords, watermarking, and revoke.
  • Suitable for regulated industries needing strict confidentiality.

Mind the trade‑offs

  • Some real‑time co‑editing and advanced search/automation features are limited by design in zero‑knowledge models.

Best for: Legal, healthcare, finance, IP‑heavy teams, and any org with a “trust no server” posture.

Sync.com — Best budget-friendly zero‑knowledge for individuals and SMBs

Sync.com delivers end‑to‑end encryption with a clear promise: even the provider can’t see your files. It packages private sharing, branded client portals, and team management into an accessible, affordable bundle—great for small businesses that need serious privacy without enterprise complexity Sync.com overview.

What stands out

  • Zero‑knowledge encryption (“not even we can see them”).
  • Simple, effective sharing and client portals with branding.
  • Competitive pricing, including unlimited storage tiers for teams.

Mind the trade‑offs

  • Fewer enterprise governance automations compared to heavyweight platforms.

Best for: Solo professionals and SMBs that want maximum privacy with minimal admin overhead.

Egnyte — Best for enterprise governance, compliance, and scale

Egnyte approaches security through visibility and control: centralized permissions, sensitive data classification, built‑in ransomware detection, anomaly monitoring, and 50+ out‑of‑the‑box compliance templates. It integrates with M365 and Google Workspace while adding robust governance on top Egnyte enterprise file sharing.

What stands out

  • Unified platform spanning collaboration, threat detection, and compliance.
  • PII/PHI detection, retention/archival, and breach‑notification workflows.
  • Real‑time co‑editing in M365 and Google, secure external collaboration.

Mind the trade‑offs

  • Not end‑to‑end encrypted by default; relies on strong server‑side protections plus governance.

Best for: Mid‑market and enterprise teams balancing collaboration at scale with granular risk and compliance controls.

Google Drive with Client‑side Encryption — Best if you’re standardized on Workspace

Already on Workspace and need stricter controls? Client-side Encryption (CSE) adds an encryption layer that Google servers can’t decrypt, giving you control over keys and access. It’s particularly useful for sensitive or regulated data, with support across Drive, Docs, Sheets, Slides, and external collaboration via visitor sharing. Google Workspace Admin: About CSE, Workspace Updates: External collaboration for CSE files.

What stands out

  • Provider‑blind encryption for high‑sensitivity content within your existing Google ecosystem.
  • External partners can collaborate on CSE files using visitor sharing when configured by admins.
  • Options to use a third‑party or custom key service for key management.

Mind the trade‑offs

  • Some features (e.g., certain smart suggestions, search across encrypted content) can be limited when files are client‑side encrypted.
  • Requires admin setup and key service integration.

Best for: Organizations deeply invested in Google Workspace that need pockets of elevated confidentiality.

Encryption vs. collaboration: finding your balance

Zero‑knowledge/client‑side encryption maximizes privacy; expect constraints on server‑side features like full‑text indexing, certain AI functions, or real‑time co‑authoring.

Governance‑centric platforms optimize productivity and oversight—with powerful DLP, anomaly detection, and compliance—while trusting provider‑side security for decryption.

Many organizations blend approaches: a zero‑knowledge tool for high‑sensitivity work and a governance‑rich platform for day‑to‑day collaboration.

Implementation Tips That Work

Start small. Choose one important team and set a clear goal, like stopping email attachments for client files.

Sort your data. Decide what needs end-to-end encryption and what can be managed centrally.

Get the basics right. Require SSO, MFA, device checks, and least-privilege access.

Control sharing. Use expiring links, passwords, watermarks, and download limits for outside sharing.

Automate protection. Enable DLP, data classification, and threat detection tools where you can.

Train with purpose. Give short, role-specific guides instead of broad security training.

Test your plan. Run practice scenarios like lost laptops, mis-shared folders, or ransomware attacks.

Conclusion

There’s no one “most secure” cloud file server—just the one that best aligns with your risk profile and workstyle. If confidentiality trumps everything, choose a zero‑knowledge platform like Tresorit or Sync.com. If you need cross‑suite co‑editing plus rigorous governance and compliance, Egnyte is a standout. If you live in Google Workspace and need stronger protections where it counts, enable Client‑side Encryption for those workloads.