Client confidentiality in the digital age: the tools lawyers actually need.

This article covers the specific tools. For the threat model behind these decisions, why law firms are targeted, what attackers are after, and how to assess your own exposure, see: Digital security for lawyers, understanding the threat.

Encrypted email

Proton Mail provides end-to-end encryption by default between Proton accounts. For external recipients, clients, opposing counsel, courts, it supports PGP encryption and a password-protected secure message option that does not require the recipient to have a Proton account. The servers operate under Swiss jurisdiction. For a lawyer communicating sensitive client information by email, the switch from a standard account eliminates the most common interception vector at the transport layer.

What Proton Mail does not cover: metadata. The fact that you communicated with a specific person at a specific time is visible at the network level regardless of encryption. For matters where even the existence of communication is sensitive, use a different channel entirely.

The compliance-side framing of the same choice, including which legal basis applies and what regulators expect to see in an audit, is in our GDPR compliance guide for solo lawyers and small firms.

Password management

1Password generates unique strong credentials for every system and stores them encrypted locally and in the cloud. For a law firm, the shared vault feature allows credential sharing between staff without exposing the underlying passwords, a staff member can use a credential without ever seeing it. Emergency access provisions allow continuity if a key staff member is unavailable. Travel Mode hides designated vaults at border crossings, making them invisible to device inspection.

The full operational picture of the tool, with the trade-offs we tested under field conditions, sits in our 1Password review for journalists. The same logic applies to a legal practice: the question is not whether the vendor is credible, but whether your team uses it consistently.

The critical operational point: a password manager only eliminates credential reuse risk if every account that touches client data is in it. A single staff member managing a client portal with a personal password outside the system is a gap.

Secure file sharing

Tresorit provides end-to-end encrypted file storage and sharing. Unlike Dropbox or Google Drive, the encryption keys are held by the user, not the platform. A legal hold, a government request, or a platform breach cannot expose files that Tresorit itself cannot decrypt. For client documents, due diligence packages, and privileged communications stored outside email, this matters.

ProtonDrive is an alternative in the same category, with the advantage of integration with a Proton Mail account. For practices already using Proton Mail, a single provider reduces the number of systems to manage and audit.

Device encryption and access control

FileVault on macOS and BitLocker on Windows encrypt the full disk. A seized or stolen device with full-disk encryption and a strong passphrase is inaccessible without the key. This is not a substitute for not carrying sensitive data on travel devices, it is the minimum baseline for any device that ever touches client files.

Access control means: unique credentials for every staff member on every system, multi-factor authentication on every client-facing portal, and a documented offboarding process that revokes access immediately when a staff member leaves. Most firm breaches involving former staff could have been prevented by the last point alone.

Frequently asked questions

Do clients need to use the same tools?

For encrypted email to work end-to-end, both parties need a compatible system. Proton Mail’s password-protected secure message option bypasses this for external recipients who cannot or will not switch platforms. For file sharing, Tresorit and ProtonDrive allow sharing with external recipients via secure links without requiring an account.

What about client portals built into case management software?

Most case management portals provide transport encryption (HTTPS) but not end-to-end encryption. The platform can access the content. Evaluate whether the sensitivity of the matter warrants a separate encrypted channel for the most sensitive communications, regardless of what the portal provides.

The adjacent risk of AI-tool use in client work, where the privilege itself can break, is documented in how attorney-client privilege breaks when a law firm uses ChatGPT. The choice of channel is one decision. The choice of which tools touch the matter at all is the other.

Is this only relevant for criminal defence or high-profile matters?

No. Corporate transactions, family law, employment disputes, and regulatory matters all involve communications that would be valuable to an adversary. The sensitivity of the matter determines the threat, not the practice area.

Should small firms hire an MSP or build this stack themselves?

The four tools above can be deployed by a single non-technical staff member in an afternoon. The harder problem is the discipline of using them consistently across the practice, including with external counsel and clients who are not on the same systems. An MSP does not solve the discipline problem. They solve the deployment and patching problem, which is real but smaller. Most solo and small firms benefit more from documenting their own process and reviewing it quarterly than from outsourcing the question.

Proton Unlimited is the tool we recommend for encrypted email, VPN and secure storage. It’s what we’d use ourselves.

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There’s no perfect setup. Anyone selling you perfect is selling fear. The goal is simple: make yourself a harder target than the person next to you.