Solo2 Pro for law firms
Defensible professional secrecy (art. 542 LOPJ). Communication with clients that withstands scrutiny in a proceeding.
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The professional use of generic messaging poses problems that a lawyer knows well:
Procedural strategy through an unprotected channel
Case notes, evidence, lines of defense, opposing party assessments — they cross servers in jurisdictions that apply different rules to Spanish professional secrecy. The dogmatic protection of art. 542 LOPJ clashes with the technical reality of the channel.
Evidence in challengeable format
A WhatsApp screenshot is easily manipulated. Without a verifiable timestamp or chain of custody, defending the integrity of content against a procedural challenge is difficult — even when the content is genuine.
Third-party access to history
A firm sharing a device, an unexpected leave of a lawyer, a lost device: the full history of client conversations is accessible to whoever has physical access to the phone. There is no granular control or separation between personal and professional matrix.
What the law says
The lawyer's professional secrecy is regulated in art. 542 of the Organic Law of the Judiciary: the lawyer must keep secret all facts or news they become aware of by reason of any of the modalities of their professional activity, without being forced to testify about them. The Deontological Code of the Spanish Legal Profession (arts. 5 and 21) reinforces it.
This obligation does not allow the lawyer to discharge it by technically delegating the conversation to a third party (the messaging provider) who could — technically or by request of a foreign jurisdiction — access metadata or, in some cases, content.
GDPR overlaps: client data passing through the conversation are personal data, in some cases related to criminal or administrative proceedings. The lawyer is the data controller. The choice of channel is part of the technical and organizational measures required by Art. 32 GDPR.
How Solo2 Pro solves it
Technical confidentiality, not just declared
The content of the conversation with your client does not cross our servers. Point-to-point, end-to-end encryption with X3DH and Double Ratchet. If an international request asks the provider for communication content, there is no content to deliver — because we technically do not possess it.
Technical chain of custody in export
When you need to provide a conversation to a proceeding, you export the relevant time range with a specific client. The generated file includes chained hashes, verifiable local timestamp, and integrity metadata. More robust than a screenshot. Final assessment belongs to the judge, but the document withstands technical scrutiny.
Labels by type of matter
Criminal in red, civil in blue, commercial in green, closed matters in gray. Instant filters by label. Labels are yours only, never synced to the client. Local vault encrypted with the lawyer's 24 words.
Professional identity with firm banner
The client sees the firm's logo at the top of the chat. Editable message: number of solicitors, procedural reminders, duty data. Reduces confusion and reinforces the channel's professional identity.
Defense against a challenge
The technical argument is defensible and reproducible. If the opposing party challenges a message provided by your firm, you can prove:
- •That the communication channel with the client uses publicly verifiable cryptographic primitives (X3DH and Double Ratchet, the same as Signal and validated by the academic community).
- •That the content did not pass through intermediate servers — transfer is direct between devices.
- •That the export file contains a technical chain of custody (sequential hashes, device timestamp).
- •That the integrity of the file is verifiable by an expert designated in the proceeding.
- •That no party other than the lawyer and the client has had technical access to the content at any time.
Frequently asked questions
Would Solo2 cooperate with an authority if requested for communication content?
We couldn't: we don't have the content. What we can technically deliver (existence of the session, connection date, pseudonymized cryptographic identifiers) is listed in our transparency policy. It is not content, it is not real-time location, it is not messages.
Is it useful for communication with clients in criminal proceedings — and therefore with alleged reserved character?
Yes, it is one of the natural use cases. The architecture is the same regardless of the type of proceeding. The conversation between lawyer and client in a private setting is protected by the same technical guarantee as any other. Subsequent legal assessment is the responsibility of the investigating judge, but the material provided in Solo2 format is traceable and verifiable.
What about the rest of the internal communication of the firm (between partners, with solicitors, with experts)?
The firm plan (49 €/month for up to 10 users) covers both client communication and communication between firm members. Each lawyer with their own encrypted identity. Experts can connect as external users or, if you work with them regularly, be added to the plan.
Talk to us
An email to pro@solo2.net telling us the size of the firm, main practice areas, and the specific case you're trying to resolve. A team member will always reply to you within one or two business days. If justified, we organize a call to see it in detail.
pro@solo2.net