Security at Cerno

Cerno is run by Horsfall Ventures Ltd, a company registered in England and Wales (company number 17311818), trading as “Cerno”. For the third parties that handle your data, see our sub-processor list. For how we use personal data, see our privacy policy.

Staff and advisors in Cerno draft and propose. Anything that would be sent, published or paid for waits for a person to approve it first. Work that asks for approval stops in a waiting state until someone with the right to approve says yes; in a shared office the owner decides who may approve.

AI work costs money, so spending is capped in code, not just shown on a screen. Plan limits and the office’s Energy meter stop work that would go over, and a project’s own pound cap is enforced the same way, with alerts as it fills. Work done by a member of a shared office counts against the owner’s limits, not an unlimited allowance of their own. Requests are also rate limited.

• Row level security. The database itself refuses to hand a signed-in person any row that is not theirs, even if someone talks to the database directly and skips the website. People you invite to a shared office can read only what that office shares with them, and can write nothing directly.
• Server-only tables. Sensitive records, such as invitations, approval requests, the activity trail and live presence, are locked so that no signed-in user, and no one using a public key, can read or write them at all. Only our server can.
• Roles are checked on every request. Owner, member and viewer are read from the database each time. A viewer cannot change anything, spend anything or start any AI work. Removing a member ends their access on their next request.
• Invitations. An invitation link is single use, expires, can be revoked, and only works for the verified email address it was sent to. We store only a one-way hash of it.

In a shared office a person can mark a task private. Other members cannot see it, and neither can the owner: the owner sees a redacted cost line only. The filed result of a private task is kept out of the owner’s file view too. This is enforced in the database as well as in the application.

Be clear about what private means: the text of a private task is still sent to the AI provider that does the work, exactly like any other task. Private controls who in your office can see it, not whether the AI provider processes it. See the sub-processor list.

When you dictate, the short recording is passed to the speech provider to turn it into text and is then dropped. Cerno does not store the audio. When a reply is read aloud, the text is turned into speech and the sound is not kept either.

Files in an office are kept in private storage that belongs to that office. They are served through our server after it checks who you are and what you may see, and one office’s files are not readable from another account. We do not currently scan uploaded files for viruses.

• Features ship behind switches. New or sensitive features, such as the shared office, are off until we turn them on, so they cannot reach anyone by accident.
• Every database change is a written migration, and database rules are reviewed as code.
• Tests run before every release. Type checks, automated tests and a build must pass before code is pushed. That includes tests that fail if an office route is added without a decision about who may use it.

Connections to Cerno and between Cerno and its providers are encrypted in transit (HTTPS). The website is hosted on Vercel and the database, sign-in and file storage are on Supabase. Payments are handled by Stripe. The full list, with what each one sees, is on the sub-processors page.

So that nothing here is overstated, these are things you may expect from a larger supplier that Cerno does not have today:

• No SOC 2 or ISO 27001 report or certification.
• No independent penetration test.
• No single sign-on (SSO) and no enforced two-step sign-in for a company.
• No uptime guarantee or service level agreement (SLA), and no public status page.
• No choice of where your data is stored (no UK-only or EU-only data residency).
• No customer-exportable audit log.

Some of these are planned. We will not describe any of them as available until it is.

If you think you have found a security problem in Cerno, please tell us before telling anyone else. We do not yet have a dedicated, monitored security mailbox, so please use our contact address and put Security in the subject:

hello@cerno.solutions (subject: Security)

Say what you found and how to reproduce it, and please do not access other people’s data or disrupt the service while testing. Our machine-readable contact details are at /.well-known/security.txt.