Tessera Office

Labelled Documents, Edited Where They Live

Name: Tessera Office
Brand: Tessera

An office editor for documents, spreadsheets and presentations that carry a NATO confidentiality label. The marking is always on screen, and every save produces a sealed document. Available for Windows and Linux.

Overview

Tessera Office opens protected documents directly from the Tessera Datalake or from a local folder. The key to a document is released only after the key access service has checked the reader's clearance against the document's label. The document is then opened for editing with no extra step for the user.

The editor works in the Office Open XML formats (.docx, .xlsx, .pptx). Its interface follows the ribbon layout that Microsoft Office users know, so no retraining is needed.

The same application runs on Windows and on Tessera Desktop for Linux. A document written on one platform opens on the other with the same marking and the same protection.

The Tessera Office start page with options to create a blank document, workbook or presentation. — **One editor for three document types.** New documents start unlabelled and receive their marking before they are saved.

Capabilities

Every function that touches the label is part of the editor, not an add-on to it.

Marking always visible

A banner above the ribbon shows the classification and releasability of the open document, with one colour for each level. A document without a label says so in the banner.

Labels from the policy

The classifications and categories on offer are read from the domain's security policy (XMLSPIF). The page marking is written into the document in the form the policy prescribes.

Protected passages

Select a passage and give it its own marking. Readers cleared for the passage see it in place. Other readers open the rest of the document, and the passage stays encrypted.

Sealed on save

Saving binds the label to the content with a digital signature and encrypts the result. A change to the content or to the label after sealing is detected when the document is opened.

No plaintext on the server

Documents travel to and from the datalake in sealed form. Storage nodes never hold a readable copy and never hold the keys.

Windows and Linux

One editor, one document format and one set of markings on both platforms. Users move between a Windows workstation and Tessera Desktop without conversion.

Tessera Office at Work

The screenshots use TESSERA, a fictional demonstration policy, and fictional exercise content. No real classification marking is shown.

Tessera Office on Linux with a document labelled TESSERA CONFIDENTIAL, releasable to ARC and SYL. The banner shows the marking, and the page header carries the same marking. — **Banner and page marking agree.** After a label is applied, the banner shows it and the page header carries the marking that the policy prescribes. The Tessera tab holds the label functions.

The Apply label dialog in Tessera Office with the TESSERA policy, the CONFIDENTIAL classification and releasability to ARC and SYL. — **Apply label.** The policy defines the fields. The marking that results is shown at the top of the dialog before it is applied.

A paragraph in Tessera Office marked SECRET and protected separately from the rest of the document. — **A protected passage.** The paragraph carries its own marking and is encrypted separately when the document is saved.

Tessera Office on Windows showing an operation order. Two paragraphs are readable and a protected passage is shown as a black block. — **A reader who is not cleared for a passage**, on Windows. The rest of the document opens normally, and the passage stays withheld.