Serious spreadsheets the host can never read.
Prismara Lattice is the spreadsheet app in Prismara Work. It recalculates large workbooks fast, supports modern dynamic-array formulas, and lets your team edit and discuss the same sheet in real time, with every cell encrypted on their own device. Excel and LibreOffice workbooks open and save both ways, formulas included.
What Prismara Lattice does
Fast recalculation
Adding rows to a workbook with 100,000 formulas takes milliseconds, so large models stay responsive.
Dynamic arrays
Formulas spill into neighbouring cells, with #SPILL! errors, A1# spill references and the @ operator, as in current Excel.
Formulas that survive the round trip
Workbooks open and save as .xlsx and .ods with their formulas intact, so Excel and LibreOffice users can keep working with you.
Threaded cell comments
Discuss a cell in a thread. Commenters can add, answer and resolve; authors can edit their own comments.
Real-time co-editing
Several people work in the same sheet at once, merged without the server seeing the data.
Stored with your files
Workbooks live in Geode and Spaces alongside documents and presentations.
How it's secured
Prismara Lattice follows the engineering rules shared across the suite, plus these product-specific measures.
Encrypted on your device
Cell contents are encrypted before they leave your device, so the server stores ciphertext only.
Signed edits
Every author's changes are signed and chained, so altered or withheld edits are detected.
Post-quantum key exchange
Workbook keys are shared with a hybrid X25519 and ML-KEM-768 exchange.
Connects to the rest of the suite
Want SovSec to run it for you?
SovSec provides managed security, SOC and Microsoft 365 services for organisations in the UK and DACH region, and can run Prismara as part of that service.