Ostensor Bare

The Ostensor board, unpotted.

The same board as Ostensor Potted, sold bare for people who want to inspect it, mount it in their own enclosure, or put it on a bench. Latin, one who shows: a secure domain owns both the display and the key, so a compromised application can’t show you one thing and sign another. One physical press permits at most one signature.

Specifications

• STM32U585 + Infineon OPTIGA Trust M secure element
• Display and key share one secure domain — show-then-confirm signing
• One press, at most one signature
• Bare board — no potting, no enclosure. Handle as you would any exposed electronics.

Read before buying

Show-then-confirm is proven on the bench. On shipping units the security hardening that would make it enforceable against a compromised application is not yet switched on — the mechanism is present, the lock is not. We say which when it changes. A bare board also carries none of the tamper-evidence that the resin pour provides.

Availability

Shipping now, in small runs.

Try one before you buy one

Every attestation device signs a challenge and the record is checked in your browser at verifyknot.io/start — no account, no login. The verdict is computed from the record itself, not handed down by our server.

What it does not do

A signature proves that a specific key signed specific bytes. On its own it does not prove who held the key, that a person was present, or that the contents are true. Each rung of the line adds one of those, and we say which. The timestamp on a record is ours, not an outside authority’s.

Hand-built in small runs in Utah · veteran-owned (SDVOSB) · US shipping with tracking · returns