Original bytes
Private photos and documents are identified by hashes of the exact uploaded bytes and remain tenant-scoped.
Security
Proof is a process, not a badge
SignThatUp earns trust by showing the exact evidence fact behind each status and by naming the assurance that is not present.
One frozen version
Both people sign the same canonical content. A later change becomes another version instead of changing history.
Private evidence, minimal public facts
Private bundles require private access. Public verification avoids names, contact details, photos, and workspace data.
Exactly-once records
Concurrent or repeated completion attempts resolve to one committed record, one usage fact, and one chain entry.