Evidence, privacy and control, by design.
A signed agreement is only as good as the proof behind it. Qasha keeps that proof complete, keeps it private to the people who need it, and keeps the keys with the people they belong to.
What a sealed copy proves
When the last person signs, Qasha seals the signed copy as the last thing written into it. The seal names the moment it was made and covers every byte of the file, so a change anywhere breaks it. The certificate of completion is a separate file that names the signed copy by its fingerprint.
- SHA-256
- 3f9a 2c1b 7d40 e8c6 … 51ad 9e21
- Timestamp
- 6 Nov 2026 · 10:42:18 UTC, from a trusted authority
- Signers
- Ada Obi, Tunde Bakare · each verified by email code
Signing evidence
Every signature can be checked, by you and by anyone holding the signed copy.
Each signer confirms a one-time code sent to their email. A code lasts ten minutes and allows five attempts, and only five codes can be requested in an hour.
Each completed copy is sealed with an RFC 3161 timestamp from a trusted authority, so any PDF reader shows whether a single byte has changed. Only a fingerprint of the file is sent to the authority.
The document, its version and its attachments are fixed by their fingerprints when sent; if anything no longer matches, signing stops.
Signers receive a certificate of completion. The full audit certificate, with IP addresses and devices, is kept for your team alone.
Access you control
Decide who can see, edit and send each document.
Share with named people or the whole company, with read or edit access, a classification level and an optional password.
Keep a passage private to certain people; anyone else receives a copy with it barred.
Share a document by link when you choose to, see who views it, and stop sharing at any time.
Approval policies make sure the right people approve the exact version before it is sent.
Credentials and AI
Connections stay personal, and automation stays within limits.
A mailbox, model or app connection belongs to the person who authorized it. Credentials are encrypted with AES-GCM, and changing them requires checking them again.
Each request keeps to the model connection it started with; one person’s requests never borrow another’s model, key or context.
Follow-ups check the inbox before they go, uncertain payment outcomes are held for review, and pricing commitments stay with your people.
Qasha shows what evidence is missing; approving a customer stays with your reviewer.
Reporting a security issue
If you believe you have found a security issue in Qasha, please tell us through our contact page before sharing it elsewhere, and give us a chance to fix it.
Bring the whole deal into one place.
We’ll walk through your process, from first email to recurring invoice, and show you where Qasha fits.