Knowledge hub
Learn about document sealing
Practical guides on sealing documents, verifying integrity, and sharing tamper-evident links — written for the way Opcilo actually works. Browse by Understand, Protect, Use, or Compare — or open the glossary.
Use
Business Inbox: receive sealed documents in your workspace
How Opcilo Business Inbox collects sealed shares for your organization — search, status, archive — and how it differs from the Recipient Wallet.
Published Oct 10, 2026 · 7 min
Understand
What Opcilo proves on the verification card
Plain-English guide to Document integrity, Issuer Verified after business verification, Identity Not checked, Signature Not checked, and Trust Badge limits on Opcilo verify.
Published Oct 10, 2026 · 6 min
Protect
Offer letters: how a candidate checks the sealed file
Letterhead and a PDF name are easy to copy. A seal lets a candidate check Document integrity and issuer cues — not that the job is real.
Published Oct 2, 2026 · 5 min
Protect
After signing in DocuSign: proving the signed PDF was not altered
DocuSign records agreement and an audit trail. Opcilo lets anyone check the signed PDF in their hands is still the sealed file — no login.
Published Oct 2, 2026 · 5 min
Compare
These tools answer different questions: Adobe, Dropbox, DocuSign, and Opcilo
Adobe, Dropbox, and DocuSign can produce tamper-evident or audit-trail output. Opcilo adds a no-login check of any sealed file.
Published Oct 2, 2026 · 6 min
Understand
When the version in your hands matters
Submittals, permits, and proposals go wrong when a new file keeps an old name. One seal shows whether the copy you hold is the issued version.
Published Oct 2, 2026 · 6 min
Understand
Why we say tamper-evident
Tamper-proof would claim a file cannot be changed. Tamper-evident is accurate: a change shows up when the recipient checks the seal.
Published Oct 2, 2026 · 3 min
Use
Hierarchical invoices and client confirm: structure, share, then seal
End invoice spam and attachment swaps: hierarchical Pro invoices, share-for-review, client feedback loop, confirm vs issue, seal and Pay Now on one verify link.
Published Sep 26, 2026 · 11 min
Use
Recipient wallet: keep verified documents on this device
How Opcilo Wallet saves documents you receive after verification — local on this device, with optional free-account sync across devices.
Published Sep 17, 2026 · 6 min
Use
Document requests: collect, review, resubmit, and confirm
Create a checklist, share a secure link, review uploads, resubmit rejected items, and confirm — without recipient accounts.
Published Sep 16, 2026 · 10 min
Protect
How Opcilo protects documents: integrity, encryption, and honest limits
Learn how Opcilo uses SHA-256 seals and AES-256 storage on Azure, what end-to-end encryption would mean (and why we don’t claim it), and where to read the full Security page.
Published Sep 16, 2026 · 6 min
Protect
Same filename, real-looking code — why the email attachment still isn’t the seal
A familiar PDF name plus an Opcilo-looking code can still be a trap. See two real attack cases, where risk happens, and how verify + check-my-copy resolve them.
Published Sep 16, 2026 · 6 min
Use
Sealed invoices and Pay Now: get paid on the verified version
Seal an invoice so clients see integrity status and amount due, then pay with Pay Now — reducing disputes over which PDF was final.
Published Sep 16, 2026 · 8 min
Understand
Why document fraud is a bigger problem than most businesses realize — and how sealing helps
Fake invoices and swapped PDFs exploit everyday email trust. Learn how document sealing with SHA-256 proof helps — and what Opcilo does not overclaim.
Published Sep 16, 2026 · 7 min
Use
Bulk Seal: seal many documents without losing per-file proof
Use Bulk Seal on Team to seal a batch of files in one workflow — each document keeps its own seal and verification code, unlike Seal Bundles.
Published Sep 16, 2026 · 8 min
Use
Multi-channel notifications: Email, SMS, and WhatsApp
Learn how Opcilo notifies recipients by Email, SMS, and WhatsApp — and how that differs from pasting a verification link yourself.
Published Sep 16, 2026 · 8 min
Use
Opcilo ID: scan a handle to add a recipient fast
Share an Opcilo ID QR or handle so someone can add you as a document recipient quickly — without typing contact details first.
Published Sep 16, 2026 · 8 min
Use
Recipient groups: reuse named lists for seals and requests
Organize your address book into named recipient groups on Team — reuse partners, AP contacts, and stakeholders on every share and request.
Published Sep 16, 2026 · 8 min
Understand
What is document sealing? How to prove a file hasn't been changed
Learn what document sealing is, how Opcilo creates a tamper-evident verification link, and how recipients prove a file hasn't been altered — without signing in.
Published Sep 15, 2026 · 9 min