Recipients you send to do not need an account — they sign with an emailed link + passcode.
Upload any signed PDF — produced by this app, DocuSign, Adobe Acrobat, HelloSign, foxit, or any tool that follows the PDF signature standard — and we'll show you every signature the file carries, who signed it, when, with what certificate, and whether the document has been altered since signing.
Scan this QR code with your phone's authenticator app (Microsoft Authenticator, Google Authenticator, Authy…):
Or add it manually with this key:
Every signature you apply uses your own X.509 certificate so the signed PDF carries your cryptographic identity (not the app's shared key). Download the public certificate to share with anyone who needs to verify a signature you made.
Installing your cert into your local certificate store lets PDF tools (Acrobat, Foxit, Preview) recognize you as a known signer when reviewing your own signed documents — no more "signer identity unknown" yellow banners. No admin / sudo required for the default user-scoped install.
Windows — easiest path:
Windows — scripted (one-click, no wizard):
.\shepherdsign-install-my-cert.ps1
macOS & Linux:
bash shepherdsign-install-my-cert.sh
Heads up: these installers place the cert in your own personal store — they identify you as a signer. If you instead need to trust someone else's ShepherdSign signature in Acrobat, use the cert-trust installer on the Verify Signature page.
Add and verify a mobile phone number to enable the "Text me a code" option on the sign-in page. Required only if you want SMS as a second factor — Authenticator app and Email codes work without it.
We texted a code to your phone.
✓ Verified — . SMS sign-in is enabled.
SMS delivery isn't configured on this server yet. Authenticator app and Email codes are still available.
Submit a photo of a government-issued ID (driver's license, passport, or national ID card) plus an optional selfie. Required only for High Assurance (ID-verified) documents; not needed for standard contracts that meet the Advanced Electronic Signature (AES) bar. Photos are stored encrypted in private storage and never appear in any signed document.
We only accept JPEG, PNG, HEIC, WEBP, or PDF, up to 10 MB per image. Submitted documents move to "Submitted — pending review" and a human reviewer is alerted; you can resubmit at any time. The document number is masked everywhere in the app (last 4 only).
How ShepherdSign protects each signed PDF with a per-signer X.509 certificate, what those certificates are for, how to download them, and how anyone receiving a signed document can verify that you (or your recipient) actually signed it.
A signing certificate is a small file that proves a particular person's cryptographic identity. It contains a public key (safe to share), the person's name and email, and a digital signature from whoever issued the certificate. Every time you sign a document in ShepherdSign, the app uses the private key paired with that certificate to create a cryptographic seal on the PDF. The public certificate is then embedded inside the signed PDF so that anyone who opens it can verify the seal.
Every signer (you when you send a document, and each recipient who signs one) now gets their own RSA-2048 certificate. The certificate is generated automatically the first time you sign, and it's reused on every document you sign after that. This means each signed PDF carries the distinct cryptographic identity of each person who signed it, rather than a single shared key. The technical name for this kind of signature is PAdES (PDF Advanced Electronic Signature, ETSI EN 319 142).
your.email_at_company.com-signing-cert.pem will be saved to your Downloads folder.The downloaded file is your public certificate only — it cannot be used to sign documents on your behalf, so it's safe to share with anyone who wants to verify a signature you applied.
.pem file is theirs to keep — proof of the identity they used to sign your document.The most common uses:
.pem file as a trusted identity. Acrobat will then show a green checkmark on signatures applied with your certificate.Pick your operating system. Each option installs the certificate into the right system trust store so PDF readers, browsers, and command-line tools recognise signatures from this signer as trusted — no further manual steps.
Today's certificates are self-signed by the ShepherdSign service, so they're not in Adobe's pre-installed Approved Trust List. The "Add to Trusted Certificates" step above is only needed once per signer — after that, every future document signed by that person shows green automatically. See section 8 for what production-grade trust looks like.
If you'd rather verify without Acrobat, OpenSSL can inspect both the certificate and the PDF's signature container:
openssl x509 -in your-signing-cert.pem -text -noout # Look at: Subject, Issuer, Validity, Public-Key, Signature Algorithm. pdfsig signed-document.pdf # pdfsig (from poppler-utils) reports each signature, who signed, and validity.
The certificates issued today are self-signed. That's the correct posture for almost every commercial contract — NDAs, engagement letters, statements of work, sales agreements, offer letters, vendor agreements — and meets the requirements of the U.S. ESIGN Act, UETA, the eIDAS Regulation (Advanced Electronic Signature), UNCITRAL, and most Asia-Pacific regimes.
A small set of high-value or regulated transactions (notarial deeds, certain real-estate
transfers, court filings in some jurisdictions, regulated financial instruments) require a
Qualified Electronic Signature (QES). For those, the certificate must be
issued by a Qualified Trust Service Provider (QTSP) on the EU Trusted List,
with the signer's identity verified against a government-issued ID at issuance time.
ShepherdSign is designed to support this as an add-on; the integration plan
is described in the project's docs/tsp-integration-plan.md.
Q. Do I need to do anything before sending my first document?
No. The certificate is created automatically on first use. You can download a copy any time from the Security tab.
Q. What if my email changes?
A new certificate is issued the first time you sign with your new email. The old certificate stays valid for documents you signed before the change.
Q. Can a recipient sign without an account?
Yes. They get a certificate the first time they sign one of your documents. They can download it from the "Signed ✓" page.
Q. Can the same person have two certificates?
Each email address gets one. If two people share an email address (unusual), they share a certificate — which is why production QES requires real identity verification.
Q. Where is my private key?
In the ShepherdSign service's private Azure Blob Storage. It is only accessed by the service when you sign a document. It is never downloaded to your computer, never emailed, and never exposed via any API.
Q. Is the signed PDF tamper-evident?
Yes. Any byte change to the document after signing invalidates the cryptographic seal. Adobe Acrobat (or any PAdES-aware verifier) will show the signature as invalid if the file has been altered.
Q. What other protections are in place?
Each signature is paired with an RFC 3161 trusted timestamp (so the time of signing is independently provable), the recipient identifies themselves with a one-time passcode sent to their email, and every step is recorded in a tamper-evident hash-chained audit trail. The full legal & regulatory compliance summary is shown to every recipient at the bottom of their signing page.
The short answer is: almost any business or personal contract — NDAs, MSAs, SOWs, sales contracts, engagement letters, employment offers, vendor agreements, leases, financial-services applications, healthcare administrative forms, IP assignments, consumer subscriptions and waivers, and the long tail of routine documents in between. All of these are legally enforceable under U.S. ESIGN/UETA, EU eIDAS AES, UK ECA, UNCITRAL, and the major Asia-Pacific regimes at the posture this app provides today.
The narrow set that cannot be signed at today's posture — primarily notarial
deeds, last wills, certain real-estate transfers in EU civil-law jurisdictions, and a
handful of court filings — is documented in the project's
docs/supported-document-types.md reference, along with the legal regime that
applies to each category. Customers and counsel should refer to that document when in
doubt about a specific transaction type.
If a recipient struggles with verification, or you need an additional copy of a signature for legal or compliance purposes, contact your administrator — they can re-issue the affidavit of execution and confirm the cryptographic chain on your behalf.
| Subject | Type | Status | Signers | |
|---|---|---|---|---|
| Nothing sent yet. | ||||