AvTools Sign & Seal
Electronic signatures built for aviation records
Inspection reports, scrap logs, and quality forms sealed with standards-based digital signatures, independent timestamps, and an append-only audit trail, designed to align with the acceptance criteria in FAA Advisory Circular 120-78B.
Holding an AvTools-sealed document? Enter its certificate ID to verify it, with no account needed.
How every sealed document is protected
Open, verifiable standards, not proprietary claims. Each guarantee below can be independently checked by your inspectors, your customers, or their regulators.
Cryptographic digital signature
Every sealed document carries a PAdES digital signature (the ISO 32000 / ETSI standard used across regulated industries). Open it in any standard PDF reader: Adobe Acrobat validates the seal and flags any modification made after signing.
Independent trusted timestamp
Each seal is countersigned by an RFC 3161 timestamp authority, an independent third party attesting to exactly when the document was sealed. The signing time can't be backdated, even by us.
Certificate ID on every document
Every sealed record is issued a unique certificate ID, printed on the document itself. Anyone holding the document can confirm its authenticity on our public verification page, with no account required.
Tamper evidence by construction
The signature is computed over a SHA-256 digest of the exact file. Change one character, even one pixel, and verification fails. What was signed is what you hold.
Original and sealed copies retained
The as-submitted original and the sealed output are both archived against the record, so the pre-signature source is always available for comparison and audit.
Append-only audit trail
Every signing event, including rejected attempts and verification views, is written to an append-only audit log with the signer, timestamp, and how the signer was authenticated. Log entries are never edited or deleted.
See a sealed certificate
This is a real sealed document, not a mockup: a sample incoming inspection report, built with demonstration data and sealed with a PAdES digital signature by the same pipeline that seals production records.
Download it and open it in Adobe Acrobat: the signature panel shows the seal, the signing certificate, and that the document has not been modified since sealing. The sample is signed with a demonstration certificate; production seals chain to the company signing certificate, carry an RFC 3161 trusted timestamp, and print a certificate ID anyone can verify on this site.
Download the sample PDF
Alignment with FAA AC 120-78B
AC 120-78B describes what makes an electronic signature acceptable for aviation maintenance and inspection records. Here is how Sign & Seal addresses each criterion.
Uniqueness: the signature identifies one specific individual
Each named seal identifies its signer by name, role, and inspector stamp number where assigned. Named signing authority is designated by the customer's admin and defaults to denied. The identity comes from that company's configured source: Microsoft Entra for some companies, and the signer's AvTools account for others.
Significance & intent: signing is a deliberate act
A seal is never applied implicitly. The signer must complete an explicit attestation, affirmatively acknowledging what they are signing and that they are authorized to sign it, at the moment of sealing. The attestation text is stored with the record.
Scope: it is clear what is being attested
The signature is cryptographically bound to the exact document version via its SHA-256 digest, and the record stores the document type and reference. There is no ambiguity about which content the attestation covers.
Signer authentication
Signing runs in an authenticated platform session or through a trusted calling application, and the authentication method and time asserted by that application are recorded. AvTools does not yet perform a fresh, independent Entra OIDC verification when the user clicks sign; that stronger sign-time check is planned, not shipped.
Non-repudiation
The PAdES signature, independent RFC 3161 timestamp, stored attestation, and audit trail preserve the recorded provenance and make later changes detectable. Any third party can confirm the certificate through the public lookup; the authentication method shown on the record states the assurance level used.
Traceability & record integrity
Post-signature modification is detectable in any standard PDF reader. The append-only audit log preserves the full event history of each record, and the original unsealed document is retained alongside the sealed copy.
Retention & retrievability
Sealed records, their originals, attestations, and audit history are retained together and retrievable on demand by certificate ID, supporting the record-retention procedures your certificate or quality system requires.
A note on what “compliance” means here
The FAA does not approve or certify electronic-signature products. AC 120-78B provides acceptance guidance: each certificate holder adopts its own electronic-signature and recordkeeping procedures, typically coordinated with its principal inspector. AvTools Sign & Seal is designed so those procedures can be built on it and satisfy the AC’s criteria. We supply the signature mechanics, the verification chain, and the audit evidence; your quality system supplies the procedure. We’re happy to support that conversation with your PI or auditor. Current seals record the authentication source used, but they do not perform a fresh, independent Entra OIDC check at the signing click. That sign-time verification is planned and is not part of the current product.
Bring verifiable signatures to your quality records
Sign & Seal is part of the AvTools platform for aviation parts companies and repair stations, alongside photo QC, filing, and quoting.