# Trusted Signatures

> Seal PDFs with cryptographic trust. Stop invoice fraud. Prove authenticity.

- **Website**: https://trusted-signatures.com
- **Uneed Page**: https://www.uneed.best/tool/trusted-signatures
- **Pricing**: Paid
- **Category**: Business
- **Tags**: E-Commerce, Cryptography, Security
- **Submitted by**: @trusted-signatures
- **Launch Date**: 2025-11-27
- **Social Links**: [LinkedIn](https://www.linkedin.com/company/trusted-signatures)

## About

Most document fraud is simple: someone edits a PDF after it leaves your system. Trusted Signatures prevents that by sealing each file with a cryptographic signature and an optional TSA timestamp. If the file changes—even by one pixel—the seal breaks and verification fails.

How it works

- Your system generates a PDF and sends it to our CLI, API, or Zap. We send a digest (never your PDF) to our server. 

- We sign in hardware (HSM) and return a detached CMS/PKCS#7.

- You attach the seal to the PDF; it verifies in Acrobat and our web validator.

- Recipients can check authenticity without installing anything.

What you can do

- Seal outgoing invoices so AP teams know they’re safe to pay.

- Require sealed bids and verify they weren’t opened or changed.

- Timestamp compliance reports so audit teams see when they were finalized.

- Embed verification in your product to stop “fake PDFs” at the edge.

What it isn’t

- Not a DocuSign competitor. No multi-party signature routing or approvals—just strong sealing and verification.

Key features

- Adobe-trusted seals (AATL/EUTL chain)

- RFC 3161 TSA timestamping (optional)

- API + CLI; accepts SHA-256 digest, returns detached CMS (PKCS#7)

- Policy checks (DocMDP/permissions) and chain-of-custody metadata

- Web validator for recipients; works offline in Adobe Acrobat

- HSM-backed keys (AWS) with per-customer options

- Works with PDF 1.x and 2.0; supports PAdES-style detached signatures

Who it’s for
Accounts Payable, Compliance/Risk, Government procurement, and SaaS teams that need document authenticity without building an e-signature product.

Use cases

- AP invoice sealing and inbound verification

- Sealed bids and tenders (verify open time with timestamps)

- Sealed compliance reports / attestations

- Vendor documents (licenses, certificates, statements of work)