Use Case

Contract Signing & Attestation

Execute NDAs, vendor agreements, and founder contracts inside the same encrypted vault. Get tamper-evident proof anchored to Bitcoin. The proof does not depend on trusting 1Bridge.

How It Works

From Request to Attested Contract

Signing runs on the same confidentiality model as document sharing.

Create Signing Request

Upload a PDF contract, place signature fields (signature, name, title, date), and send a signing link to the vendor. The vendor secret goes to their email separately.

Vendor Signs

Vendor verifies email via OTP, reviews the document, and signs with recorded electronic consent. A SHA-256 hash of the signed PDF is stored. Any tampering breaks the chain.

Owner Counter-Signs

In dual-signing mode, you counter-sign to finalize. The fully executed PDF is watermarked with a QR code linking to public verification.

Bitcoin Attestation

The SHA-256 hash of the final watermarked PDF is anchored to Bitcoin via OpenTimestamps. Download a verification certificate. Anyone can check at /verify?sig= without trusting us.

Signing Modes

Three Ways to Execute

Dual signing

Vendor signs first. Owner counter-signs to finalize. Triggers watermark, QR verification link, and Bitcoin OpenTimestamps attestation.

Vendor only

Vendor signs and the contract is complete. Encrypted, watermarked, and audit-logged, but without owner counter-signature or blockchain attestation.

Owner only

Owner counter-signs from a prepared template. Useful when you need to execute a document on your own signature fields.

Attestation

Proof That Outlives the Platform

When you counter-sign, 1Bridge does not ask you to trust our audit log alone.

01Each signing stage stores a SHA-256 hash. The next stage must match the prior hash or the request is rejected.
02The final PDF is watermarked with 1Bridge · Blockchain-attested · Verify: … plus a QR code.
03OpenTimestamps anchors the document hash to a Bitcoin block. Confirmation email includes a link to download the verification certificate.
04Upload the PDF to /verify to confirm the hash matches the attestation, independently of 1Bridge.

Attestation applies when the owner counter-signs (dual-signing mode). Vendor-only completions are encrypted and audit-logged but do not trigger blockchain anchoring.

Same Vault

Sharing and Signing Share Infrastructure

Client-side encryption: signed PDFs stored as ciphertext

Three-factor vendor access: link, OTP, vendor secret

Watermark on every executed copy

Append-only audit log for all signing events

Team delegation for signing workflows

Instant revocation of pending requests

Positioning

vs Traditional E-Sign

vs DocuSign / Dropbox Sign: They store readable document copies on their servers and provide platform-controlled audit trails. 1Bridge stores ciphertext only and adds Bitcoin-anchored proof anyone can verify independently.

vs email PDF + scan: No consent record, no hash chain, no watermark, no revocation, no way to prove what was signed when.

Sign contracts with proof you can verify yourself

Join the waitlist, or try browser-based signing on the free tools page. No signup required.

Try free signing tools