Sign Documents Online with Blockchain Verification

Yes. Electronic signatures are legally binding in the United States under the ESIGN Act and UETA, in the European Union under eIDAS, and in most other jurisdictions worldwide. Chaindoc signatures meet the requirements of all three frameworks: every signing event is recorded with the signer's identity, timestamp, and a cryptographic hash anchored on the blockchain. Courts accept this certificate of completion as evidence of intent and document integrity.

Blockchain document signing means anchoring each signature event to a public blockchain so it cannot be altered after the fact. When you sign a document in Chaindoc, it generates a unique cryptographic hash of the file, links it to your verified identity and a timestamp, and writes that record to the blockchain. From that point on, anyone can verify that the file has not been changed and that you signed it at that exact moment, without trusting Chaindoc as a middleman. This is what makes the audit trail tamper-evident and court-admissible.

Chaindoc supports PDF, DOCX, PNG, and JPG. PDF is the recommended format for legally binding signatures because it preserves layout and supports embedded signature fields. DOCX files are converted to PDF on upload. You can also scan paper contracts with your phone camera: Chaindoc auto-detects edges, corrects perspective, and produces a signable PDF. Starting from a blank page? The contract templates cover NDAs, service agreements, and contractor agreements.

Yes. Chaindoc has a free tier that covers personal signing needs: your first document is free, no credit card required, and basic blockchain verification is included. Paid plans unlock higher signature volume, team workspaces, advanced KYC, custom branding, and API access. See the pricing page for current plan limits.

Yes. As long as the document hasn't been signed by all recipients, you can cancel the request instantly from the control panel. Once all parties have signed, the record is sealed on the blockchain and cannot be revoked.

No. For a standard signature, email verification is sufficient. If your document requires KYC-level assurance, you can enable identity confirmation for each signer. KYC verification is recommended for high-stakes contracts, financial agreements, and regulated workflows.

In the Completed Signatures section, you can view all recipients along with their exact signing timestamps. Each signing event is logged in the blockchain audit trail with the signer's identity, IP address, and timestamp, available for download as part of the certificate of completion.

Yes. Chaindoc records each action with a cryptographic timestamp on the blockchain, creating an immutable log that satisfies the requirements of the ESIGN Act (US), eIDAS (EU), and UETA. The resulting certificate of completion is accepted as court-admissible evidence of the signing event. Anyone holding the file can check it against that record with the PDF signature verifier.

Yes. After all signers complete the process, Chaindoc generates a certificate of completion containing the document hash, each signer's identity, timestamps, and the blockchain transaction ID. This package is downloadable and serves as tamper-proof evidence of the completed signing event.

Yes. Chaindoc runs the qualified signing flow and you bring the certificate. Signers authenticate through a remote signer redirect or an embedded interface using their national eID (Smart-ID, Mobile-ID, eParaksts, ID Austria and A-Trust, itsme, Chave Móvel Digital) or through any provider that speaks the Cloud Signature Consortium API. A one-shot QES is available for signers who don't already hold a certificate. One boundary worth stating plainly: Chaindoc isn't a trust service provider and doesn't issue qualified certificates. Yours comes from the QTSP; we run the signing session and the audit trail around it.