Frequently Asked Questions
Common questions about Mark, answered plainly.
What is Mark?
Mark is a sovereign digital signing protocol and app. You sign documents with a cryptographic signature that anyone can verify — without depending on any platform, company, or certificate authority.
How is Mark different from DocuSign?
DocuSign owns the verification — if DocuSign goes away, your signatures become unverifiable. Mark produces self-contained proof packages (SignedBundles) that verify against public math, public blockchains, and published cryptography. No server required. See Sovereignty Model for details.
Are Mark signatures legally binding?
Yes, in most jurisdictions. Mark signatures qualify as electronic signatures under the US ESIGN Act, EU eIDAS (Advanced Electronic Signature level), and equivalent frameworks in Canada, India, and most common-law countries. See Legal Standing for a detailed analysis.
What happens if I lose my phone?
Your signing subkey is on the lost device, but your root key identity survives. If you have a YubiKey, tap it on your new phone to revoke the compromised subkey and issue a new one. If you used software-only keys, your root key is on the lost device — this is why we recommend YubiKey for high-stakes signing.
Do I need an internet connection to sign?
No. Signing happens entirely on-device. The signature is valid immediately. Internet is needed only for publishing your identity on-chain, timestamping, and generating verification codes — all of which can happen later.
What can I sign?
Any file. Mark signs the SHA-256 hash of the file, so it works with PDFs, images, spreadsheets, code, plain text — anything. The file never leaves your device.
Do verification codes expire?
Yes. Verification codes are a convenience layer — they expire after 30 days. The underlying SignedBundle and all cryptographic proofs are permanent. You can always share the bundle file directly.
Is Mark quantum-safe?
Not yet. Mark uses Ed25519, which is vulnerable to quantum attacks. Post-quantum signature algorithms (likely ML-DSA / Dilithium) are planned for MSP v2. Current signatures will remain verifiable — the migration will add a parallel quantum-resistant signature, not replace the existing one.
How much does Mark cost?
The Mark app is free for individual use. The protocol is open. Enterprise features (organization management, bulk signing, audit trails) are planned as paid tiers.
Are my signatures stored on the blockchain?
The cryptographic proof is — not the document itself. When you sign a document, Mark publishes the proof chain (document hash, signer fingerprint, timestamps, and signature metadata) to the Polygon blockchain via the MarkSignatureBundleRegistry contract. The original document never leaves your device and is never uploaded anywhere.
This means anyone can independently verify that a signature existed at a specific block timestamp by querying Polygon directly — no Mark server required.
Is Mark open source?
The Mark Signing Protocol specification and the verification logic are open. The mobile app source is not currently open but may be in the future. Anyone can build a compatible client — the protocol is the product.