--- title: "DataHubz Attest | Sign documents you can prove" description: "Send documents for signature with passkeys and end-to-end encryption. Every signed copy carries its own proof. 2 documents free in total, then $5 a month." url: https://attest.datahubz.com updated: 2026-10-24 --- # Sign documents you can prove. Send a PDF for signature, or sign one you've been sent. Every signer approves with a passkey, the document stays end-to-end encrypted, and the signed copy carries its own proof: anyone can check it, even if Attest is gone. [Send your first document free ](https://attest.datahubz.com/signin?product=sign) [How signing works](https://attest.datahubz.com/sign) 2 documents free in total, then $5 a month for 20. The people who sign never pay. No credit card. ![](https://attest.datahubz.com/demo/attest-sign-v5-poster.jpg) Watch how signing works · 2:23 · sound on · captions available ## What the people you send it to see. Nothing to install, no account to create, no password, nothing to pay. 1. 1 An email with their own link It names you, the document and your note. The link is theirs alone. 2. 2 One passkey prompt Face ID, Touch ID, Windows Hello or their device PIN sets up their key. Nothing else to create. 3. 3 Ready now, or unlocked by you The first time they sign with Attest, you choose. With Ready now, the document opens as soon as they set up their passkey. With Private from the start, your own devices unlock it for them automatically, usually within seconds when one of them is online with notices allowed (a computer, with its browser running). If none has done it within 15 minutes, we email you and you unlock it with your passkey. 4. 4 Guided to every field They review the document, fill in what you asked for, and approve with their passkey. 5. 5 The same sealed copy as you The signed pages, with a stamp on each signature and a seal line on each page, the certificate, the audit trail and a "Verify it yourself, without us" page, with the evidence, the original and a verifier inside. ## Why sign with Attest. A signing experience people already know, with evidence you keep, and terms that stay yours. Your terms stay yours Every document is end-to-end encrypted, and you choose how private: Private from the start means only you and your signers can ever open it; Ready now lets a new signer open it right away, end-to-end encrypted from the moment they do. Only fingerprints go on the blockchain. Proof that doesn't need us Every signer approves with a passkey. Each signed copy carries the evidence and a verifier: anyone can check the signatures, the document and when it was sealed, even if Attest is gone. Prove a fact, keep the rest Need to show you signed with Acme, and the day it was completed? Share a zero-knowledge proof of exactly that. The document, its title and its terms stay private. ### Everything you send documents with - Signature, initials, date, full name and text fields - Sign in any order, or one signer at a time - Automatic reminders and expiry dates - Sign a document someone sent you, and send it back - A Signed with Attest stamp on every signature - Download the signed pages alone, for filings - Decline, void and an audit trail of every step - Organizations: one plan for the whole team - Free verification for anyone, no account ## Simple pricing. The people who sign never pay, on any plan. Free $0 - 2 documents sent for signature, in total - Sealed copies, certificates and Share proof - Every signing feature, free verification [Start free](https://attest.datahubz.com/signin?product=sign) Signing $5 a month - 20 documents a month - Everything Free includes - Cancel any time [Start with 2 free](https://attest.datahubz.com/signin?product=sign) Pro $49 a month - Every Attest tool, signing included - Receipts, Proof Cards, sealed documents, Verified Forms - The API, with 10,000 records a month [See Pro](https://attest.datahubz.com/signin) ## One place for the things that need proof. Contracts and approvals, credentials, confidential documents, and the questions you need honest answers to. Every tool leaves evidence that anyone can verify and no one can quietly change. ### Evidence [ Agreements Send a document for signature to up to 20 signers, in any order. Signed with passkeys, encrypted end to end, anchored when complete.ContractsNDAsApprovalsPoliciesHow it works ](https://attest.datahubz.com/docs/api#agreements) [ Receipts Turn a file, an event, or an AI agent's action into a receipt anyone can verify later, without ever receiving the file.DeliverablesPhotosDecisionsBuildsHow it works ](https://attest.datahubz.com/docs/api#receipts) [ Zero-knowledge proofs Prove a fact about a signed agreement, like who it was with and when, without revealing the document.Due diligencePartnershipsComplianceHow it works ](https://attest.datahubz.com/docs/api#proofs) ### Credentials [ Proof Cards Issue credentials people carry and prove anywhere, revealing only the fields they choose. Suspend or revoke at any time, and anyone who checks the card sees it.TrainingSupplier approvalMembershipEmploymentHow it works ](https://attest.datahubz.com/docs/api#cards) [ Certificates Certify that an organization passed an assessment or met a standard. Signed by your experts' passkeys and by your organization, anchored, and checked by anyone from its PDF.Security assessmentsAuditsComplianceCompletionHow it works ](https://attest.datahubz.com/docs/api#certificates) ### Confidential [ Sealed submissions Collect bids, proposals, or applications that no one can open before your deadline, not even you or Attest.TendersRFPsGrant callsHiringHow it works ](https://attest.datahubz.com/docs/api#sealed) [ Approval release A document that opens for chosen people only after enough approvers sign off, like 2 of 3, and not before a date if you set one.Board papersPayoutsEmbargoed resultsHow it works ](https://attest.datahubz.com/docs/api#releases) [ Continuity vault Access details, instructions, and documents kept sealed, released to the right people only if you stop checking in and your trustees confirm.HandoversTreasury accessKey-person riskHow it works ](https://attest.datahubz.com/docs/api#vaults) ### Collect [ Verified Forms Ask a group and get honest answers. Each one is proven to come from someone on your list, once, without revealing who.Team pulsesCommittee votesMember feedbackHow it works ](https://attest.datahubz.com/docs/api#forms) ## The guarantees of Web3, the user experience of Web2. WalletsGas feesBridgesSeed phrasesTokens to buyBlock explorers Attest does all of that for you, automatically. You and your users work like in any other app. Behind every click, Attest performs each step a blockchain requires, correctly and on the record. You do - Upload a document - Sign with your fingerprint - Or call the API Attest does, automatically running - Creates a wallet for every user - Pays every transaction's gas - Swaps funds for gas - Keeps keys encrypted, end to end - Anchors each record on-chain - Submits proofs for verification Base mainnet Records and signatures, anchored from each user's own wallet zkVerify Zero-knowledge proofs, independently verified Public verification Anyone can check it, free, forever ## A signed copy that proves itself. Every Attest signed copy carries its evidence and an open verifier, and its pages are anchored on a public blockchain: change one word and it fails. Every credential, sealed document and answer gets the same cryptographic evidence, which anyone can check and no one can forge, including us. ### Every signer approves with a passkey. Anyone can check it. Each signature is bound to the signer's passkey and their own secret key, unlocked by Face ID, Touch ID, Windows Hello or the device PIN. It's recorded with the document's fingerprint and the exact time, then anchored on a public blockchain from the signer's own wallet. Anyone can check who signed what, and when. - Unforgeable: it takes a passkey only the signer controls - Tamper-evident: change one byte and verification fails [How it works ](https://attest.datahubz.com/docs/api#agreements) ### A permanent receipt for anything that matters. Contracts, photos, recordings, board decisions, what an AI agent did and who authorized it, the build you shipped. Attest turns each into a receipt anyone can verify later, without ever receiving the file itself. - Prove a file existed, unchanged, at a point in time - Corrections supersede, nothing is ever erased [How it works ](https://attest.datahubz.com/docs/api#receipts) ### Prove it's true. Reveal nothing else. Show that a statement is true, like “we have a signed agreement with Acme, completed in September”, without disclosing the document, its terms, or anyone else involved. For deals, partnerships, and compliance where confidentiality, privacy, and secrecy are not negotiable. - Standard Groth16 proofs, checked independently on zkVerify - You choose exactly what a proof reveals [How it works ](https://attest.datahubz.com/docs/api#proofs) ### Credentials people carry, and you can take back. Issue a card for a completed training, an approved supplier, a membership, or a job. Your organization signs it; the holder shares only the fields they choose, as a link, a QR code, or from a wallet app. Suspend or revoke it any time, and anyone who checks the card sees it. Or publish a certificate that a company passed your assessment: signed by your experts and your organization, and found by anyone who drops its PDF on the verifier. - W3C Verifiable Credentials, also as SD-JWT for wallet apps - Every issuance and status change anchored on Base [How it works ](https://attest.datahubz.com/docs/api#cards) ### Information that opens only when it should. Collect bids that stay sealed until the deadline. Release board papers once 2 of 3 directors approve. Keep treasury access and handover instructions ready for the right people if you stop checking in. The condition is enforced by cryptography: files are encrypted in your browser, keys are split or time-locked, and Attest holds the files only as ciphertext. - Time locks from drand, run by independent operators - Keys split so it takes as many approvers or trustees as you set [How it works ](https://attest.datahubz.com/docs/api#sealed) ### Honest answers, from exactly the right people. Ask your team, a committee, or your members. Each answer comes with a zero-knowledge proof that it's from someone on your list, and that nobody answered twice, without revealing who. Answers are sent without any sign-in, so nothing stored links an answer to a person. Anyone can re-check the results. - Built on Semaphore; every proof verified on zkVerify - Eligibility by email list, organization, or Proof Card [How it works ](https://attest.datahubz.com/docs/api#forms) ### Your files are decrypted only in the parties' browsers, and you choose how private. Documents are encrypted on your device before upload, and decrypted only in the browsers of the people you share them with, unlocked by their passkeys. We store each document only as ciphertext, and you choose how private. With Private from the start, no one but you and your signers can ever open it: not our staff, not our cloud provider, not an attacker who breaks in. Ready now lets a new signer open it right away, end-to-end encrypted from the moment they do; it keeps a sealed copy of the document's key with our signing service until the signer first opens it, then deletes that copy. Before anything is encrypted to someone, your browser checks their key against a public key directory anchored on Base, so not even a key swapped in by Attest would be used. Verifiable forever Records live on a public blockchain. If DataHubz disappeared tomorrow, every one would still verify. Corrections, not deletions Amend with a superseding record. Every correction is part of the tamper-evident trail. Private by design Attest stores your documents only as ciphertext, and with Private from the start, no one but you and your signers can ever open them. Only fingerprints and commitments go on the blockchain, and proofs reveal only what you choose. ## Anyone can verify. No account, no cost. Hand someone a receipt, a certificate, a Proof Card, or a proof. They check it on Attest in seconds, or on the blockchain themselves, without trusting us. [Open the verifier ](https://attest.datahubz.com/verify) Receipts By receipt ID, fingerprint, or by dropping the original file. It's hashed in your browser, never uploaded. Proof Cards Open a shared card to see who issued it, that it's unchanged, and whether it's still valid right now. Signed agreements A public certificate of who signed and when, if the owner allows it. The document itself stays private. Zero-knowledge proofs Check a proven statement, like an agreement with a company, when the agreement itself is kept private. ## Machine-ready on top. Every Web3 requirement underneath. - Every user has their own wallet; every transaction is sent and paid from it - Gas is funded automatically from a treasury, so no one ever holds crypto - Passkeys follow the WebAuthn standard, with the PRF extension for key unlock - Documents are encrypted end to end; keys never leave the browser unencrypted - Zero-knowledge proofs are Groth16, verified on zkVerify mainnet - Compliance proofs run on the Hubz VCE security-scan circuit - Records are anchored on Base mainnet, and each anchor names its wallet - Proof Cards are W3C Verifiable Credentials and SD-JWT VCs, delivered to wallets over OpenID4VCI - Time locks use drand, randomness published by a threshold of independent operators - Keys are split with Shamir's secret sharing, so fewer than the set number can't open - Anonymous answers use Semaphore proofs, each also verified on zkVerify ### Everything in the dashboard, as an API. Receipts, agreements, zero-knowledge proofs, Proof Cards, certificates, sealed calls, releases, vaults, verified forms, and verification. Hash locally, send the fingerprint, get permanent proof. Batched anchoring keeps it at a fraction of a cent. attest api # create a receipt for an AI agent action POST /api/v1/receipts { "kind": "agent_action", "sha256": "9f86d0…" } # send an end-to-end encrypted agreement POST /api/v1/agreements # prove a fact about it in zero knowledge POST /api/v1/agreement-proofs # issue a Proof Card to a person POST /api/v1/credentials # certify that a company passed an assessment POST /api/v1/certificates # anyone verifies, no key needed POST /api/v1/verify [Explore the API ](https://attest.datahubz.com/docs/api) [Create an API key](https://attest.datahubz.com/signin) ## Built on public infrastructure and open standards. [![DataHubz](https://attest.datahubz.com/brand/datahubz-logo-black.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)![DataHubz](https://attest.datahubz.com/brand/datahubz-logo-white.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)Builds and operates Attest](https://www.datahubz.com) [![Hubz VCE](https://attest.datahubz.com/brand/hubz-vce-logo-black.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)![Hubz VCE](https://attest.datahubz.com/brand/hubz-vce-logo-white.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)The zero-knowledge circuit behind compliance proofs](https://vce.datahubz.com) [![Base](https://attest.datahubz.com/brand/base-logo-black.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)![Base](https://attest.datahubz.com/brand/base-logo-white.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)Blockchain where every record is anchored](https://base.org) [![zkVerify](https://attest.datahubz.com/brand/zkverify-logo-black.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)![zkVerify](https://attest.datahubz.com/brand/zkverify-logo-white.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)Verification of every zero-knowledge proof](https://zkverify.io) ### Open standards [![WebAuthn logo](https://attest.datahubz.com/standards/webauthn.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)WebAuthnW3C standardPasskeys: every signature and sign-in, with Face ID, Touch ID, Windows Hello or the device PIN](https://www.w3.org/TR/webauthn/) [![Verifiable Credentials 2.0 logo](https://attest.datahubz.com/standards/w3c.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)Verifiable Credentials 2.0W3C standardProof Cards: credentials that reveal only the fields the holder chooses](https://www.w3.org/TR/vc-data-model-2.0/) [![Bitstring Status List logo](https://attest.datahubz.com/standards/w3c.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)Bitstring Status ListW3C standardRevocation and suspension anyone can check, with every change anchored](https://www.w3.org/TR/vc-bitstring-status-list/) [ Open Badges 3.01EdTech standardTraining cards in the format learning platforms and badge wallets read](https://www.imsglobal.org/spec/ob/v3p0/) [![SD-JWT VC logo](https://attest.datahubz.com/standards/ietf.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)SD-JWT VCIETF standardEvery card also in the wallet-ready format of the DIIP profile, with Token Status Lists](https://datatracker.ietf.org/doc/draft-ietf-oauth-sd-jwt-vc/) [![OpenID4VCI and OpenID4VP logo](https://attest.datahubz.com/standards/openid.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)OpenID4VCI and OpenID4VPOpenID FoundationCards move into wallet apps and are presented from them, with holder binding](https://openid.net/sg/openid4vc/) [![Web Cryptography API logo](https://attest.datahubz.com/standards/w3c.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)Web Cryptography APIW3C standardDocuments encrypted in your browser with AES-256-GCM and RSA-OAEP](https://www.w3.org/TR/WebCryptoAPI/) [NISTSHA-256NIST FIPS 180-4The fingerprint behind every receipt, computed on your device](https://csrc.nist.gov/pubs/fips/180-4/upd1/final) [ Groth16Peer-reviewed zk-SNARKZero-knowledge proofs that reveal one fact and nothing else](https://eprint.iacr.org/2016/260) [![Semaphore logo](https://attest.datahubz.com/standards/semaphore.svg?dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)SemaphoreOpen protocol, Ethereum Foundation (PSE)Verified Forms: anonymous answers, each proven to come from someone on the list, once](https://semaphore.pse.dev) [![drand logo](https://attest.datahubz.com/_next/image?url=%2Fstandards%2Fdrand.png&w=2048&q=75&dpl=dpl_8LTk6FWhP9KGN9e3fjwjaPZQXjRL)drandLeague of EntropyTime locks: sealed submissions and release dates that open only when the moment comes](https://drand.love) [ISO/IECShamir's Secret SharingISO/IEC 19592-2:2017Approval release and continuity vaults: keys split so it takes the approvals you set](https://www.iso.org/standard/65425.html) ## Give your agreements, credentials, and decisions proof anyone can check. Free to start. No wallets, no crypto, no setup beyond your email. [Start free](https://attest.datahubz.com/signin) [ Read the docs](https://attest.datahubz.com/docs) --- Source: https://attest.datahubz.com