Question 1

Is Abundera Sign legally binding?

Accepted Answer

Yes. Abundera Sign complies with the Electronic Signatures in Global and National Commerce Act (ESIGN Act, 15 U.S.C. § 7001) and the Uniform Electronic Transactions Act (UETA), which together make electronic signatures legally equivalent to wet-ink signatures in all 50 U.S. states. Every signature includes a hash-chained audit trail, RFC 3161 trusted timestamp, and PAdES digital signature, providing stronger evidence than a pen-and-paper signature.

Question 2

How is this different from DocuSign or HelloSign?

Accepted Answer

Most e-signature platforms tell you a document was signed. Abundera Sign proves it. Every envelope includes a SHA-256 hash-chained audit trail, an RFC 3161 trusted timestamp from an independent authority, a PAdES digital signature embedded in the PDF, optional GitHub evidence anchoring, and a Certificate of Completion with cryptographic proof, all verifiable without an Abundera account. We also offer SMS OTP verification, geography locking, VPN/proxy blocking, and a Court-Ready Declaration for litigation.

Question 3

What is an RFC 3161 trusted timestamp?

Accepted Answer

An RFC 3161 timestamp is a cryptographic proof issued by an independent Timestamp Authority (TSA) that certifies your document existed at a specific point in time. Unlike a server clock (which the platform controls), a trusted timestamp comes from a third party and cannot be backdated. This is critical for proving when a document was signed, not just that it was signed.

Question 4

What is a PAdES digital signature?

Accepted Answer

PAdES (PDF Advanced Electronic Signatures) is an international standard for digitally signing PDF documents. Abundera Sign embeds a PAdES-LTA (Long-Term Archival) signature into every sealed PDF using an AATL-certified HSM-backed signing certificate. This includes a Document Security Store (DSS) with the signing certificate chain, embedded OCSP responses, and a Document Timestamp from an independent TSA, ensuring the signature remains verifiable indefinitely, even after the original signing certificate expires. Adobe Acrobat displays a green checkmark confirming the signature's validity and trust, no manual certificate installation required. Verifiable in any PDF reader that supports digital signatures, no Abundera account required.

Question 5

Can I verify a signed document without an account?

Accepted Answer

Yes. Anyone can verify a signed document at sign.abundera.ai/verify by entering the envelope ID or uploading the PDF. The verification page shows the complete audit chain, signer details, hash integrity, timestamps, and digital signature, all publicly accessible. You can also verify the PAdES signature directly in Adobe Acrobat.

Question 6

How does the hash-chained audit trail work?

Accepted Answer

Every event in the signing process (created, viewed, signed, completed) is recorded as an audit entry. Each entry’s SHA-256 hash includes the previous entry’s hash, forming an unbreakable chain. If anyone modifies or deletes a single event, every subsequent hash becomes invalid, making tampering immediately detectable. This is the same principle behind blockchain technology.

Question 7

Do you offer SMS verification?

Accepted Answer

Yes. On Professional and Business plans, you can require signers to verify their phone number via SMS one-time password (OTP) before signing. This adds a second factor of authentication beyond email, strengthening signer identity verification. Each signer gets up to 3 SMS sends with a 60-second cooldown.

Question 8

What happens if a signed document is disputed in court?

Accepted Answer

Abundera Sign is designed to produce a stronger evidentiary record than standard e-signature workflows. Your signed PDF includes a Certificate of Completion, Cryptographic Proof page, and embedded PAdES-LTA digital signature with 8 verification layers (5 independent external anchors plus 3 internal integrity measures). The hash-chained audit trail, dual RFC 3161 timestamps, GitHub evidence anchor, Bitcoin blockchain anchoring, and SHA-256 + SHA-512 dual hashes create independent, third-party proof that is materially harder for any one party to falsify. Professional and Business plan subscribers can also generate a 13-section Declaration of Custodian of Records, a formal sworn declaration under 28 U.S.C. § 1746.

Question 9

What does the Declaration of Custodian of Records include?

Accepted Answer

The declaration is a 13-section sworn PDF document with a 26-term technical glossary, digitally signed by Abundera with a PAdES-LTA signature. It covers: named declarant with personal knowledge statement, platform security measures including 8 verification layers, document details, signing process and email link delivery, per-signer authentication evidence with signer evidence scoring, audit chain integrity verification, cryptographic hashes and anchors including dual RFC 3161 timestamps and Bitcoin blockchain proof, data integrity and WORM immutability, public verification with QR code, system reliability under FRE 901(b)(9), records custodian statement citing FRE 803(6), 902(11), and 902(14), declaration under penalty of perjury per 28 U.S.C. § 1746, and venue for challenges.

Question 10

Do you charge per user?

Accepted Answer

No. Abundera Sign charges per envelope, not per seat. Each plan includes a generous number of users, Starter includes 2 users, Professional includes 5, and Business includes 15. Additional users can be added at a low per-user cost ($10, $8, or $5/mo respectively). There are no hidden fees and no annual contracts required.

Question 11

Can I use the API to send documents programmatically?

Accepted Answer

Yes. Every plan includes full API access. Create envelopes, manage templates, check status, download signed PDFs, and receive HMAC-signed webhooks on every event, all with a single API call. See the docs for examples.

Question 12

How long are signed documents stored?

Accepted Answer

Retention depends on your plan: Starter includes 3 years, Professional includes 7 years, and Business includes customizable retention up to 99 years. Documents are stored in write-once immutable storage on Cloudflare’s global infrastructure. Once sealed, the evidence package cannot be modified without invalidating the hash chain.

Question 13

What templates are available?

Accepted Answer

Abundera Sign includes 1,000+ ready-to-use templates across 30+ categories including real estate, employment, corporate, finance, healthcare, technology, creative, and more. All plans include access to the full template library. Business plan subscribers can also create and manage custom templates via the API.

Question 14

What are the Audio and Video Statement features?

Accepted Answer

Audio and Video Statements are optional biometric verification features available on Professional and Business plans. When enabled, the signer is prompted to record themselves reading a sworn statement aloud. Audio captures voice biometrics (50–100KB), while Video captures both face and voice (500KB–2MB). Recordings are stored as part of the tamper-evident evidence package with SHA-256 hashes.

Question 15

What are Signing Links, Delegation, Embedded Signing, and In-Person Signing?

Accepted Answer

Signing Links (Professional+) let you create a reusable URL, each visitor gets their own envelope, perfect for waivers or onboarding forms. Signer Delegation allows a signer to hand off signing authority to someone else, with a full audit trail and chain limit. Embedded Signing lets you embed the signing experience in your own app via iframe with postMessage callbacks. In-Person Signing enables kiosk mode for face-to-face signing on a shared device, each signer sees only their own fields.

更强的记录比它们所防止的纠纷成本低得多

按量付费

企业版与白标

按次付费附加功能（专业版及以上）

验证附加包

一份有争议的合同到底要花多少钱

比较证据深度，而不仅仅是签名收集

一次 API 调用，仅此而已。

常见问题解答

准备开始了吗？