> For the complete documentation index, see [llms.txt](https://docs.emudhradigital.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.emudhradigital.com/documentation/esign-and-signing-services-overview.md).

# eSign and Signing Services Overview

eMudhra is a licensed Certifying Authority (CA) under the Controller of Certifying Authorities (CCA), India, and an empanelled **eSign Service Provider (ESP)**. This documentation covers the family of signing services eMudhra provides on top of that trust infrastructure — from one-click Aadhaar-based eSign to long-term remotely held keys and fully automated organisational signing.

All signatures created through these services are digital signatures under the Information Technology Act, 2000 (Second Schedule) and are legally equivalent to handwritten signatures for the purposes permitted by the Act.

## Products covered

| Product                                                                                                               | What it does                                                                                                                                                      | Typical users                                                                                    |
| --------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------ |
| [**eSign v2 (Online Aadhaar eKYC)**](/documentation/esign-v2-online-aadhaar-ekyc/esign-v2-overview.md)                | On-demand signing with a one-time DSC after Aadhaar authentication by OTP, fingerprint, iris or face. No enrolment needed.                                        | Banks, NBFCs, insurers, fintechs, government services signing customer forms                     |
| [**eSign v3 (CA eKYC Account)**](/documentation/esign-v3-ca-ekyc-account/esign-v3-overview.md)                        | Signing with a one-time DSC backed by an eKYC account held with eMudhra (offline Aadhaar, PAN, bank or organisational KYC). Authenticated by PIN + second factor. | Users without Aadhaar-linked mobile, organisational signatories, NRIs, foreign nationals         |
| [**Remote Key Storage**](/documentation/remote-key-storage/remote-key-storage-overview.md)                            | A long-term DSC whose private key lives in an eMudhra HSM, unlocked with the signer's AuthPIN.                                                                    | Professionals and executives who sign frequently — CAs, CSs, directors, doctors, approvers       |
| [**Remote Signing (Document Signer)**](/documentation/remote-signing-document-signer/remote-signing-overview.md)      | Automated, unattended signing of documents with an organisation's Document Signer Certificate held in an eMudhra-hosted HSM.                                      | Bulk statements, invoices, certificates, degree certificates, e-stamps, system-generated letters |
| [**Digital Signature Validation Tool**](/documentation/digital-signature-validation-tool/validation-tool-overview.md) | Verifies signatures on PDF, XML and CMS/PKCS#7 data — integrity, certificate chain, revocation and timestamp.                                                     | Relying parties, back-office verification teams, auditors, portals accepting signed uploads      |

## How the documentation is organised

<table data-view="cards"><thead><tr><th></th><th></th></tr></thead><tbody><tr><td><strong>Getting Started</strong></td><td>Concepts, regulatory framework, architecture and how to choose the right product.</td></tr><tr><td><strong>Product guides</strong></td><td>One section per product with flows, API specifications and error codes.</td></tr><tr><td><strong>Onboarding</strong></td><td>How to become an Application Service Provider (ASP) and go live.</td></tr><tr><td><strong>Reference</strong></td><td>Security and compliance controls, FAQ and links to CCA source documents.</td></tr></tbody></table>

## Why eMudhra

* **Licensed CA and empanelled ESP** — key generation, certificate issuance and signing are performed in-house under CCA audit.
* **Every eSign variant** — Aadhaar OTP, fingerprint, iris and face authentication (API 2.1), CA eKYC accounts (API 3.x) and Remote Key Storage (eSign Remote API).
* **Flexible integration** — browser redirect, Web-to-App, App-to-App and embeddable mobile SDKs, plus the emSigner gateway for organisations that do not want to register as an ASP.
* **Globally trusted roots** — emSign roots are part of the Adobe Approved Trust List (AATL) and Microsoft Trusted Root Program, so signatures validate natively in Adobe Acrobat and Microsoft Office.
* **Compliance by design** — FIPS 140-3 Level 3 HSMs, ISO 27001-certified data centres in India, WebTrust audits and 7-year evidence retention.

{% hint style="info" %}
This documentation follows the CCA *e-Authentication Guidelines for eSign* (v1.9) and the published eSign API specifications (API 2.1, API 3.3, eSign Remote API 1.1). See [Regulatory Sources](/documentation/support-and-reference/regulatory-sources.md).
{% endhint %}