---
title: "PAdES signatures"
description: "PAdES PDF signatures in PKI SDK with the PadesSigner class, following the ETSI 102778 specification, with a basic signature example."
canonical: "https://docs.lacunasoftware.com/en-us/articles/pki-sdk/signatures/pades"
locale: "en"
product: "PKI SDK"
last_updated: "2026-10-12"
---

# PAdES signatures

The PAdES standard sets the rules for signing PDF files. In the SDK, the @Lacuna.Pki.Pades.PadesSigner class is the central
object that creates PDF signatures following the ETSI 102778-x specification.

## Basic signature example

The code below shows a basic PAdES signature, to introduce and exercise the concepts and properties of this signer.

```cs
// Instantiate the signer object, which creates the signature
var signer = new PadesSigner();

signer.SetSigningCertificate(signingCert);    // the signer's certificate, with its private key
signer.SetPdfToSign(pdfBytes);                // bytes or stream of the PDF document to sign
signer.SetPolicy(PadesPolicySpec.GetBasic()); // basic policy, with the Windows roots as TrustArbitrators
signer.ComputeSignature();                    // creates the attributes and gets the signer's signature

byte[] signedPdf = signer.GetPadesSignature();      // returns the bytes of the signed PDF
```

**Demos and samples**

- Live demo: [Sign a file with your certificate](https://try.lacunasoftware.com/en/pki-suite/sign-a-file)
- Live demo: [Validate a signed file](https://try.lacunasoftware.com/en/pki-suite/validate-a-signed-file)
- Live demo: [Make a printer-friendly version](https://try.lacunasoftware.com/en/pki-suite/printer-friendly-version)
- Sign a PDF with PKI SDK: [.NET](https://github.com/LacunaSoftware/PkiSuiteSamples/blob/master/dotnet/mvc/PkiSuiteAspNetMvcSample/Controllers/PadesSignatureSdkController.cs)
- Sign a file with CAdES using PKI SDK: [.NET](https://github.com/LacunaSoftware/PkiSuiteSamples/blob/master/dotnet/mvc/PkiSuiteAspNetMvcSample/Controllers/CadesSignatureSdkController.cs)
- Validate a signed PDF using PKI SDK: [.NET](https://github.com/LacunaSoftware/PkiSuiteSamples/blob/master/dotnet/mvc/PkiSuiteAspNetMvcSample/Controllers/OpenPadesSignatureSdkController.cs)
- Validate a CMS/CAdES signature using PKI SDK: [.NET](https://github.com/LacunaSoftware/PkiSuiteSamples/blob/master/dotnet/mvc/PkiSuiteAspNetMvcSample/Controllers/OpenCadesSignatureSdkController.cs)
- Validate a signed XML using PKI SDK: [.NET](https://github.com/LacunaSoftware/PkiSuiteSamples/blob/master/dotnet/mvc/PkiSuiteAspNetMvcSample/Controllers/OpenXmlSignatureSdkController.cs)
- Sign multiple PDFs with PKI SDK: [.NET](https://github.com/LacunaSoftware/PkiSuiteSamples/blob/master/dotnet/mvc/PkiSuiteAspNetMvcSample/Controllers/BatchPadesSignatureSdkController.cs)
- Sign a PDF with a server key using PKI SDK: [.NET](https://github.com/LacunaSoftware/PkiSuiteSamples/blob/master/dotnet/mvc/PkiSuiteAspNetMvcSample/Controllers/PadesServerKeySdkController.cs)
- Make a printer-friendly version of a signed PDF using PKI SDK: [.NET](https://github.com/LacunaSoftware/PkiSuiteSamples/blob/master/dotnet/mvc/PkiSuiteAspNetMvcSample/Controllers/PrinterFriendlyPadesSdkController.cs)
- Sign a medical prescription (Receita Simples) using PKI SDK: [.NET](https://github.com/LacunaSoftware/PkiSuiteSamples/blob/master/dotnet/mvc/PkiSuiteAspNetMvcSample/Controllers/ReceitaSimplesSdkController.cs)