How to sign a PDF with an electronic signature

Sign any PDF with your .p12 certificate in the browser: no install, on mobile too. Step-by-step guide, free and compliant with Ecuadorian law.

By IDK Manager Team ·

How do you sign a PDF with an electronic signature in Ecuador? Open app.firmar.ec/sign, load your PDF and your .p12 certificate, type its password and sign. Everything happens in your browser —on mobile too— with no install; your key is never uploaded to any server. The signed PDF has the same legal validity as a handwritten signature (Law of Electronic Commerce, LCE 2002-67), as long as your certificate is from an Information Certification Entity (ECI) accredited by ARCOTEL.

What you need

  • A valid electronic signature certificate as a .p12 file (also called .pfx), issued by an ECI accredited by ARCOTEL. If you don’t have one yet, see how to get a certificate.
  • The PDF you want to sign.
  • A modern browser (Chrome, Edge, Firefox or Safari), on desktop or phone.

You don’t need Java, any installed program, or an extension.

Step by step

  1. Open the app. Go to app.firmar.ec/sign.
  2. Load the PDF. Drag or select the document you want to sign.
  3. Load your .p12 certificate and enter the password. The app checks that it comes from an ARCOTEL-accredited Ecuadorian ECI. The password and key are processed only on your device.
  4. Place the visible stamp (optional). You can position a stamp with your name, the issuing CA, the date and a verification QR code.
  5. Sign. The cryptographic computation happens in a dedicated Web Worker inside your browser.
  6. Download the signed PDF. The result is a PAdES signature (ETSI EN 319 142 standard), fully valid and verifiable.

Yes. In Ecuador an electronic signature made with a certificate from an ARCOTEL-accredited ECI has the same legal validity as a handwritten signature (LCE 2002-67). Anyone can verify the signed PDF to confirm its integrity and the certificate’s validity.

Specific cases

  • Your certificate is from the Central Bank (BCE): follow the guide to sign with a BCE certificate.
  • You need to sign SRI electronic tax documents (XAdES): that requires the XAdES format; use FirmaEC. See the firmar.ec vs FirmaEC comparison.
  • Your certificate is on a physical USB token (not a .p12 file): today firmar.ec signs with the .p12 file; for a physical token use FirmaEC.

Frequently asked questions

Do I have to upload my PDF or certificate to the internet? No. The whole process is local in your browser; nothing is sent to a server.

Does it work on mobile? Yes, firmar.ec is a mobile-first PWA; it works on iOS and Android.

How much does it cost? Signing is free. firmar.ec is a non-profit open-source project by IDK Manager.