Master Signer

Master Legislativo

About this app

Master Signer is the ICP-Brasil digital signature tool for your mobile phone. Sign PDFs and legally valid documents in just a few taps, using your A1 certificate (e-CPF or e-CNPJ), with the security of your device's biometrics.

WHY MASTER SIGNER?
• ICP-Brasil legal validity — signatures recognized throughout Brazil.

• Truly simple — no Java, no applets, no plugins. Choose the document, the certificate, and sign.

• Your key never leaves your device — the A1 certificate is processed locally, protected by biometrics (fingerprint reader or facial recognition).

SIGNATURE FORMATS
• PAdES — the PDF is signed with a visible signature block, ready to send.

• CAdES — generates a package (.zip) with the document and the highlighted signature (.p7s).

FEATURES
• A1 certificate protected by password, stored in the device's secure vault.

• Biometric authentication before each signature.

• Share or save the signed document directly from the app.

• Signature verification — check the validity of already signed documents.

• Record of each signature with algorithm, origin, and date/time (audit trail).

• Your account panel: authorized domains, audit, and plan.

HOW IT WORKS
1. Import your A1 certificate once — it remains protected on the device.

2. Choose the document and format (PAdES or CAdES).

3. Confirm with your biometrics. Done: document signed and ready to share.

WHO IT'S FOR
Lawyers, accountants, public servants, healthcare professionals, and companies that need a legally valid ICP-Brasil digital signature — without depending on a computer.

IMPORTANT — RESPONSIBILITY
Master Signer is a tool that applies your signature to the document using your ICP-Brasil certificate. Legal validity stems from your digital certificate and how you use it. You are responsible for safeguarding your certificate and password, verifying the document before signing, and using the generated signatures. Master Legislativo Ltda. is not responsible for the content of signed documents or the legal consequences of signatures made by the user.

The certificate and password are never sent to our servers—they remain on your device.

Master Signer is a product of Master Legislativo Ltda.

Privacy: https://get.mastersigner.app/privacidade.html
Questions: [e-mail]