Digital certificate A1 or A3: which one to choose?
A1 is a file saved on your computer — simpler and cheaper, but tied to that one device. A3 lives on a token, card, or in the cloud — you can use it anywhere and it is more secure. For maximum convenience, BirdID is the A3 that lives on your phone, with no physical hardware required.
What is an A1 certificate?
The A1 is a digital file — usually with a .pfx extension — that you install directly on your computer.
It works like a key stored on that specific device.
It is the simplest option to install and the most affordable. It works well for people who use their certificate infrequently and always on the same computer.
Main limitation: the certificate is tied to one device. If your computer breaks, gets reformatted, or you switch machines, the certificate is lost. You can export and reinstall it, but it takes effort — and many people forget to make a backup.
What is an A3 certificate?
The A3 stores the cryptographic key on a separate secure device: a USB token, a smart card, or the cloud (in the case of BirdID). The key never leaves the device — this makes A3 more secure than A1.
With A3, you can use your certificate on any computer. Just plug in the token or open the app. It is the choice for anyone who needs mobility or signs documents frequently.
What is the practical difference?
| A1 | A3 (token/card) | A3 BirdID (cloud) | |
|---|---|---|---|
| Where it lives | On your computer | On a token or card | On your phone (app) |
| Portability | Any PC (with the .pfx file + PIN) | Any computer | Any smartphone |
| Security | Medium | High | High |
| Risk of loss | Reformat / broken PC / loss of the .pfx file | Losing the token | Minimal (cloud) |
| e-CPF price (12 months) | R$ 144.00 | From R$ 144.00 | R$ 149.90 |
| Hardware required | Computer (desktop or laptop) | Token and card + reader | Smartphone (any operating system) |
BirdID: A3 without hardware
BirdID is a cloud-based A3 certificate. You install the app on your phone, go through a video call of about 5 minutes to issue the certificate for the first time, and that is it — your certificate lives in the app.
From then on, you can sign documents, access Brazilian government systems, and renew the certificate directly from your phone or computer, with no physical token. Future renewals are done through the app itself, with no new video call required.
When to choose A1
- You use your certificate infrequently
- You always work on the same computer
- You want the most affordable option
- You do not need to sign documents on the go
When to choose A3 or BirdID
- You use your certificate frequently
- You work on more than one computer or location
- You want to renew without bureaucracy in future years
- You do not want to risk losing the certificate to a reformat
- You prefer not to carry a physical token
Frequently asked questions
- Can I use an A1 certificate on more than one computer?
- Not directly. The A1 is a file installed on a specific computer. You can export the .pfx file and install it on another machine, but it is tied to one device at a time.
- What happens if I lose my A3 token?
- The certificate becomes inaccessible. You will need to revoke the current certificate and issue a new one. BirdID is a safer alternative: the certificate lives in the cloud, linked to your phone, with no risk of physical loss.
- Is BirdID a type of A3 certificate?
- Yes. BirdID is a cloud-based A3 certificate. Instead of being stored on a physical token or card, it is securely stored in an app on your phone.
- Which type do accountants and lawyers use most?
- Professionals who sign many documents usually prefer A3, especially BirdID, for the convenience of using it on any device without carrying a token. Those who use it less frequently tend to choose A1 for the lower cost.
- Is A1 less secure than A3?
- The A1 is technically more vulnerable because the file can be copied. The A3 is more secure because the cryptographic key never leaves the device (token, card, or cloud). For heavy professional use, A3 is the recommended choice.
Ready to get your certificate?
Chat with us on WhatsApp — we will help you pick the right type and take care of everything.