====== Certificates - verifying our network identity ======

In case you need our RADIUS server certificate, or the Certificate Authority certificate, we offer download below.

Local copies are also available below.

**CA certificates:** \\
[[https://pki.cesnet.cz/cs/ch-tcs-crt-crl.html#rsa_certifikaty_-_koren_usertrust_rsa_certification_authority|CESNET – Certificate chain of TCS server certificates]]

**USERTrust RSA Certification Authority** (root CA) \\
SHA1 Fingerprint – 2B:8F:1B:57:33:0D:BB:A2:D0:7A:6C:51:F7:0E:E9:0D:DA:B9:AD:8E  \\
SHA256 Fingerprint – E7:93:C9:B0:2F:D8:AA:13:E2:1C:31:22:8A:CC:B0:81:19:64:3B:74:9C:89:89:64:B1:74:6D:46:C3:D4:CB:D2

<del>
**radius.sin.cvut.cz** – [[https://tcs.cesnet.cz/certificate/download-pem/1695315507|download in PEM format]] \\
SHA1 Fingerprint - 02:B0:6E:34:69:C3:F1:85:53:3A:EB:63:29:F6:69:F5:3B:71:F5:A6 \\
SHA256 Fingerprint - 20:DE:B4:DA:69:AA:0E:45:19:5C:5D:5C:F3:1E:47:B9:97:BD:D5:23:F0:F0:66:C7:CB:1B:45:37:61:CE:9A:44
</del>

**radius.sin.cvut.cz** – [[https://tcs.cesnet.cz/certificate/download-pem/1726768050|download in PEM format]] \\
SHA1 Fingerprint - B2:17:59:F3:41:3D:32:B3:7E:B3:D4:D2:4C:03:5E:8E:D9:D5:FF:F0 \\
SHA256 Fingerprint - 99:7A:FB:28:47:D4:5E:FD:29:7F:60:8B:42:8C:9F:9F:46:AF:0A:72:7B:9C:C0:DD:B3:9C:04:0F:39:99:83:96
===== Local certificate copies (when connecting from registration network) =====

To save these to your device, right-click/tap-and-hold on these links and select **Save link as...** / **Save target as...**

{{ :verejne:sit:usertrust_rsa_certification_authority.crt |USERTrust RSA Certification Authority - download in DER format}} or
{{ :verejne:sit:usertrust_rsa_certification_authority.pem.crt |PEM format}}

(one or the other will work)

===== Install certificates in OS Android =====

First, download these certificates into your Android device. We recommend using Chrome or integrated browser to perform the download, or download them using your laptop/computer and transfer to your Android using a USB cable or an SD card.

{{ :verejne:sit:usertrust_rsa_certification_authority.pem.crt |USERTrust RSA Certification Authority - download in PEM format}}

The following instructions differ from device to device, but they all follow the same theme:

In your Android device:

  * Go to **Settings** -> **Wi-Fi**.
  * Go to **Advanced Wi-Fi**. This can be hidden in a context menu.
  * Choose **Install a certificate**.
    * A file browser should open. Find your downloaded certificate file (usually in "Downloads" directory) and tap the file. (You only need to install one of the PEM/DER. If one fails, try the other one.)
    * Follow the instructions on your device. Choose a name for the certificate, like "UserTrust CA" or "Sincoolka".
    * Choose Wi-Fi as a certificate type, if possible.
    * Confirm the installation.
  * Then, [[en:verejne:sit:wi-fi:android|during setting up Wi-Fi]], select this new certificate as a **CA certificate**.

<note important>
When you remove the Sincoolka Wi-Fi settings, the saved certificate might also get removed. Therefore, you might need to repeat the procedure above.
</note>