Certificates for corrected submissions are available for download (for example, in the submission correction page, or in Profile/Programs). These certificates are signed tgz files containing the corrected submissions and information about the user who made them.
In order to check the certificate signature, the Jutge public key has to be downloaded and installed:
To install the public key, run the following command:
gpg --import --armor < jutge_publickey.asc
Then, to check the certificate signature, run the following command:
gpg certificate.tgz.gpg
The signature will be verified, and a certificate.tgz file will be created.