The signature can be checked as follows:
1. With software
Install intarsys' free Sign Live! CC validation client. The software will compare the certificate that I2PS uses to sign a file with the blacklists provided by trust centers, enabling you to determine whether the signature is valid and really comes from the sender.
If you are unable to install signature validation software, you can use AuthentiDate instead to check that the signature and certificate match. AuthentiDate International is a vendor that is accredited by the German Federal Network Agency and runs a trust center in compliance with the strict requirements of Germany's Digital Signature Act.
Simply upload the test report file you have (you do not need to upload a signature file, as the signature is already integrated into the file). Please make sure to use the Java applet for files bigger than 10 MB.
These two methods will return a check log that complies with the German Digital Signature Act and that confirms the authenticity of I2PS' signature and the fact that the document has not been tampered with.