BfArM requires .CER in binary DER X.509 format. Please use the following commands to extract your .cer file:
openssl pkcs12 -in filename.p12 -clcerts -nokeys -out filename.crt
openssl x509 -outform der -in
filename
.crt -out filename.cer
The "filename.cer" needs to be uploaded at PharmNet.Bund.
The "filename.p12" needs to be imported into your web browser.