Convert .cer To .p12
Answer : What works for me dealing with Push Notification certifies has been: Open the certificate: open my_filename.cer and click "View Certificates" to see the certificate's name Go to Applications -> Utilities -> Keychain Access Ensure you have selected the "login" keychain, not the "system" one (thanks to @Matt Flettcher ) Go to "Certificates" Look for the desired certificate Ensure that you can expand it and see under it the original ".certSigningRequest" used to generate the certificate At this moment you should be able to export it as ".p12" try this: given you have files as follow: aps.cer, downloaded from Apple. app.key, your own private key generated by openssl. 1st, convert the .cer file into .pem format: openssl x509 -in aps.cer -inform DER -out aps.pem -outform PEM 2nd, use the .pem file and your private .key to generate .p12 file: openssl pkcs12 -export -out aps.p12 -inkey app.key -in aps.pem ...