Convert .cer to .p12

What works for me dealing with Push Notification certifies has been:

1. Open the certificate: open my_filename.cer and click "View Certificates" to see the certificate's name
2. Go to Applications -> Utilities -> Keychain Access
3. Ensure you have selected the "login" keychain, not the "system" one (thanks to @Matt Flettcher )
4. Go to "Certificates"
5. Look for the desired certificate
6. Ensure that you can expand it and see under it the original ".certSigningRequest" used to generate the certificate
7. 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

this should prompt to ask a password for this .p12 file.

CF:

aps_developer_identity.cer to p12 without having to export from Key Chain?

Creating a .p12 file

I had the same problem. .p12 Export was not available, only .p7b

I solved it very easily:

You don´t select your certificate via the "certificates" directory on the lower left, but via the "My Certificates" directory.

Like this, an arrow should show up left of your certificate.Click it, and you will see your private Key.

Right-Click on your private Key and select the "export Key" option. Now you can create a .p12 Certificate File, just as the doctor ordered.

Good Luck!