CER and P12 are both types of digital security certificates created with the OpenSSL program. P12 is a type of encryption within the more well-known PFX family (it shares the extension). To convert a CER certificate to a P12, simply run one command in OpenSSL. The security data will be the same, retaining your access key embedded within the file itself.
Step 1
Open OpenSSL.
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Step 2
Copy and paste the following into the command window: openssl pkcs12 -export -out OUTPUTNAME.pfx -inkey KEY.key -in FILENAME.cer -certfile CACert.crt
Step 3
Replace "OUTPUTNAME" with the desired name of your P12 PFX file.
Step 4
Replace KEY with the access key of the CER (which will be transferred to the P12).
Step 5
Replace "FILENAME" with the name of the existing CER file.
Step 6
Hit Enter. This will perform the conversion, saving the P12 in the same folder as the CER.
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