Overview #Often it is necessary to convert a Certificate from one Certificate File Formats to another often for placing the Certificate in one for the Certificate Keystores.
Converting Certificate Formats is often part of a Data Extraction Transformation process.certificates and keys to different formats to make them compatible with specific types of servers or software. For example, you can convert a normal PEM file that would work with Apache to a PFX (PKCS#12) file and use it with Tomcat or IIS.
You can use some of the online SSL Converters to convert certificates without messing with OpenSSL.
openssl x509 -inform der -in certificate.cer -out certificate.pem
openssl x509 -outform der -in certificate.pem -out certificate.der
openssl pkcs12 -in keyStore.pfx -out keyStore.pem -nodes
You can add -nocerts to only output the private key or add -nokeys to only output the certificates.
openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key -in certificate.crt -certfile CACert.crt