Archive for September 1st, 2017

Converting .crt .cer .der to PEM, converting .PEM to .DER and convert .PFX PKCS#12 (.P12) to .PEM file using OpenSSL

Friday, September 1st, 2017


These commands allow you to convert 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.

  • Convert a DER file (.crt .cer .der) to PEM


    openssl x509 -inform der -in certificate.cer -out certificate.pem
  • Convert a PEM file to DER


    openssl x509 -outform der -in certificate.pem -out certificate.der
  • Convert a PKCS#12 file (.pfx .p12) containing a private key and certificates to PEM


    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.

  • Convert a PEM certificate file and a private key to PKCS#12 (.pfx .p12)


    openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key \
    -in certificate.crt -certfile CACert.crt

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