How to convert an SSL certificate in linux

Question

Is there a way how to convert certificates between cer/pem/crt/der/pfx/p12 in Linux? I have an SSL certificate in a .cer file and I need it to be .pem in order to use it.

How can I convert it?

Answer 1

Converting certificates between cer/pem/crt/der/pfx/p12 can be done in Linux with the use of OpenSSL tool via the terminal.

These commands allow you to convert certificates and keys to different formats to make them compatible with specific types of servers or software.

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

For more information see:

http://www.sslshopper.com/article-most-common-openssl-commands.html

https://support.ssl.com/index.php?/Knowledgebase/Article/View/19

Answer 2

Convert .crt to .p12

openssl pkcs12 -export -out server.p12 -inkey server.key -in server.crt

Where server.key , is the server key . server.crt is cert file from CA or self sigh

Answer 3

How to simply generate .cer file for your ionic app ?

We can easily export .cer file of a https url by using google chrome browser. Just click on the padlock icon and export the key file as a base64 based .cer file

Reference

http://uncaughterror.com/programming/ionic3/how-to-integrate-ssl-in-ionic-3-using-cordova-plugin/

https://www.youtube.com/watch?v=6nLK9wJPNRE

Doing the same using a linux machine

openssl s_client -showcerts -connect <domain name>:443 -servername <domain name>:443 </dev/null | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > certificate.pem

Convert .pem file into .cer file

openssl x509 -inform PEM -in certificate.pem -outform DER -out certificate.cer