Convert PEM file to DER

Convert PEM file to DER Python

In this post , we will learn correct way to convert PEM file or PEM SSL certificate into DER using python OpenSSL module.
Below code using python OpenSSL library to load PEM certificate and converting it into DER format. If you do not have PEM SSL certificate, for test purpose you can copy SSL/TLS certificate from here.

 import OpenSSL
  
 # load certificate  
 keyfile = open("/path/to/cert.pem", "r")   
 # read certificate  
 cert_file = keyfile.read()  
 # load certificate buffer   
 cert_pem = OpenSSL.crypto.load_certificate(OpenSSL.crypto.FILETYPE_PEM, cert_file)  
 # dump pem certificate into der  
 cert_der = OpenSSL.crypto.dump_certificate(OpenSSL.crypto.FILETYPE_ASN1,cert_pem)  
 # print der certificate  
 print (cert_der)  

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Rozgardesh (रोजगार देश)