Python ASN1 Parsing

Python ASN1 Parse

In this post, we will learn how to parse certificate or pem encoded certificate in ASN1 format in python programming language. To parse certificate in ASN1 we will use python module pyasn1.

If you do not have SSL/TSL certificate you can copy certificate form here and save it in cert.pem file.

 # import required module  
 from pyasn1_modules import pem, rfc2459  
 from pyasn1.codec.der import decoder  
 # read pem TLS/SSL certificate  
 substrate = pem.readPemFromFile(open('cert.pem'))  
 # decode certificate in ASN1  
 cert = decoder.decode(substrate, asn1Spec=rfc2459.Certificate())[0]  
 # pretty print ASN1 decoded certificate  
 print(cert.prettyPrint())  

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