(Chilkat2-Python) Get Certificate Distinguished Name in .NET Format

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Certificate distinguished names (DN's), in the real world, can be constructed in various ways. Some systems expect certain ways of doing things. This example demonstrates how to get a DN (or SimpleName) exactly as .NET would return it.

This example requires Chilkat v9.5.0.96.

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import sys
import chilkat2

cert = chilkat2.Cert()

success = cert.LoadFromFile("qa_data/certs/testCert.cer")
if (success == False):
    print(cert.LastErrorText)
    sys.exit()

# In 99% of all cases, Chilkat already returns the Distinguished Name in the identical format as .NET.
# 
# In most cases, (internal to the certificate) the ASN.1 for the certificate's Subject 
# contains a sesquence of OIDs and values, where each OID is the single item in a SET.
# For example:

# SEQUENCE (3 elem)
#       SET (1 elem)
#         SEQUENCE (2 elem)
#           OBJECT IDENTIFIER 2.5.4.6 countryName (X.520 DN component)
#           PrintableString FR
#       SET (1 elem)
#         SEQUENCE (2 elem)
#           OBJECT IDENTIFIER 2.5.4.12 title (X.520 DN component)
#           UTF8String Mdecin
#       SET (3 elem)
#         SEQUENCE (2 elem)
#           OBJECT IDENTIFIER 2.5.4.42 givenName (X.520 DN component)
#           UTF8String ALAIN
#       SET (3 elem)
#         SEQUENCE (2 elem)
#           OBJECT IDENTIFIER 2.5.4.4 surname (X.520 DN component)
#           UTF8String DUBOIS RPPS
#       SET (3 elem)
#         SEQUENCE (2 elem)
#           OBJECT IDENTIFIER 2.5.4.3 commonName (X.520 DN component)
#           UTF8String 389900098933

# If we look at the DN, we get this:
subjectDN = cert.SubjectDN
print(subjectDN)

# Chilkat produces this:
# C=FR, Title=Mdecin, G=ALAIN, SN=DUBOIS RPPS, CN=389900098933

# However, if the certificate's internal ASN.1 groups several items in a single SET,
# such as shown below, Microsoft .NET will produce a DN like this:
# G=ALAIN + SN=DUBOIS RPPS + CN=389900098933, T=Mdecin, C=FR

# Notice how the items in the SET are grouped with " + ".
# Also notice the order is reverse, and "T" is used instead of using "Title.
# These are all variations of how a DN might be formatted.
# In practice, there is no correct way because what is needed depends on what is
# required as input to whatever is receiving the DN.

# SEQUENCE (3 elem)
#       SET (1 elem)
#         SEQUENCE (2 elem)
#           OBJECT IDENTIFIER 2.5.4.6 countryName (X.520 DN component)
#           PrintableString FR
#       SET (1 elem)
#         SEQUENCE (2 elem)
#           OBJECT IDENTIFIER 2.5.4.12 title (X.520 DN component)
#           UTF8String Mdecin
#       SET (3 elem)
#         SEQUENCE (2 elem)
#           OBJECT IDENTIFIER 2.5.4.42 givenName (X.520 DN component)
#           UTF8String ALAIN
#         SEQUENCE (2 elem)
#           OBJECT IDENTIFIER 2.5.4.4 surname (X.520 DN component)
#           UTF8String DUBOIS RPPS
#         SEQUENCE (2 elem)
#           OBJECT IDENTIFIER 2.5.4.3 commonName (X.520 DN component)
#           UTF8String 389900098933

# To ensure Chilkat produces the same DN format as .NET, you can specify
# the keyword "DotNetSimpleName" in the UncommonOptions.
# For example:

cert.UncommonOptions = "DotNetSimpleName"

# If the above option is used (which was added in Chilkat v9.5.0.96), then Chilkat
# will produce the DN in the same format as .NET

subjectDN = cert.SubjectDN
print(subjectDN)

# Now Chilkat produces this:
# G=ALAIN + SN=DUBOIS RPPS + CN=389900098933, T=Mdecin, C=FR