CkPython

Export a Public Key as DER into a BinData

Demonstrates the Chilkat PublicKey.GetDerBd method, which writes the public key as binary DER into a BinData. The first argument selects the representation (as for GetPem) and the second is the BinData that receives the bytes (its contents are replaced).

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: The in-memory binary export: the raw DER lands in a BinData ready to hash, transmit, or hand to another API without a temporary file. It is the BinData counterpart to the text exporters, and the first argument picks the same PKCS #1 versus SubjectPublicKeyInfo structure.

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import sys
import chilkat

success = False

#  Load a public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
#  JWK, and other supported representations.
pubKey = chilkat.CkPublicKey()
success = pubKey.LoadFromFile("qa_data/public.pem")
if (success == False):
    print(pubKey.lastErrorText())
    sys.exit()

#  Write the public key as binary DER into a BinData.  The 1st argument selects the representation
#  (as for GetPem) and the 2nd is the BinData that receives the bytes (its contents are replaced).
preferPkcs1 = False
bd = chilkat.CkBinData()
success = pubKey.GetDerBd(preferPkcs1,bd)
if (success == False):
    print(pubKey.lastErrorText())
    sys.exit()

print("Exported " + str(bd.get_NumBytes()) + " DER bytes.")