CkPython

Export a Private Key as DER into a BinData

Demonstrates the Chilkat PrivateKey.GetPkcsBd method, which exports the key as DER into a BinData. The first argument selects PKCS #1 (true) versus PKCS #8 (false), the second is the password (empty for unencrypted), and the third is the BinData that receives the bytes.

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: This is the in-memory binary export — the raw DER bytes land in a BinData ready to hash, encrypt, or hand to another API without a temporary file. One method covers several cases: the boolean picks the traditional (PKCS #1) versus modern (PKCS #8) structure, and a nonempty password produces an encrypted PKCS #8 export (with the cipher from Pkcs8EncryptAlg). Source any password securely.

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import sys
import chilkat

success = False

#  Load a private key to export.
privKey = chilkat.CkPrivateKey()
success = privKey.LoadPemFile("qa_data/private.pem")
if (success == False):
    print(privKey.lastErrorText())
    sys.exit()

#  The key password is not hard-coded in a real application; obtain it from an interactive
#  prompt, environment variable, or a secrets vault.
password = "myKeyPassword"

#  Export the key as DER into a BinData.  The 1st argument selects PKCS #1 (True) versus PKCS #8
#  (False); the 2nd is the password (empty string for an unencrypted export); the 3rd is the
#  BinData that receives the DER bytes.
usePkcs1 = False
bd = chilkat.CkBinData()
success = privKey.GetPkcsBd(usePkcs1,password,bd)
if (success == False):
    print(privKey.lastErrorText())
    sys.exit()

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