Chilkat2-Python

Add a Detached Signature (Separate Key, Header Control)

Demonstrates the Chilkat Mime.AddDetachedSignaturePk2 method, which creates a detached signature with a separately supplied certificate and private key, and a third argument controlling transfer of the existing message header fields to the new outer entity.

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 combines the two variations — certificate and key supplied separately, plus explicit header placement — for the case that needs both. It is the most flexible of the detached-signature methods; choose it when your key material is separate and you also care about where the message headers end up on the signed result.

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import sys
import chilkat2

success = False

mime = chilkat2.Mime()
success = mime.SetBodyFromPlainText("This message will be signed.")
if (success == False):
    print(mime.LastErrorText)
    sys.exit()

# Load the certificate and its private key separately.
cert = chilkat2.Cert()
success = cert.LoadFromFile("qa_data/signer.cer")
if (success == False):
    print(cert.LastErrorText)
    sys.exit()

privKey = chilkat2.PrivateKey()
success = privKey.LoadPemFile("qa_data/signer_privkey.pem")
if (success == False):
    print(privKey.LastErrorText)
    sys.exit()

# Create a detached signature with separately supplied cert and private key, where the 3rd
# argument controls whether the existing message header fields are transferred to the new outer
# multipart/signed entity.
transferHeaderFields = True
success = mime.AddDetachedSignaturePk2(cert,privKey,transferHeaderFields)
if (success == False):
    print(mime.LastErrorText)
    sys.exit()

success = mime.SaveMime("qa_output/signed.eml")
if (success == False):
    print(mime.LastErrorText)
    sys.exit()

print("Detached signature added (headers transferred).")