(CkPython) IMAP Download and Verify Signed MIME

Downloads the original MIME of a digitally signed email and saves the .p7s signature along with other MIME parts. It then imports the email into a Chilkat email object to unwrap the S/MIME and verify the signature, and subsequently saves the attachments if they haven't been saved already.

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat Python Downloads install with pip pip3 install chilkat or download... Python Module for Windows, MacOS, Linux, Alpine Linux

import sys
import chilkat

success = False

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

imap = chilkat.CkImap()

# Connect to an IMAP server.
# Use TLS
imap.put_Ssl(True)
imap.put_Port(993)
success = imap.Connect("imap.example.com")
if (success == False):
    print(imap.lastErrorText())
    sys.exit()

success = imap.Login("myLogin","myPassword")
if (success == False):
    print(imap.lastErrorText())
    sys.exit()

# Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
if (success == False):
    print(imap.lastErrorText())
    sys.exit()

# Download the 1st email (as MIME) in the Inbox by sequence number.
sbMime = chilkat.CkStringBuilder()
success = imap.FetchSingleAsMimeSb(1,False,sbMime)
if (success == False):
    print(imap.lastErrorText())
    sys.exit()

# Load it into a MIME object and check to see if it is signed
mime = chilkat.CkMime()
mime.LoadMimeSb(sbMime)
alreadySavedParts = False
if (mime.ContainsSignedParts() == True):

    # This will save the .p7s and other parts...
    st = chilkat.CkStringTable()
    success = mime.PartsToFiles("c:/temp/qa_output",st)
    if (success == True):
        numFiles = st.get_Count()
        i = 0
        while i < numFiles :
            print("Created: " + st.stringAt(i))
            i = i + 1

        alreadySavedParts = True

# Load the MIME into an Email object.  This unwraps the security layers and verifies signatures.
email = chilkat.CkEmail()
email.SetFromMimeSb(sbMime)

if (email.get_ReceivedSigned() == True):

    print("This email was signed.")

    # Check to see if the signatures were verified.
    if (email.get_SignaturesValid() == True):
        print("Digital signature(s) verified.")

        print("Signer: " + email.signedBy())

        # The certificate used for signing may be obtained
        # by calling email.GetSignedByCert.
        cert = chilkat.CkCert()
        success = email.LastSignerCert(i,cert)
        if (success == False):
            print("Failed to get signing certificate object.")
        else:
            print("Signing cert: " + cert.subjectCN())

else:
    print("Digital signature verification failed.")

if (alreadySavedParts != True):
    email.SaveAllAttachments("c:/temp/qa_output")