Chilkat2-Python

Verify DKIM-Signature Headers in Downloaded Email

See more DKIM / DomainKey Examples

Downloads email from an IMAP server and verifies the DKIM-Signature header(s) in each email, if present. Chilkat2-Python

import sys
import chilkat2

success = False

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

imap = chilkat2.Imap()

# Connect to an IMAP server, login, select mailbox..
# Use TLS 
imap.Ssl = True
imap.Port = 993
success = imap.Connect("imap.example.com")
if (success == True):
    success = imap.Login("myLogin","myPassword")
    if (success == True):
        success = imap.SelectMailbox("Inbox")

if (success != True):
    print(imap.LastErrorText)
    sys.exit()

dkim = chilkat2.Dkim()

# Download a max of 10 emails and verify any DKIM-Signature headers
# that are present.

# Download emails by sequence numbers (not UIDs).
bUid = False

n = imap.NumMessages
if (n > 10):
    n = 10

json = chilkat2.JsonObject()
json.EmitCompact = False

# To verify DKIM-Signature headers, we need the exact unmodified MIME bytes of each email.
mimeData = chilkat2.BinData()
seqNum = 1
while seqNum <= n :
    # The FetchSingleBd method was introduced in v9.5.0.76
    success = imap.FetchSingleBd(seqNum,bUid,mimeData)
    if (success != True):
        print(imap.LastErrorText)
        sys.exit()

    # Get the number of DKIM-Signature headers.
    numDkim = dkim.NumDkimSigs(mimeData)

    # Verify each..
    j = 0
    while j < numDkim :
        print("------ DKIM Signature " + str(j))

        success = dkim.DkimVerify(j,mimeData)
        if (success != True):
            print("Not valid.")
        else:
            print("valid.")

        # Show the additional information about the signature verification
        json.Load(dkim.VerifyInfo)
        print(json.Emit())

        # The JSON contains information such as this:

        # 	{
        # 	  "domain": "amazonses.com",
        # 	  "selector": "7v7vs6w47njt4pimodk5mmttbegzsi6n",
        # 	  "publicKey": "MIGfMA0GCSqG...v2GvWPqGHz6uqeQIDAQAB",
        # 	  "canonicalization": "relaxed/simple",
        # 	  "algorithm": "rsa-sha256",
        # 	  "signedHeaders": "Subject:From:To:Date:Mime-Version:Content-Type:References:Message-Id:Feedback-ID",
        # 	  "verified": "yes"
        # 	}

        j = j + 1

    seqNum = seqNum + 1

success = imap.Disconnect()