Verify DomainKey-Signature Headers in Downloaded Email
See more DKIM / DomainKey Examples
Downloads email from an IMAP server and verifies the DomainKey-Signature header(s) in each email, if present.
Note: DKIM-Signatures are much more common than DomainKey-Signatures. See the other Chilkat example for verifying DKIM-Signatures (link in the code below).
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<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0
' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.
set imap = Server.CreateObject("Chilkat.Imap")
' Connect to an IMAP server, login, select mailbox..
' Use TLS
imap.Ssl = 1
imap.Port = 993
success = imap.Connect("imap.example.com")
If (success = 1) Then
success = imap.Login("myLogin","myPassword")
If (success = 1) Then
success = imap.SelectMailbox("Inbox")
End If
End If
If (success <> 1) Then
Response.Write "<pre>" & Server.HTMLEncode( imap.LastErrorText) & "</pre>"
Response.End
End If
' Note: DKIM-Signatures are much more common than DomainKey-Signature
' See DKIM-Signature Verify Sample.
set dkim = Server.CreateObject("Chilkat.Dkim")
' Download a max of 10 emails and verify any DomainKey-Signature headers
' that are present.
' Download emails by sequence numbers (not UIDs).
bUid = 0
n = imap.NumMessages
If (n > 50) Then
n = 50
End If
set json = Server.CreateObject("Chilkat.JsonObject")
json.EmitCompact = 0
' To verify DomainKey-Signature headers, we need the exact unmodified MIME bytes of each email.
set mimeData = Server.CreateObject("Chilkat.BinData")
seqNum = 1
Do While seqNum <= n
' The FetchSingleBd method was introduced in v9.5.0.76
success = imap.FetchSingleBd(seqNum,bUid,mimeData)
If (success <> 1) Then
Response.Write "<pre>" & Server.HTMLEncode( imap.LastErrorText) & "</pre>"
Response.End
End If
' Note: DKIM-Signatures are much more common than DomainKey-Signature
' See DKIM-Signature Verify Sample.
' Get the number of DomainKey-Signature headers.
numSigs = dkim.NumDomainKeySigs(mimeData)
' Verify each..
j = 0
Do While j < numSigs
Response.Write "<pre>" & Server.HTMLEncode( "------ DomainKey Signature " & j) & "</pre>"
success = dkim.DomainKeyVerify(j,mimeData)
If (success <> 1) Then
Response.Write "<pre>" & Server.HTMLEncode( "Not valid.") & "</pre>"
Response.Write "<pre>" & Server.HTMLEncode( dkim.LastErrorText) & "</pre>"
Else
Response.Write "<pre>" & Server.HTMLEncode( "valid.") & "</pre>"
End If
' Show the additional information about the signature verification
success = json.Load(dkim.VerifyInfo)
Response.Write "<pre>" & Server.HTMLEncode( json.Emit()) & "</pre>"
' 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
Loop
seqNum = seqNum + 1
Loop
success = imap.Disconnect()
%>
</body>
</html>