(VB.NET) Add DomainKey-Signature Header to MIME / Email

Demonstrates how to add a DomainKey-Signature header field to a MIME message.

Note: The DKIM / DomainKey functionality is included with the Chilkat MIME license.

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

Dim dkim As New Chilkat.Dkim

' To create a DomainKey signature for email (i.e. MIME),
' you'll need to provide the following:
' (1) An RSA private key in any common file format.
' (2) The domain name (typically the same domain
' as the sender of an email).
' (3) A selector for the domain name -- an arbitrary string
' to identify the matching public key in DNS.

' To allow an email recipient to verify the DomainKey signature via an
' external email client supporting DomainKey or using other software,
' you will need to create a DNS record with the selector
' and matching public key.  This example does not provide
' information about DomainKey DNS record creation.  
' (Chilkat does not provide an API for creating DNS records.  
' Creating the DomainKey DNS record is something you would do
' manually.)

' Set the domain and selector:
' You'll need to provide your own values here..
dkim.DomainKeyDomain = "chilkatsoft.com"
dkim.DomainKeySelector = "salmon"

' Load a private key from any common RSA private key
' format, such as DER, PKCS8, PEM, XML, etc.
' The LoadDomainKeyPkFile method automatically detects
' the file format and reads it appropriately.
' If a password is not required, you'll still need to provide
' a password string argument, but it is ignored.
Dim password As String
password = "optionalPassword"
Dim success As Boolean = dkim.LoadDomainKeyPkFile("myPrivateKey.pem",password)
If (success <> True) Then
    Debug.WriteLine(dkim.LastErrorText)
    Exit Sub
End If


' Load a MIME file into a byte array.
Dim fac As New Chilkat.FileAccess
Dim mimeData() As Byte
mimeData = fac.ReadEntireFile("testMessage.eml")
If (fac.LastMethodSuccess <> True) Then
    Debug.WriteLine(fac.LastErrorText)
    Exit Sub
End If


' Sign it.  This adds the DomainKey-Signature header and
' returns the new MIME with DomainKey-Signature added.
Dim domainKeySignedMime() As Byte
domainKeySignedMime = dkim.AddDomainKeySignature(mimeData)
If (dkim.LastMethodSuccess <> True) Then
    Debug.WriteLine(dkim.LastErrorText)
    Exit Sub
End If


success = fac.WriteEntireFile("domainKeySigned.eml",domainKeySignedMime)
If (success <> True) Then
    Debug.WriteLine(fac.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Success.")