VBScript

Get the Certificate Used to Decrypt an Email

Demonstrates the Chilkat Email.LastDecryptCert method, which copies the certificate used to decrypt this email into a Cert object. It should be called after a successful decryption. This example loads an encrypted email and, if it was decrypted, reads the decrypting certificate's common name.

Background: When a message could be decrypted with one of several available private keys, it is often useful to know which certificate actually did the job — for auditing, for confirming the message was encrypted for the expected identity, or for logging. LastDecryptCert hands you that certificate as an object so you can inspect its subject, issuer, validity dates, and more.

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VBScript

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

success = 0

'  Demonstrates the LastDecryptCert method, which copies the certificate used to decrypt
'  this email into a Cert object.  Call it after a successful decryption.

set email = CreateObject("Chilkat.Email")

success = email.LoadEml("qa_data/eml/encrypted.eml")
If (success = 0) Then
    outFile.WriteLine(email.LastErrorText)
    WScript.Quit
End If

If (email.ReceivedEncrypted = 1) Then
    If (email.Decrypted = 1) Then
        '  Get the certificate that was used to decrypt the email.
        set cert = CreateObject("Chilkat.Cert")
        success = email.LastDecryptCert(cert)
        If (success = 1) Then
            outFile.WriteLine("Decrypted with certificate (CN): " & cert.SubjectCN)
        End If

    End If

End If

'  Note: The path "qa_data/..." is a relative local filesystem path,
'  relative to the current working directory of the running application.

outFile.Close