VB.NET

S/MIME Encrypt .eml without Sending

See more Email Object Examples

Demonstrates how to encrypt an email using the recipient's digital certificate. This example just encrypts, and does not send the email. VB.NET

Dim success As Boolean = False

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

Dim email As New Chilkat.Email

success = email.LoadEml("c:/temp/email/unencrypted.eml")
If (success = False) Then
    Debug.WriteLine(email.LastErrorText)
    Exit Sub
End If


' The email content is encrypted using AES with a 256-bit key, operating in GCM mode, which provides authenticated encryption.
email.Pkcs7CryptAlg = "aes-gcm"
email.Pkcs7KeyLength = 256
email.OaepPadding = True
email.OaepHash = "sha256"
email.OaepMgfHash = "sha256"

Dim cert As New Chilkat.Cert
success = cert.LoadFromFile("c/temps/cert/recipient.cer")
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


email.SendEncrypted = True
email.SetEncryptCert(cert)

Dim sbSmime As New Chilkat.StringBuilder

' The mailman object applies the encryption by rendering the email according to the instructions (property settings) provided in the email object.
' No email is sent.
Dim mailman As New Chilkat.MailMan
success = mailman.RenderToMimeSb(email,sbSmime)
If (success = False) Then
    Debug.WriteLine(mailman.LastErrorText)
    Exit Sub
End If


success = sbSmime.WriteFile("c:/temp/encryptedEmail.eml","utf-8",False)
If (success = False) Then
    Debug.WriteLine(mailman.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Success!")