Encrypt Outlook Mail Programmatically via VBA

Question

I am looking for a way to encrypt and send Outlook mail via VBA code in Outlook 2013.

I was hoping I could access the mail object and call something like an \"encryp

Answer 1

You will need to set the PR_SECURITY_FLAGS property. See https://blogs.msdn.microsoft.com/dvespa/2009/03/16/how-to-sign-or-encrypt-a-message-programmatically-from-oom/ for an example.

Answer 2

This information is surprisingly hard to find. In case the above link dies, here is a function that implements setting the PR_SECURITY_FLAGS property.

'---------------------------------------------------------------------------------------
' Procedure : Mailitem_SignEncr
' Date      : 2019-06-11
' Author    : Andre 
' Purpose   : Set security flags for an Outlook Mailitem
'
' Source: https://blogs.msdn.microsoft.com/dvespa/2009/03/16/how-to-sign-or-encrypt-a-message-programmatically-from-oom/
' Parameters:
' oItem: If your code runs in Outlook VBA, you can use this to get the current mail: Set oItem = Application.ActiveInspector.CurrentItem
'        Otherwise you get this object when creating the new mail item.
' doSign: Digital Signature. +1 = ON, -1 = OFF, 0 = leave default
' doEncr: Encryption.        +1 = ON, -1 = OFF, 0 = leave default
'---------------------------------------------------------------------------------------
'
Public Sub Mailitem_SignEncr(oItem As Outlook.MailItem, doSign As Long, doEncr As Long)

    Const PR_SECURITY_FLAGS = "http://schemas.microsoft.com/mapi/proptag/0x6E010003"
    Const SECFLAG_ENCRYPTED As Long = &H1
    Const SECFLAG_SIGNED As Long = &H2

    Dim SecFlags As Long

    ' Get current flags value
    SecFlags = oItem.PropertyAccessor.GetProperty(PR_SECURITY_FLAGS)

    ' Turn flags on/off

    If doSign > 0 Then
        ' ON
        SecFlags = SecFlags Or SECFLAG_SIGNED
    ElseIf doSign < 0 Then
        ' OFF
        SecFlags = SecFlags And (Not SECFLAG_SIGNED)
    Else
        ' leave this flag as it is
    End If

    If doEncr > 0 Then
        SecFlags = SecFlags Or SECFLAG_ENCRYPTED
    ElseIf doEncr < 0 Then
        SecFlags = SecFlags And (Not SECFLAG_ENCRYPTED)
    End If

    ' and set the modified flags
    oItem.PropertyAccessor.SetProperty PR_SECURITY_FLAGS, SecFlags

End Sub