VB.NET

Email BCC Recipients

See more Email Object Examples

Explains the meaning of BCC recipients, how it is different than CC recipients, and how Chilkat handles BCC. VB.NET

' In the context of email communication, the BCC (Blind Carbon Copy) field is used to send a copy of an email
' to recipients without revealing their addresses to other recipients. When it comes to the MIME
' header of an email, the BCC email addresses should not be included.
' 
' The MIME header is a part of an email message that contains metadata and other information about the email,
' such as the sender, recipient(s), subject, and other details. However, the BCC field is meant to be a confidential field,
' and its purpose is to hide the recipients� email addresses from each other.
' 
' Including BCC email addresses in the MIME header would defeat the purpose of using BCC since it would expose
' the hidden recipients� addresses to the other recipients. This violates the intended privacy and confidentiality of the BCC feature.
' 
' To maintain the confidentiality of BCC recipients, the BCC field should only be used in the envelope of
' the email during the SMTP (Simple Mail Transfer Protocol) transaction. The SMTP server handles the actual
' delivery of the email to the respective recipients while keeping the BCC information hidden from other recipients.
' 
' It is important to ensure that BCC email addresses are not included in the MIME header of an email to
' preserve the privacy and confidentiality of the recipients.

' -----------------------------------------------------------------------------------------
' To discuss how Chilkat handles BCC, let's first create an email with some BCC recipients.
Dim email As New Chilkat.Email

email.AddTo("Joe","joe@example.com")
email.AddTo("Mary","mary@example.com")
email.AddCC("Steve","steve@example.com")
email.AddBcc("Jerry","jerry@example.com")
email.AddBcc("Tom","tom@example.com")

email.Subject = "test"
email.Body = "test"

' Let's examine the MIME
Debug.WriteLine(email.GetMime())
Debug.WriteLine("----------------")

' We have the following.
' Notice the BCC addresses are not present.  They are not included in the MIME header.

' MIME-Version: 1.0
' Date: Mon, 10 Jul 2023 13:57:22 -0500
' Message-ID: <34606FFCB4A440B20E549A223F2F7BF0EB10EE2C@SLICE>
' Content-Type: text/plain; charset=us-ascii; format=flowed
' Content-Transfer-Encoding: 7bit
' X-Priority: 3 (Normal)
' To: Joe <joe@example.com>, Mary <mary@example.com>
' Cc: Steve <steve@example.com>
' Subject: test
' 
' test

' However the BCC address are still stored in the Chilkat email object.
' For example, you can examine the BCC recipients in the email object like this:
Dim numBcc As Integer = email.NumBcc
Debug.WriteLine("Num BCC recipients = " & numBcc)

Dim i As Integer = 0
While i < numBcc
    Debug.WriteLine(i)
    Debug.WriteLine(email.GetBcc(i))
    Debug.WriteLine(email.GetBccName(i))
    Debug.WriteLine(email.GetBccAddr(i))
    Debug.WriteLine("-----")
    i = i + 1
End While

' Output:

' Num BCC recipients = 2
' 0
' Jerry <jerry@example.com>
' Jerry
' jerry@example.com
' -----
' 1
' Tom <tom@example.com>
' Tom
' tom@example.com
' -----


' Thus, when the email is sent, it will also be sent to the BCC recipients,
' but the email received by each of the recipients (i.e. the raw MIME of the email) 
' should not and will not include the BCC email addresses.  There should be no way
' for the recipients to know that the email was sent to the BCC addresses -- because if 
' there is a way to know, then it is not truly BCC.