BCC Email Addresses Should Never be in “BCC” MIME Headers

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 (Multipurpose Internet Mail Extensions) 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.