Why would I send a Clear Text version with a signed and encrypted message? Doesn that defeat the whole point of encryption?
When an email is digitally signed, the whole email and signature are packaged into a smime.p7m attachment.(i.e. just the ‘Attachment’ area in the diagram below is sent. The message and the digital signature are contained within the.p7m). S/MIME clients like Outlook read this attachment and display the email and signature. Non-S/MIME clients like IncrediMail won’t understand what the .p7m attachment is and will show a blank mail with just the.p7m attachment. With ‘Send Clear text…’ enabled, the signature and the message body are split up (as in the diagram). S/MIME clients will use the signature to verify the authenticity and integrity of the message whilst non- S/MIME clients will at least be able to display a plaintext version of the mail. Sending a ‘clear text’ version of a digitally signed message does not compromise the security of an encrypted mail. This is because the encryption part of the equation is carried out on the message after it has been signed. This means the entire s
