If you modify a subject of an email by prefixing with a set of characters, does this affect the readability of 1) and email that was sent using a digital certificate? 2) an encrypted email?
Will attempting to modify a message in this manner affect the email for the two specific items above? functionally, would they still be readable. Does any email client/server reject mail because they are intelligent enough to know the message was modified when it was digitally signed?