S/MIME with multiple e-mail address certificates: A usability study

Multiple e-mail address certificates have been proposed very recently, therefore, neither certification authorities currently issue such a certificate nor does any mail client permit its use for signing or encrypting e-mail messages. Further, no study has been made to evaluate their effectiveness for practical use. This paper studies the usability of multiple e-mail address certificates in secure messaging. It discusses S/MIME, its usefulness in e-mail security, current adoption by users, advantages, and disadvantages. It illustrates procedures in vogue for singing, encrypting, and both signing and encrypting e-mail messages using e-mail address certificates. It further reports the results of study carried out to evaluate user efficiency in sending/receiving S/MIME mail with and without the use of multiple e-mail address certificates.