This property specifies the E-mail address of identity.
As specified by RFC 2459, The format of an rfc822Name is an «addr-spec» as defined in RFC 822. An addr-spec has the form «local-part@domain». Note that an addr-spec has no phrase (such as a common name) before it, has no comment (text surrounded in parentheses) after it, and is not surrounded by "<" and ">". Note that while upper and lower case letters are allowed in an RFC 822 addr-spec, no significance is attached to the case.