The attSentFor attribute is encoded as counted strings laid end-to-end. The format for attSentFor is as follows:
Unlike other length values, the display-name-length and address-length are unsigned 16-bit values instead of unsigned long integers. They still include terminating null characters, however. The type and address strings in the email-address entry are separated by a literal colon (:) character, such as "smtp:joe@nowhere.com". Only the combined type:address string is null-terminated.