fix typo in exception string
fix typo in exception string

imichaelmiers/libforwardsec,imichaelmiers/libforwardsec,imichaelmiers/libforwardsec,ddddavidee/libforwardsec,ddddavidee/libforwardsec,ddddavidee/libforwardsec,imichaelmiers/libforwardsec,ddddavidee/libforwardsec