$C_i$	Client entity
$CS$, $AS$, $DS$	Central server, Attributes server and Data server
$MS$	Master secret/Master signature
$SS$	One secret sharing
$S_{ID}$, $O_{ID}$	Subject ID, Object ID
$S_R$, $O_R$	Subject role, Object role
$U{R}_i$	User’s role (patient, patient relative or provider)
$C{N}_i$	Client’s number
$R{N}_i$	Role’s number
$U{N}_i$	User’s number
$SP$, $OP$	Subject ’s pseudonym and Object ’s pseudonym
$S_{sp}$, $S_{op}$	Signature of $SP$ and Signature of $OP$
$R{N}_{sp}$, $U{N}_{sp}$	$R{N}_i$, $U{N}_i$ for $SP$
$R{N}_{op}$, $U{N}_{op}$	$R{N}_i$, $U{N}_i$ for $OP$
N, $SN$	Random nonces and random secret nonce
$TS$	Timestamp
$C_i{S}_j$	Signature generated by $C_i$ and j is signature number
$CS{S}_j$	Signature generated by $CS$
$AS{S}_j$	Signature generated by $AS$
$DS{S}_j$	Signature generated by $DS$
||, ⊕, $tm$	Concatenation operation, Exclusive or operation and Temporary