. 2020 May 21;20(10):2913. doi: 10.3390/s20102913

Table 1.

Notations.

Notations	Meanings
$P_{i}$	i-th patient
$M C_{j}$	j-th medical center
$N A$	Network Administrator
$I D_{i}, I D_{j}$	Identity of $P_{i}$ and $M C_{j}$
$P W_{i}$	Password of $P_{i}$
$r_{i}, r_{j}$	Secret keys of $P_{i}$ and $M C_{j}$
$s_{N A}$	Secret key of $N A$
$T_{1}, T_{2}$	Timestamps
$T_{u p}, T_{a c c e s s}$	Uploading/accessing time of EHR
$K_{N A}, r_{N A}$	Random numbers generated by $N A$
$P K_{i}, P K_{j}$	Public keys of $P_{i}$ and $M C_{j}$
$C e r t_{i}, C e r t_{j}$	Certificates of $P_{i}$ and $M C_{j}$
$E_{p} (a, b)$	A nonsingular elliptic curve $y^{2} = x^{3} + a x + b$ (mod p)
G	A base point for elliptic curve
$H I D_{i}, P I D_{j}$	Pseudo-identities of $P_{i}$ and $M C_{j}$
$T_{x}$	Log transaction
$K M S_{j}$	Secure pre-shared key among $M C_{j}$ and $C S$
$E H R$	Electronic health record
$R I$	Information of health record
$R E$	Request message of EHR
$S K$	Common session key shared among $P_{i}$ and $M C_{j}$
$h (*)$	Collision resistant one-way hash function
⊕	XOR operation
$\| \|$	Concatenation operation