Key Agreement Phase. In the key agreement phase, the actual symmetric secret shared SK between SM and SP is established. We denote the SM by the entity with identity XXX, key pair (dA, PA) and certificate certA. Similar, the SP is denoted by the entity with identity IDB, key pair (dB, PB) and certificate certB. The detailed description is as follows. SP broadcast: Every fixed period, the SP broadcasts the EC point M0 = {R2}. This point is computed by randomly choosing a variable r2 and R2 = r2P.
Key Agreement Phase. Xxxxx and Xxx each chooses random values a, b ∈ Z∗. Given these initializations, the protocol is as follows: Protocol messages: A −→ B: TA=aP B −→ A: TB=bP . After the above messages are exchanged, Xxxxx com- putes KAB = e(QB, PB)a · e(xASA, TB), and Xxx computes KBA as follows: h(ID). (For example, Xxxxx’s partial private key from TA is SA = sQA, where QA = h(XXX)); KBA = e(QA , PA )b · e(xBSB , TA).
Key Agreement Phase. In this phase, entities A and B that have private/public key pairs, ( X A = DA , xA , YA = XXX , PA ) and ( X B = DB , xB , YB = IDB , PB ) respectively, execute protocol 1. Description of the protocol is as follows: • Entity A, as initiator of the protocol, chooses two random numbers, rA1, rA2 ∈R Ζ* , and computes n TA1 = rA1P and TA2 = rA2 P such that k A1, k A2 ≠ 0 modn , where k A1 and k A2 are x-coordinates of points TA1 and TA2 respectively. Then A signs points TA1 and TA2 as follows: SA = (k A1 ⋅ k A2 )(xAk AQA + DA )+ (k A1rA1 + k A2rA2 )QA Where k A is x-coordinate of public key PA . At the end of the step, A sends quantities n (TA1,TA2 , SA ,YA = XXX , PA ) to B. • Entity B also, same to A, chooses kB1, kB2 ≠ 0 modn . Then he computes rB1, rB2 ∈R Ζ* and computes TB1 = rB1P and TB2 = rB2 P where, SB = (kB1 ⋅ kB2 )(xBkBQB + DB )+ (kB1rB1 + kB2rB2 )QB Where k B is x-coordinate of public key
Key Agreement Phase. In the key agreement phase, two rounds are required for generating a common conference key for multiple partici- pants, and the way of message exchanges is with respect to the group data sharing model established by the structure E of the (v, k + 1, 1)-design. ∈ ∈
Key Agreement Phase. In the key agreement phase, the sensor node and the CS chooses an elliptic curve EP(a, b), y2 = x3 + ax + b mod P, where P is a generator point on EP(a, b). The key agreement phase generates a shared key between a sensor node (SN) and the CS. The entire key agreement process is illustrated in Figure 2. Sensor Node (SN) Central Server (CS) QSN = h(tokenSN || IDSN || STAMPp1 ) HDP1 = h(QSN || tokenSN || IDSN || STAMPp1 ) (IDSN , STAMPp1, QSN , HDp1 ) Step 1 Checks HD p1 , STAMPp1 QSN1 = h(tokenSN || IDSN || STAMPp1 ) QSN = ?QSN1 Step 2 Checks HD p 2 , STAMPp 2 Generates (F, f ), (R, r) Chooses a1 c (0, m1 ) HDp 2 = h(F || tokenSN || R || STAMPp 2 ) (F, R, a1, STAMPp 2 , HDp 2 ) Generates (E, e) Chooses a2 c (0, m2 ) HDp3 = h(QSN || tokenSN || IDSN || STAMPp3 ) (E, a2 , STAMPp3 , HDp3 ) Step 3 Checks HD p3 , STAMPp3 Computes shared key Computes shared key y = hash(HDp1 || HDp 2 || HDp3 ) M = m * m , M = M / m , y = M –1(mod m )(1 S i S 2) y = hash(HDp1 || HDp 2 || HDp3 ) x ÷ a1 y1M1 + a2 y2M 2 (mod M ) SKSN = e(Fx + yR) x ÷ a1 y1M1 + a2 y2M 2 (mod M ) SKCS = E( fx + yr) Figure 2. The key agreement protocol between the sensor node and the central server.
Key Agreement Phase. In this phase, FA and HA can be authenticated, and a secure session key between MN and FA can be established. The steps of this phase are shown as follows. || || ||
Key Agreement Phase. 3.2.1 Negotiatory Keys (NKs) After deployment, each node needs to find whether it shares any key with its neighbors. To do this, each node generally generates m non-linear equations with the secret keys it carries as expression ⑴ and broadcasts the message containing the encrypted coefficients of
Key Agreement Phase. This phase occurs between the vehicles and without an intervention of a third- party server. This phase is demonstrated in Fig. 2.
Key Agreement Phase. This phase occurs between the vehicles 𝑉𝑖 and Xx without an intervention of a third- party server. This phase is demonstrated in Fig. 2. 𝑝 𝑖
