Proposed Protocol. TP-AMP TP-AMP stands for the Three-Pass Authenticated key agreement via Memorable Passwords and is depicted in Figure 1. Let us borrow the name AMP from [21] for our basic motivation.
Proposed Protocol. Step 1: Preparing user contribution and signa- ture Each user Ui with identity IDi chooses its con- tribution (xi) randomly. Let Ci be the current value of counter for user Xx. The values of (IDi||ID0||xi||Ci) are then encrypted with U0’s public key. Here || denotes the concatenation op- eration. ei = {IDi||ID0||xi||Ci}pu0 Ui also takes a signature sigi of (IDi||ID0||xi||Ci) using it’s private signature key. sigi = τ pri (IDi||ID0||xi||Ci) Each user then sends ei, sigi to the U0. Ui → U0 : ei, sigi All these operations can be performed offline. The advantage of using counter over timestamp is that the operations involving the counter can be per- formed offline. • Step 2: Receipt of user message and verification at U0 The U0 receives all the messages and decrypts them. It then verifies all the signatures of the cor- responding users. It also checks the validity of the counter Ci and accepts if the signatures are valid. • Step 3: Computation of secret by U0 The pair of identity and random value (IDi, xi) re- ceived from each user is taken as it’s contribution to construct the key. U0 also selects a random number x0 ∈ G p as its contribution. The secret is constructed by interpolating all the contributions into a polynomial. The n + 1 values of (IDi, xi) are taken as (n + 1) input points to the interpola- tion algorithm. As, all the identities of the users are distinct, a distinct polynomial will be obtained from the fresh input. Let the coefficients of the resulting polynomial be a0, a1, . . . , an. Thus the polynomial is as follows: A(x) = a0 + a1x + a2x2 + . . . + anxn The secret value is constructed as K = (a0||a1|| . . . ||an). • Step 4:Computation of reply message from U0 For each user Ui, U0 computes a one way hash H (IDi, ID0, xi,Ci) over the identity IDi, ID0, counter Ci and contribution xi. Then the secret value K is bitwise XORed with this hash value to
Proposed Protocol. In the distributed group key agreement protocol, each group member is equal, which means that before the group key is negotiated, each group member usually needs to consume many communication and computing resources to perform mutual authentication with all other group members. In order to reduce these costs, in our protocol, we arrange all GNs into a list according to their identities. According to the list, before the group key is negotiated, each GN only needs to send an authentication request to its right neighbor once and be authenticated by its right neighbor. In other words, each GN will receive an authentication request from its left neighbor and authenticate its left neighbor. Since each GN only needs to complete authentication once, this can greatly reduce the computation and communication costs caused by authentication between group members. In addition, when any GN needs to join or leave the group, only the left neighbor of the GN needs to update the parameters, which can also reduce the computation and communication overhead. Our protocol has seven parts: the initialization phase, the registration phase, the mutual authentication phase, the group key generation phase, the GN join phase, the GN leave phase, and the internal attacker detection process. When the system runs for the first time, the initialization phase is performed by the System Administrator (SA). Each GN performs the registration phase before entering the network. When the group key needs to be negotiated, all GNs perform the mutual authentication phase and the group key generation phase. When a GN wants to join a group, it needs to perform the GN join phase. When a GN in the group wants to leave, the GN leave phase is performed. If the group key fails to be generated multiple times, the KDC will execute the internal attacker detection process to find the malicious GN and expel it from the group. Suppose there are GNi(1 ≤ i ≤ n) that need to generate the group key, and their identities are IDi(1 ≤ i ≤ n), where n is the number of GN. Since there may be multiple groups, we named each group GIDu, where u is the number of groups. Each group has a list L that stores the identity IDi of all GNs in the group and is managed by the KDC. All IDi in L are sorted in descending order, and L is a circular list, which means that the largest IDi and the smallest IDi are linked. Table 1 shows the description of the symbols. The details of the above seven parts are as follows.
Proposed Protocol. The proposed protocol chooses a k-bit prime p and determine following public parameters: {Fp, E/Fp, G, P}. where E/Fp: Elliptic curve over Fp. G: Cyclic additive points group formed by points on E/Fp. P: Generator of G. The protocol describes operation to generate common Session key among n members (it is not important whether n is equal to 3k or not) called Initialization operation along with others group operations like Join, Leave, Merge, etc. for dynamic group.
Proposed Protocol. Consistent with the pilot projects that have been deployed in Canada, we propose the following protocol: Type of ash tree configurations: 1-Parks or street alignment. More than 30 trees would be required in a park to show appropriate results. The ash trees will have to have a DBH of at least 8 inches. Street alignment would also require more than 30 ash trees with similar characteristics of trees described in the park scenario. Every ash tree in the sample will be georeferenced and different physical condition data collected. Any available information on EAB trapping results or branch sampling will be helpful in selecting potential trial sites and designing the control device network. The final selection of trees for the test(s) will have to be done on site in collaboration with the relevant operation managers (town, university or state as relevant).
Proposed Protocol. This section describes that initially how n numbers of members agreed up on a common session key under ini- tialization operation followed by the the join and leave procedures. Assumptions: The following assumptions has been considered in proposed protocol. Firstly, let of Algorithm 2 started from Ki+1 which is equivalent to the following calculations: { · · · } R U = U1, U2, , Un be the set of mobile nodes. Secondly, each group at beginning must know the identity of Ki+1 R = X i+1 ⊕ Ki others group members by some sort of other mechanism. Thirdly the protocol assumes a trusted server which is responsible for private key generation for the users, called key generation centre (KGC) in the system. The subscript notation for the participants are must be considers in logical ring fashion e.g. Un+1 = U1 and U0 = Un in entire paper.
Proposed Protocol. The basic architecture of proposed DRM system is similar to Xxx et al. [10] system. Here, the content provider handles the content packing (encryption) work. Once the content encryption is over, it provides the content key with usage rules to the license server and protected content with content information to the distributor. License server authenticates the user, receives the payment, and generates the license. While, Distributor works as a service provider and facilitates the protected content distribution in the system. Parties involved in our DRM model are: – Private key generator (PKG) – Content provider (C) – Distributor (D) – License server (L) – DRM User (U ) Content provider keeps the original unprotected digital contents and provides these contents for business use after their encryption. If it has r contents, namely, M1, M2,..., Mr with their unique identity idM1 , idM2 ,..., idMr . Then, he gener- ates r symmetric keys K1, K2, K3,... , Kr and encrypts each content with an unique symmetric key and gets Esym(Mi|Ki), i = 1, 2, 3,..., r. { | } Content provider provides content decryption keys (key seeds) with usage rules and permissions to the license server through a secure channel. Distributor achieves encrypted contents Esym(Mi Ki), for all i = 1, 2, 3,..., r with con- tent information from the Packager. Distributors keep protected contents over the media server and display content details over the website. To communicate securely in the system, entities achieve their secret partial keys with the help of packager and generates their public and private keys. In this process system usages five algorithms: Setup, Partial private key extract, Set secret value, Set private key and Set public key. Description of key generation process is as follows: Setup: Private key generator (PKG) chooses an arbitrary generator P ∈ G1, selects a master key mk ∈ Zq∗ and sets PK = mkP . It chooses hash functions H1 : {0, 1}∗ → G1∗ , H2 : {0, 1}k × {0, 1}∗ × {0, 1}∗ → {0, 1}n, and H : {0, 1}∗ × {0, 1}∗ × G1 × G1 × G2 → {0, 1}k. Then, PKG publishes system parameters ⟨ ⟩ X0, X0, x(., .), x, X, XX, X0, X0,X and Keep master key mk secret. Partial Private key extraction: License server (L) and user U submit their public identities IDL and IDU to the PKG. Then, PKG verifies the proof of identities. If verification succeeds, then generates the partial private keys in the following way: ∈ – Compute QL = H1(IDL) andQU = H1(IDU ) G∗1 . – By using its master key mk, PKG gener...
Proposed Protocol. In this subsection, we describe the steps involved in detail. A
Proposed Protocol. The target is to achieve higher degree of security by creating one public key for a corresponding private key using the features of ID-PKC [23]. The relevant proposed algorithms are presented in this section. Figure 1 shows the process flows of the proposed key generation and key agreement involved in CL-PKC. KGC executes Setup algorithm to generate master-key and system parameters. Then, it runs Partial-Private-Key-Extract algorithm to extract the partial private key for each entity. Every entity chooses a secret value and computes its public and private key. Subsequently, two entities run key agreement algorithm online in order to share a session key.
Proposed Protocol. To overcome the above-mentioned weaknesses, in this section, we propose a secure and efficient mutual au- thentication and key agreement protocol with smart cards for wireless communications, which consists of parameter-generation phase, registration phase, authenti- cation phase, key agreement phase, and password-change phase.
