Common use of Security Properties Clause in Contracts

Security Properties. In GKA protocols, the fault tolerance property is very crucial since it is necessary to detect and eliminate malicious participants from the key agreement group. In other words, even if there are malicious participants in the group, they should not be able to affect the key computation of honest participants. Early protocol examples with this property are [24–26]. In this regard, in ▇▇▇▇▇’▇ protocol [24], every participant keeps a verification matrix ▇▇▇. After the secret key distribution step, each participant checks the signature of other participants. According to the result, the verification list is marked and submitted to other participants. Afterwards, in the fault detection step, participants re-validate the verification matrix and remove the faulty participants from the key agreement group. Finally, GKA protocol is started from scratch with the remaining participants. Forward secrecy (also stated as Perfect forward secrecy) is also a substantial property that protects against the computation of group keys by malicious actors even if private keys are compromised. Forward secrecy is utilized in protocols presented in [4, 27, 28]. Dynamic group key operations in group key agreement protocols must provide forward and backward confidentiality properties defined in Section 2.1.1. Introduced by ▇▇▇▇▇ et al., KAP-PBC [11] protocol provides these properties within its dynamic operations. In join and leave operations, last participants in the group re-compute the GKA parameters. Therefore, joined participants cannot compute the former group keys, and leaving participants cannot generate the subsequent keys. Moreover, KAP-PBC provides ‘Partial Backward Confiden- tiality’ property, which enables the participants to compute the group keys just before joining the group.

Security Properties. In GKA protocols, the fault tolerance property is very crucial since it is necessary to detect and eliminate malicious participants from the key agreement group. In other words, even if there are malicious participants in the group, they should not be able to affect the key computation of honest participants. Early protocol examples with this property are [24–26]. In this regard, in ▇▇▇▇▇’▇ protocol [24], every participant keeps a verification matrix ▇▇▇. Vi j. After the secret key distribution step, each participant checks the signature of other participants. According to the result, the verification list is marked and submitted to other participants. Afterwards, in the fault detection step, participants re-validate the verification matrix and remove the faulty participants from the key agreement group. Finally, GKA protocol is started from scratch with the remaining participants. Forward secrecy (also stated as Perfect forward secrecy) is also a substantial property that protects against the computation of group keys by malicious actors even if private keys are compromised. Forward secrecy is utilized in protocols presented in [4, 27, 28]. Dynamic group key operations in group key agreement protocols must provide forward and backward confidentiality properties defined in Section 2.1.1. Introduced by ▇▇▇▇▇ et al., KAP-PBC [11] protocol provides these properties within its dynamic operations. In join and leave operations, last participants in the group re-compute the GKA parameters. Therefore, joined participants cannot compute the former group keys, and leaving participants cannot generate the subsequent keys. Moreover, KAP-PBC provides ‘Partial Backward Confiden- tiality’ property, which enables the participants to compute the group keys just before joining the group.