Public Key Infrastructure Clause Samples

Public Key Infrastructure. (PKI) and Public Key (PK) Enabling.

Public Key Infrastructure. We assume that all the parties have access to a public key infrastructure (PKI). That is, parties hold the same vector of pub- lic keys (pk1, pk2, . . . , pkn), and each honest party Pi holds the secret key ski associated with pki.5 A signature on a value v using secret key sk is computed as σ Sign (v); a signature is verified relative to public key pk by calling Verpk(v, σ). For simplicity, we assume in our proofs that the signatures are perfectly unforgeable. When replacing the signatures with real-world instantiations, the results hold except with a negligible failure probability. Coin-Flip. Parties have access to an ideal coin-flip protocol CoinFlip that gives the parties a common uniform random value (in some range depending on the 5 This is a bulletin-board PKI, where the keys from corrupted parties can be chosen adversarially. See [BCG21] for a nice discussion. protocol of choice). This value remains uniform from the adversary’s view until the first honest party has queried CoinFlip. Such a primitive can be achieved from a trusted setup of unique threshold signatures [CKS05, LJY14].

Public Key Infrastructure. ‌ Like many other protocols, DCGKA requires a means for one user to obtain correct public keys for the other group members. These public keys are then used to authenticate messages at the ACB layer, and to initialize the 2SM protocol. We assume that each user is identified by an ID, and we model this module as follows:

Public Key Infrastructure. The public key infrastructure is responsible for generate public & private key pairs and certificates to vehicles. In our solution we assume that all vehicles have been deployed public & private key pairs, and certificates already.

Public Key Infrastructure. (PKI)‌ The notion of public key cryptography was first introduced by ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇ and Mar- tin ▇▇▇▇▇▇▇ in their 1976 seminal paper [21]. Realizing that the proposed public key directory had its shortcomings (both in regard to performance and availability), ▇▇▇▇▇ ▇▇▇▇▇▇▇▇▇▇ introduced the concept of certificates in 1978 [35]. The idea was to allow a certificate authority (CA) to bind a name to a key through a digital signature and store it in a repository. A few years later, certificates were incorporated into X.500, a hierarchical database model for the public key infrastructure (PKI). These certificates (X.509) were designed to address the access control issues of the X.500 directory. The original motivation for PKI was to provide mechanisms for issuing, storing, and distributing public key certificates. Over the years, however, a number of problems [30, 29] with PKI have been discovered. One concerns the identity of the X.509 certificate and how to properly retrieve the desired key should the repository hold certificates with identical names (DN). It is possible to disambiguate names by adding uniquely identifi- able strings or digits such as a user’s Social Security number to the DN, but this again makes it trivial to perform name lookups for third parties. The fact that certificates are based on owner identity also becomes a problem if the owner changes affiliation, e-mail address, or name. Usually, an owner will have several certificates with the same identity.