One-way-linkable blind signature security architecture for VANET

Security attributes of a Vehicular ad hoc network (VANET) include confidentiality, integrity, authentication, non-repudiation (liability), revocation and privacy. Privacy, having characteristics opposing to the rest of the attributes, makes design of a security architecture quite difficult. A commonly used solution is to have a large number of temporary certificates (i.e., pseudonyms) to achieve these security attributes. To guard against their malicious use, these pseudonyms are stored in expensive tamper-proof-devices (TPDs). Further, a large number of valid pseudonyms, at any given time, make non-repudiation and revocation quite complex and difficult to achieve. Another solution is to get pseudonyms blindly signed from a certificate server, thus eliminating the need of TPDs (given the pseudonyms are not generated in bulk). However, blind signatures provide unconditional privacy and thus require complex/multi-transaction procedures to ensure non-repudiation/revocation. We present a security architecture by revising the original Blind signature scheme. Our proposed architecture provides “one-way-link-ability” that helps to achieve all the security attributes without introducing complex/multi-transaction procedures. It does not require expensive TPDs or complex pseudonym issuance/revocation procedures and is especially suited to VANET during initial deployment phase which is characterized with intermittent connectivity. Further, non-repudiation/revocation requires cooperation between multiple entities thus ensuring privacy without a single point of failure.