Multipoint-to-multipoint secure-messaging with threshold-regulated authorisation and sabotage detection

This paper presents multi-user protocol-extensions for Schnoff/Nyberg-Ruepple (NR) signatures and Zheng signcryption, both of which are elliptic curve (EC)/discrete logarithmic (DL) formulations. Our extension methodology is based on k-of-n threshold cryptography-with Shamir polynomial parameterisation and Feldman-Pedersen verification-resulting in multi-sender Schnorr-NR (SNR) and multi-sender/receiver Zheng-NR (ZNR) protocols, all of which are interoperable with their single-user base formulations. The ZNR protocol-extensions are compared with the earlier Takaragi et al multi-user sign-encryption, which is extended from a base-protocol with two random key-pairs following the usual specification of one each of signing and encryption. Both single and double-pair formulations are analysed from the viewpoint of EC equivalence (EQ) establishment, which is required for rigorous multi-sender functionality. We outline a rectification to the original Takaragi et al formulation; thereby enabling parameter-share verification, but at significantly increased overheads. This enables comprehensive equivalent-functionality comparisons with the various multi-user ZNR protocol-extensions. The single-pair ZNR approach is shown to be significantly more efficient, in some cases demonstrating a two/three-fold advantage

Public safety mobile broadband: draft report

The draft report was released on 23 September 2015. You are invited to examine the report and to make written submissions by Wednesday 28 October 2015. This draft report looks at the best way to deliver a Public Safety Mobile Broadband (PSMB) capability for emergency services that is reliable, interoperable and works across Australia. The final report will be released in December 2015. Key points Public safety mobile broadband (PSMB) holds considerable potential to improve how the police, fire, ambulance and other public safety agencies (PSAs) deliver their services. It will allow frontline officers to access high-speed video, images, location tracking and much more. PSAs currently rely on their own radio networks for voice communications and some low-speed data. Mobile broadband use has been modest due to concerns that the quality of commercial services is insufficient to support \u27mission critical\u27 operations. The network capacity that PSAs require is uncertain. PSAs are seeking a higher quality of service than what is currently available on commercial networks. However, the standards required (in terms of coverage, reliability, security, priority access and so on) are not specific. There are many ways to provide a PSMB capability, including the construction of a dedicated network, a commercial approach, or some combination (hybrid) of the two. A dedicated network would give PSAs access to (and control over) their own PSMB network using their own parcel of spectrum. A commercial approach would mean that PSAs obtain PSMB services from one or more of the commercial mobile carriers through a contract for service. The Commission has undertaken an illustrative evaluation of the costs of several specific delivery options over a 20-year period. The cost of a dedicated network was estimated to be in the order of $6.1 billion, compared to$2.1 billion for a commercial option. Even the lowest-cost hybrid option is twice as expensive as a commercial option. A commercial option is cheaper because it requires significantly less \u27new investment\u27 than a dedicated or hybrid option as considerable existing infrastructure could be used or shared. Risk factors also influence the relative merits of different options. A dedicated network would likely take longer to deliver and offer less flexibility to scale up network capacity in the short term, relative to other options. Providing priority services under commercial or hybrid options would be more technically complex than under a dedicated option. There are also commercial risks arising from limited competition and supplier \u27lock-in\u27. The benefits of each option are not expected to vary markedly, since the options under evaluation have been designed to deliver a similar level of PSMB capability. On that basis, the cost evaluation is likely to provide the best guide to net community benefit for each option. On first principles, a commercial approach represents the most efficient, effective and economical way of delivering a PSMB capability to PSAs. Small-scale trials would provide an opportunity for jurisdictions to gain confidence in a commercial approach; gauge the costs, benefits and risks of PSMB; and develop a business case for a wider-scale roll out. Competitive procurement is essential. Splitting up tenders, leveraging infrastructure assets and insisting on open technology standards can help governments secure value for money. Achieving interoperability will require jurisdictions to agree on common technical standards. PSAs will also need to adapt their operations to make the most of PSMB. This includes protocols for sharing information and network capacity among agencies. Spectrum allocation is an Australian Government responsibility. Any spectrum made available for PSMB should be priced at its opportunity cost to support its efficient use