Implementation Architecture. TREE API is a group key agreement API that implements the cryptographic primitives of TGDH. It contains the following three function calls: – tree new user: called by any new member to generate its context. – tree merge req: called by every group member when a join/merge occurs. It identifies the sponsor unambigu- ously (as described in Section 5.6). It then removes all pairs on its key-path. If the caller is a sponsor, generates new secret share and computes all keys and bkeys on its key-path. This function returns an output token, which is then broadcast to the whole group.
Implementation Architecture. The I/O services and collaboration schema was implemented to allow the system to obtain images directly from on-line cameras, video recorded sequences or as a collection of image files. Applications were constructed to a common paradigm which allowed development of the algorithm modules to occur in different environments (Linux and MS Windows) depending on the developers’ preference. The data exchange uses a common database, which guarantees platform independence but pays a price in system performance, although this did not prove to be a constraint in the SUBITO implementation. Only processing results were exchanged via the system database, the video imagery was accessed using a custom API created for that specific purpose. In general applications implement a simple loop including: • Read image, • Process image frame(s), • Send eXtensible Markup Language (XML) data to the database. Those applications not requiring images simply loop on the database, reading, processing and writing data therein. To support the algorithm testing it was decided while defining the implementation requirements that it would be beneficial to utilise the same I/O API at the developers’ site to support individual algorithm module testing as was to be used in the final implemented system. Thus the developers’ could be confident that the developed modules could correctly access the image streams when integrated with the other component modules. For support of system integration and test a communication framework was defined which provided a flexible mechanism to switch between online and offline operating modes. This combined approach would be used to verify the system performance allowing recorded test video sequences to be submitted to the system and the resulting output data collected. The same data could also be played back offline, with the MMI allowing the operator to examine in detail the system behaviour and outputs. With the implementation requirements defined, the focus of the work then moved to the actual hardware integration. The approach adopted was to separate the logical components forming the physical architecture and provide loose coupling of the modules. The primary requirement was for an efficient yet flexible system, with respect to:
Implementation Architecture. The implementation architecture maps the specific vendor products and component(s) that will be used to develop the solution. The infrastructure components, the database components, and the application components will be mapped to the DIR standards. Deviations will be noted to identify the rational for the deviations. The system management needs and handing the system over for maintenance will also be determined to ease the system into maintenance. When combined, the four views will provide a concise understanding of all stakeholders’ needs while creating a snapshot of what the enterprise should look like. Additionally, it will enable a rapid but thorough review of the entire proposed solution—facilitating well-informed and rapid decisions. The technical architecture and standards developed by the Service Provider will be managed through collaboration with DIR and other stakeholders. Service Provider will establish a governance structure in collaboration with DIR, which will be used to monitor the compliance of the systems utilization of the developed technical architecture and standards and its evolution.
Implementation Architecture. TREE API is a group key agreement API that implements the cryptographic primitives of TGDH. It contains the following three function calls: – tree new user: called by any new member to generate its context. – tree merge req: called by every group member when a join/merge occurs. It identifies the sponsor unambigu- ously (as described in Section 5.6). It then removes all [key, bkey] pairs on its key path. If the caller is a sponsor, generates new secret share and computes all keys and bkeys on its key path. This function returns an output token, which is then broadcast to the whole group. – tree cascade: invoked by every member when a subtractive event happens or when all members try to compute the group key collaboratively. In the former case, this function removes all leaving members and their parents as described in Section 5.3. If the caller is a sponsor, it also tries to compute [key, bkey] pairs on the sponsor’s key-path. In the latter case, this function is called repeatedly until the group key is computed. The underlying communication system is assumed to deal with group communication and network events such as merges, partitions, failures and other abnormalities. 7 We use OpenSSL 0.9.6 [24] as the underlying cryptographic library. In the following Sections (6.2 and 6.3), we show that tree cascade provides robustness against cascaded network events. Since TREE API does not provide its own communication facility, the robustness of the API was tested by simulating random events on a single machine running all group members.
Implementation Architecture. At its core, a U2E-Free money market is a ledger that allows Ethereum accounts to supply or borrow assets, while computing interest, a function of time. The protocol’s smart contracts will be publicly accessible and completely free to use for machines, dApps and humans.
