The adoption of decentralized cryptocurrency platforms is growing fast, thanks to the implementation of Blockchain technology and smart contracts. It encourages the novel frameworks in a wide range of applications including finance and payment methods such as cash on delivery. However, a large number of smart contracts developed for cash on delivery suffer from fraudulent transactions which enable malicious participants to break the signed contracts without sufficient penalties. A shipper will involve in the system and place a mortgage to ensure reliability. A buyer also pledges an amount of money when making the order. Our process not only ensures the interests of a seller but also prevents a fraud shipper. The penalties will be made in two scenarios: (i) the buyer refuses to receive the commodities without any reliable reasons; and (ii) the shipper attempts to make any modification on the delivered goods during transportation. To help developers create more secure and reliable cash on delivery system, we introduce double smart contracts, a framework rooted in Blockchain technology and Ethereum, to tackle those mentioned problems. We also contribute our solution as an open source software that developers can easily add to their implementation to enhance functionality.

In emerging economies, with the explosion of ecommerce, payment methods have increasingly enhanced security. However, Cash-on-Delivery (COD) payment method still prevails in cash-based economies. Although COD allows consumers to be more proactive in making payments, it still appears to be vulnerable by the appearance of a third party (shipping companies). In this paper, we proposed a payment system based on "smart contract" implemented on top of blockchain technology to minimize risks for parties. The platform consists of a set of rules that each party must follow including specific delivery time and place, cost of delivery, mortgage money; thereby, forcing parties to be responsible for their tasks in order to complete the contract. We also provided a detailed implementation to illustrate the efficiency of our model.

One of the major problems of e-commerce globally is the selling and buying of goods among the parties over the Internet in which the traders may not trust their partners. Cash on delivery allows customers to pay in cash when the product is delivered to their home or a location they choose. This is sometimes called a payment system because customers receive goods before making a payment. This paper investigates a critical verification process issue in the cash on delivery system. In particular, we propose a multi shippers mechanism, which consists of blockchain technology, smart contracts and hyperledger fabric platform to achieve distributed and trustworthy verification across participants in the decentralized markets. Our proposed mechanism is given to not only ensure the benefits of the seller but also prevent shipper's fraudulent. The solution leverages the consistency and robustness of decentralized markets where trust is flexible and effectively controlled. To demonstrate the application and implementation of the proposed framework, we conduct several case studies on real-world transaction datasets from a local computer retailer. We also provide our sources codes for further reproducibility and development. Our conclusion is that the continued integration of multi-shipper mechanism and blockchain technology in the decentralized markets will cause significant transformations across several disciplines.

The Internet of Things is one of the most interesting technology trends today. Devices in the IoT network are often geared towards mobility and compact in size, thus having a rather weak hardware configuration. There are many light weight protocols, tailor-made suitable for limited processing power and low energy consumption, of which MQTT is the typical one. The current MQTT protocol supports three types of qualityof-service (QoS) and the user has to trade-off the security of the packet transmission by transmission rate, bandwidth and energy consumption. The MQTT protocol, however, does not support packet storage mechanisms which means that when the receiver is interrupted, the packet cannot be retrieved. In this paper, we present a broker-less SIP-MBA Platform, designed for micro-service and using gRPC protocol to transmit and receive messages. This design optimizes the transmission rate, power consumption and transmission bandwidth, while still meeting reliability when communicating. Besides, we implement users and things management mechanisms with the aim of improving security issues. Finally, we present the test results by implementing a collect data service via gRPC protocol and comparing it with streaming data by using the MQTT protocol.

Internet of Things (IoT), currently, plays an importance role in our life, also, this is one of the most rapidly developing technology trends. However, the present structure has some limitation -one of these is the communication via clientserver model -the users, devices, and applications using IoT services where all the connection/requirement is managed at IoT service providers. On the one hand, the IoT service providers (e.g., individual, organization) have different method to manage their devices, services, and users. Thus, the unique standard (i.e., communication method among the service providers and between client server) is still the challenge for the developers. On the other hand, Message Queuing Telemetry Protocol (MQTT) that is one of the most popular protocols in IoT deployments, has significant security and privacy issues by itself (e.g., authentication, authorization, as well as privacy problem). Therefore, this paper proposes UIP2SOP -an unique IoT network by using Single Sign-On (SSO) and message queue to improve the MQTT protocol's security problem. Besides, this model allows the organizations to provide the IoT services to connect into a single network but does not change the architecture of organization at all. The evaluation section proves the effectiveness of our proposed model. In particular, we consider the number of concurrent users publishing messages simultaneously in the two scenarios i) internal communication and ii) external communication. In addition, we evaluate recovery ability of system when occurred broken connection. Finally, to engage further reproducibility and improvement, we share a complete code solution is publicized on the GitHub repository.