# Secure and Privacy-Protected Bioinformation Implementation in Air Passenger Transport Based on DLT
## 3 Framework Architecture
### The DLT Framework  
Air passenger transport involves the cooperation of multiple parties, including airlines, airports, ground-handling companies, and government agencies. They interconnect and work together to ensure safe and efficient trips for passengers. During a trip, passengers go through several stages, including booking, check-in, security screening, boarding, and baggage claim. At each stage, data sharing between different parties is required to ensure smooth operations. For example, airlines and airports must share data for coordinating flight schedules, gate assignments and other operational details; and airlines must share API and Passenger Name Records (PNR) with government agencies for border control or security processing. As DLT is distributed and decentralized, it is suitable for modelling the storage of air passenger transport. This project uses Corda as the DLT development platform [19]. Compared to other platforms such as Hyperledger Fabric, Multichain, or Quorum, Corda has unique advantages [20; 21; 22]. It incorporates smart contracts with legal prose, taking into account highly regulated environments. Considering that the participants of this system include government organizations such as border control and that it transmits sensitive private information, this function is crucial for addressing potential legal provisions in the future. Additionally, as a permissioned DLT platform, it enables users to build permissioned networks while creating applications that can solve business problems operating on it. Corda's point-to-point privacy architecture ensures that data are shared only among relevant parties and that all data are kept accurate over its lifecycle. In comparison, Multichain is typically a public blockchain system and is not as strong in terms of privacy as Corda. This system faces high-frequency processing tasks, and Corda offers efficient transaction processing capabilities through point-to-point transactions and a mechanism that does not require full network consensus. On the other hand, Hyperledger Fabric, due to its consensus mechanisms, does not perform as well as Corda under high concurrency. In terms of implementation, platforms like Quorum have weaker compatibility, often requiring additional adaptation and development work. Moreover, Corda has a larger community and wider application. Application networks are discrete instances of a permissioned collective associated with one or more applications. As Figure 1 shows, these application networks are associated with Corda Distributed Applications (CorDapps). A CorDapp is an application that solves a specific problem using the Corda framework. CorDapps are stored on Corda nodes and executed on the Corda network. Unlike traditional apps which utilize one dedicated system to achieve an assigned task, this structure can distribute apps and allow them to run on multiple systems simultaneously. An application network is composed of nodes, which represent the participants in the network. In order to cope with the large volume of interactions as well as the work requirement, each party in air passenger transport can run a cluster of nodes, with a node or several nodes specialized for one or more CorDapps. Each node in the same Cluster handles different tasks or the same business for different interactions. The node here is associated with a virtual node in the Corda infrastructure, which stores its data, specifically its view of the distributed ledger, in its database vault. Nodes communicate with each other using peer-to-peer communication, which is encrypted using Transport Layer Security (TLS). This allows nodes to send messages directly to each other, without the need for global broadcasts to all nodes on the network [23; 24]. A CorDapp is composed of two layers, an orchestration layer for business logic and a consensus layer that defines rules for updating the ledger. There are some basic components of a CorDapp, including Flows, States and Contracts.