# A Multi-Layer Secure Sharing Framework for Aviation Big Data Based on Blockchain
## 3 Analysis of ATM Big Data Sharing
### Foundation of Aviation Big Data Sharing
#### 3.2.3 Demand Analysis  
These trends render traditional sharing mechanisms inadequate for new scenarios. While ICAO Annex 11 only specifies minimum security requirements for data sharing, new operational needs like multi-party situational awareness and collaborative decision-making have generated additional demands for ATM data sharing.  
1. Hierarchical sharing requirements.  
Layered data sharing accommodates differentiated business needs among ATM participants, divided into raw data sharing and data-model sharing.  
Participants can be categorized into three tiers, core operational entities, collaborative support entities, and regulatory (research) entities, forming a \"decision-execution-supervision\" tri-layer structure. This reflects ATM's multi-level data-sharing requirements--different entities have varying demands for data granularity and timeliness. Core operators rely on high-precision real-time data to maintain operational safety (e.g., airlines needing second-level latency for airspace restriction updates), while regulators focus more on data trends, requiring aggregated historical data for decision models. The former necessitates direct raw data sharing, whereas the latter prefers model sharing, achieving information exchange through distributed model training while keeping raw data localized.  
Raw data sharing ensures complete transmission of critical operational data to consumers, while model sharing minimizes unnecessary information leakage, adhering to the \"data minimization principle\" and transforming sharing from \"ownership transfer\" to \"usage rights sharing.\"  
This hierarchical approach balances data openness with ownership control through data-model separation, offering new solutions to break \"data silos\" and laying groundwork for differentiated security strategies.  
Information security requirements.  
The expanded sharing scope significantly increases attack surfaces, multiplying ATM system security risks. Recent years have seen growing information security incidents in global aviation, causing substantial economic losses and even threatening flight safety. In September 2016, DHS senior officials confirmed successful remote penetration testing on a Boeing 757 at Atlantic City International Airport via radio communications. In September 2018, Bristol Airport's electronic displays were disabled for two days by ransomware attacks, forcing manual flight information updates. ATM data faces tampering, theft, and access failure risks regarding confidentiality, availability, and integrity. Unauthorized access and privacy breaches during sharing threaten ATM's secure operation.  
Efficiency requirements.  
Aviation operations' characteristics--vast airspace networks, dense traffic flows, cross-regional coordination, and highly dynamic management--impose stringent timeliness demands on data sharing. As ATM systems transition from \"human-led decision-making\" to \"data-driven decision-making,\" exemplified by Trajectory-Based Operations (TBO) requiring real-time 4D trajectory data exchange among ATC, airlines, and airports [31], data timeliness becomes an increasingly critical constraint.  
Storage resource requirements.  
There exists a contradiction between exponentially growing data volumes and limited storage resources. New-generation aircraft generate 5-8 TB data per flight (80 times more than older models), with global fleet data projected to reach 98 billion GB annually by 2026 [32]. This massive historical data imposes high storage demands on aviation participants, especially lightweight users like aircraft avionics systems with inherently limited storage capacity, making storage capacity adaptation a prerequisite for effective data sharing.  
Incentive requirements.  
Due to operational inertia, most data producers are reluctant to share voluntarily. Meanwhile, data consumers remain skeptical about shared data's utility, as current ATM operations lack an effective fair incentive mechanism for data sharing.