# Blockchain for Doping Control Applications in Sports: A Conceptual Approach
## 3 Blockchain-Based Approach for the AD Domain
### Design of a Decentralized Anti-Doping Ecosystem
#### 3.3.3 Chaincode and Asset Lifecycle Design  
In Section 2.3, different vulnerable data sharing processes within the AD domain were exemplified. In this paper, the focus was placed on one of these processes, the request for a Therapeutic Use Exemption (TUE). A TUE may be granted to an international athlete, for example, after being submitted to the scrutiny of the medical committees at the International Federation (IF TUEC) and WADA (WADA TUEC) [56]. If granted by both organizations, the athlete is allowed to use medication that otherwise would be forbidden due to possible doping effects. If not granted, the athlete can appeal to the Court of Arbitration for Sports (CAS) [56]. The data submitted and the outcomes within this process are kept as confidential as possible [56; 58]. The reason for choosing this specific process over others is that, as suggested by the AD literature, athletes, their doctors, and trainers show enormous concern in sharing medical data with others through the existing process [5; 49; 50]. The current process for submitting and obtaining a TUE is not fully harmonized, meaning that different organizations may adopt different procedures, and the data are exchanged via paperwork-based forms and e-mail-based communications, resulting in the insufficient anonymization of athletes' data. The data can often leak or be disclosed inappropriately due to such vulnerabilities within the process [5; 49; 50]. With a fully digitalized approach and blockchain, the same process can be redesigned to enhance data integrity, assurance, security, and confidentiality. The TUE request process can be mapped as a SC (Chaincode) logic in HLF [84]. The Chaincode must be designed and coded with the purpose to validate each stage of the TUE request. The Chaincode is installed and instantiated in the peer nodes participating and endorsing the process. From this perspective, the TUE becomes a digital asset in HLF that has a clear lifecycle  
Figure 4: General network architecture for consortium application in HLF, with an example with different channels for different applications. References: [14; 74]. (a sequence of stages). At each stage, the participating organizations contribute with data and the Chaincode is invoked via the decentralized application to modify the asset's attributes accordingly. The following logical sequence is proposed:  
1. Submission Stage: The athlete's doctor submits the TUE request to the applicable International Federation (IF). The asset is transferred by the doctor to the IF, and this transference is a transaction recorded on the blockchain. 2. Receipt Stage by IF: The TUE request is received by the IF at the administrative level. The TUE request details can be analyzed by the IF administrative members with the correct credentials (the doctor's and the athlete's identities should not be disclosed). This allows the IF to determine the IF TUEC medical competences needed to properly evaluate the TUE request. Once the competences are defined, the IF determines the IF TUEC composition. The asset is transferred to the IF TUEC to be analyzed by their members; the transaction is recorded on the blockchain. 3. Receipt Stage by IF TUEC: The IF TUEC receives the asset, performs its analysis, grants, or rejects the request. The analysis and decision are recorded, and the asset is transferred to the next organization, in this case WADA. The transference transaction is recorded on the blockchain. 4. Receipt Stage by WADA: The asset is received by WADA at the administrative level. WADA administrative members with the correct credentials can view the asset's content, the IF TUEC analysis and decision, and determine their own WADA TUEC. The asset is transferred to the WADA TUEC; the transaction is recorded on the blockchain. 5. Receipt Stage by WADA TUEC: The WADA TUEC analyses the IF TUEC response, performs, and records their own analysis and decision (uphold or revert the IF TUEC decision).