# A Blockchain Self-Sovereign Identity for Open Banking Secured by the Customer's Banking Cards
## 7 Discussion and Evaluation
### Analysis and Comparison  
KYC2 [18] advised the need for key management, secret handling, and recovery options. This work proposes using banking smart cards for identity cryptographic operations and deploying the SSI concept based on Ethereum Blockchain; in particular, the curve exists for multiple-market banking Java Cards, which we validated in this proof of concept.  
SCARAB [21] stores everything on-chain. This affects the scaling and system performance; furthermore, it stores identity-sensitive data on public servers, with no possibility to erase them.  
BBM [5] is a Blockchain SSI model for open banking; however, SSBI uses the banking card, which is trusted and available to use by the customer for daily purchases. This work extends the use of the card to store and manipulate the identity transaction signing and allows the sharing of VCs with third parties through the Veramo SSI platform. This achieves the balance between usability and assurance without additional hardware tokens. This work attempted to implement a prototype, and to assess its feasibility and possibility of being integrated with the existing banking card issuance process.  
The SSI framework prevents banking scam calls [7]. We leverage its use case and overcome the limitation of the signing curve on Java Card ED25519, which is required for Indy transactions. Instead, the framework is based on Veramo and Ethereum Blockchain, for which the required SECP256K1 signing curve exists in several banking cards, to issueethr DIDs and VCs. This fits within open banking use cases, and the proposed framework supports smart contracts to enable automated online financial services.  
In [22], the authors proposed a protocol to achieve a high level of assurance (LoA) by combining a software wallet key part and a YubiKey 5 Ci token [23] hardware key part. In contrast, in SSBI we leverage the banking use case and balance the usability and strong security without additional devices. Moreover, the framework supports strong authentication and VC exchange for open banking services, and not only the identity operations.  
The authors in [24] proposed \"Casper\", a mobile identity wallet that enables interbanking Know Your Customer (KYC) based on SSI. In this work, we combine high LoA using banking cards to improve the identity control and share a payment experience that is similar to that of using banking cards to support extension to several business values, such as smooth KYC, password-less login to mobile banking, and much more. We rely on Ethereum Blockchain, and the Veramo SDK to handle DIDs and VCs. In addition, we use a key recovery mechanism that combines a secret part from the bank with a known passphrase held by the customer.  
PriFob [25] is a global online credential management solution that provides privacy, which is fog-enhanced and based on a publicly permissioned Blockchain. The efficiency and performance improved due to the adaptation of PoA and SoW consensus protocols. Although it is not applied directly for the banking use case, we focus on improving security and the customer experience by involving banking cards in the flow of identity sharing. However, the reliable encryption scheme and consensus algorithm in PriFob can be utilized in our future improvements to achieve better scalability.  
A comparative analysis between SSBI and the previous work is summarized in Table 1.