Alior Bank's Durable Medium

In the European Union, banks are required to provide documents to customers in a format that's not only accessible but also secure and unchangeable. Historically, this was achieved by sending paper versions of the documents or CDs with PDF files. I think we can agree that this was not a solution befitting the 21st century. When I worked at Alior Bank, we revolutionized the process of delivering documents by developing the Trusted Documents Portal.

dokumenty.aliorbank.pl

Alior Bank's Document Portal

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How it works

Each time a public document is published, its hash is stored in Alior Bank's smart contract on the Ethereum blockchain. This hash is then used to verify the authenticity of the document each time the customer requests it through the web portal, available at dokumenty.aliorbank.pl. This process proves that the document has not been altered on the bank's servers since its publication. Of course, since it's a public blockchain, the customer can also verify the document using any Ethereum blockchain explorer, such as Etherscan.

Unique challenges

The biggest challenge was to make the solution user-friendly for the customer. That's why we hid the blockchain part of the solution behind a simple web interface, while still allowing the customer to view more technical information about the document if they wish. Another challenge was to enable the bank to use the solution without the need to handle cryptocurrencies directly. To address this, we partnered with Nextrope to operate a transaction relayer. This arrangement ensured that Nextrope covered the fees by signing the transaction, while the smart contract verified another signature contained within the transaction data.

My role in the project

As the Blockchain Technology Lead at Alior Bank, I worked closely with almost all teams involved in the project. I was responsible for the blockchain side of the project, encompassing the architecture of the solution, the choice of technology, and its implementation. I authored the smart contract, the core of the solution, publicly viewable on Etherscan. Additionally, I developed the first version of the frontend application that allows customers to access their documents authenticated using blockchain technology, as well as a proof of concept for the transaction relayer.

Technology