# Blockchain With the emergence of blockchain and smart contracts, new ways are allowing innovative use cases to be developed. In the case of 4thTech, communication protocols were developed, enabling secure, permissionless and immutable communication. In the case of 4thTech, blockchain transactions are used for on-chain data and message exchange as one communication package (i.e. email, short message or data file transfer) represents one L1/L2 transaction. Blockchain acts as an underlying network infrastructure enabling immutability and transparency of the communication transactions executed by the 4thTech protocols. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://wiki.4thtech.io/architecture/blockchain.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.