> For the complete documentation index, see [llms.txt](https://scalaris.gitbook.io/scalaris/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://scalaris.gitbook.io/scalaris/overview/scalaris-framework/mev-mitigation-in-the-scalaris-framework/mev-in-old-bft-based-blockchains.md).

# MEV in Old BFT-Based Blockchains

In these systems, the leader can follow the protocol while manipulating the transaction order and block contents for financial gain. This centralized decision-making allows the leader to benefit at the expense of transaction fairness.