# Proof of Stake The Opera chain is secured using a proof-of-stake (PoS) mechanism. In PoS on Opera, validators must lock their FTM (Opera's native token); if they act maliciously in the network, they lose their tokens. Validators are incentivized to act in the network's best interest as their own funds are at stake. Since validators do not need to perform computations, this approach is a much more energy-efficient alternative to proof-of-work for achieving resistance to Sybil attacks! A **Sybil attack** is an attack where a malicious actor runs a large number of validators to allow them an unsafe amount of influence over the network. PoS makes it costly to set up these validators and allows the network to punish validators for malicious behavior, **increasing the costs of attacks**. Opera requires validator nodes to lock up at least 50,000 FTM to validate transactions and produce blocks. --- # 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://docs.fantom.foundation/technology/proof-of-stake.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.