# Authorizers In decentralized networks, **secure communication between nodes is essential**. While nodes can freely call each other's RPC methods, it’s often critical to ensure that these communications are **authenticated** β€” meaning every message is cryptographically signed and verified. Authorizers are in-between peer communications and are a powerful tool for security. Custom logic can be built to authenticate who, when, what, or why a node is requesting to responding to communication. Authentication helps prevent a wide range of attacks and ensures that each message truly comes from a trusted peer. *** ### **Why Authentication Matters** #### Without authentication, any node in the network could: * Impersonate another node * Falsify data or responses * Launch large-scale spam or Sybil attacks * Eavesdrop on or manipulate communication between other nodes #### By requiring messages to be signed and verified, subnets can: * Establish **trust** between nodes * Prevent **man-in-the-middle (MITM)** attacks * Prevent **Sybil** attacks * Enforce **staking, reputation, or voting systems** ### **Note** If a subnet uses a specific authorizer or authorizers for communication, any new nodes that come in **must use the same authorizers**; otherwise, **they will be unable to connect**. *** ### **Common Attack Vectors** #### **πŸ” Man-in-the-Middle (MITM) Attack** A MITM attack occurs when an attacker intercepts or relays messages between two nodes without their knowledge. The attacker can read, alter, or inject messages β€” pretending to be the sender or receiver. Authentication with digital signatures ensures that only the legitimate sender could have created the message, making MITM attacks ineffective. #### **πŸ”**Sybil Attack A Sybil attack is a type of security threat where an attacker creates multiple fake identities (also called "Sybils") to infiltrate a network and gain undue influence. This is done by having a single entity (like a computer or user account) control multiple fake identities, making it appear as if there are many distinct, legitimate users. --- # 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.hypertensor.org/subnet-template/authorizers.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.