P2P (Peer-to-Peer) is a decentralized communication model in which each participant (or node) can act as both a client and a server, sharing resources directly without relying on a central authority or intermediary. In a P2P network, participants interact directly with each other to exchange data, files, or services.

Key Characteristics of P2P:

Decentralization: No single server or central authority. All nodes have equal status.

Resource Sharing: Nodes share resources such as files, bandwidth, or computing power.

Scalability: P2P systems can scale well because new participants contribute additional resources.

Resilience: Decentralization makes it less vulnerable to failures or attacks on a single point.

Common Use Cases:

File Sharing: Platforms like BitTorrent allow users to share large files efficiently.

Cryptocurrency: Bitcoin and other blockchain technologies operate as P2P networks.

VoIP and Messaging: Tools like Skype initially used P2P to establish direct connections between users.

Distributed Computing: Projects like SETI@home use P2P to harness computing power from many devices.

Decentralized Applications (dApps): Applications on platforms like Ethereum use P2P for blockchain transactions.

Advantages of P2P:

Cost-efficient as no central server infrastructure is required.

Resilient to censorship and single points of failure.

Facilitates faster file transfers when many nodes participate.

Challenges of P2P:

Harder to regulate or control, which can lead to misuse.

Security concerns like data privacy and malware distribution.

Dependence on the availability of peers for performance.

In modern contexts, P2P systems are foundational to decentralized technologies like blockchain and Web3.