What is a replay attack?

A replay attack is a form of network attack in which an attacker captures and replays data transmissions between two parties in order to gain unauthorized access to a system or forge transactions.

In a replay attack, the attacker intercepts data packets, such as login credentials or transaction requests, and then later resends these packets to the target system as if they were from the original sender. This can allow the attacker to impersonate the legitimate user and gain access to sensitive information or carry out unauthorized actions.

To protect against replay attacks, cryptographic protocols such as secure sockets layer (SSL) and transport layer security (TLS) are often used to encrypt data transmissions and prevent unauthorized interception and replay. Additionally, implementing message authentication codes (MACs) or timestamping can help prevent replay attacks by ensuring the integrity and freshness of data transmissions.