sessioonivõti

A sessioonivõti, often translated as session key, is a temporary cryptographic key used to encrypt communication within a specific session. It is a crucial component of many secure communication protocols, such as Transport Layer Security (TLS) and Secure Shell (SSH). The primary purpose of a session key is to establish a secure channel for data exchange between two parties without requiring them to repeatedly perform computationally expensive public-key cryptography operations.

The lifecycle of a sessioonivõti typically begins with a key exchange process. During this phase, the two communicating parties use a more robust, often asymmetric, encryption method (like Diffie-Hellman or RSA) to securely negotiate and agree upon a shared secret. This shared secret is then used to derive the sessioonivõti. Once established, this sessioonivõti is used for symmetric encryption of all subsequent data transmitted during that session. Symmetric encryption is significantly faster than asymmetric encryption, making it ideal for high-volume data transfer.

The sessioonivõti is, by design, temporary. It is only valid for the duration of the current session. Once the session is terminated, the sessioonivõti is discarded. This limited lifespan enhances security by minimizing the impact of a potential compromise. If a sessioonivõti were to be compromised, the attacker would only gain access to the data exchanged within that specific session, not to any past or future communications. This ephemeral nature is a core security principle in modern secure communication.