Key distribution is the process of securely delivering encryption keys to parties that need them for cryptographic communication. It is a critical component of cryptographic systems, ensuring that only authorized users can access the keys.

There are various methods of key distribution:

Manual Key Distribution: Keys are physically delivered or pre-installed on devices. While secure, this approach is impractical for large-scale systems.
Symmetric Key Distribution: Involves sharing a single secret key between parties. This method requires a secure channel for the initial exchange.
Asymmetric Key Distribution: Public-key infrastructure (PKI) uses public and private keys to distribute keys securely over untrusted networks.
In modern systems, key distribution often relies on trusted third parties, such as Certificate Authorities (CAs) in PKI, to authenticate identities and manage keys. Secure protocols like Diffie-Hellman and Elliptic Curve Cryptography (ECC) further enhance the process by enabling secure key exchanges without the need for pre-shared secrets.

Effective key distribution minimizes risks such as interception, unauthorized access, and cryptographic attacks. It underpins the security of systems like TLS, email encryption, and secure messaging platforms.