AES-256-GCM
A symmetric authenticated-encryption construction. AES supplies the block cipher; GCM supplies authenticated encryption and integrity checking. Correct nonce handling is essential.
ECDH
Elliptic-curve Diffie-Hellman is a key-agreement mechanism. Two parties combine private and public key material to derive shared secret material.
ECDSA
Elliptic-curve Digital Signature Algorithm. It provides signatures that can be verified with the corresponding public key.
HKDF
HMAC-based Key Derivation Function. It expands key material into purpose-specific keys and can incorporate contextual information.
Nonce
A value intended to be used once in a cryptographic construction. For AES-GCM, accidental nonce reuse with the same key can be catastrophic.
TLS
The protocol family behind HTTPS and WSS. It protects transport between a client and a service endpoint and authenticates the endpoint using certificates.
TURN
A relay protocol used by WebRTC when a direct network path cannot be established. TURN improves connectivity; it is not itself the application message-encryption scheme.