home/dictionary/Ephemeral Key

Ephemeral Key

nouncandidate·updated May 12, 2026

A cryptographic key that is generated for each execution of a key establishment process and that meets other requirements of the key type (e.g., unique to each message or session). In some cases, ephemeral keys are used more than once within a single session (e.g., broadcast applications) where the sender generates only one ephemeral key pair per message, and the private key is combined separately with each recipient’s public key.

Framework senses

NISTIR 7298: Glossary of Key Information Security Terms, Revision 21 senseview framework →
§1
A cryptographic key that is generated for each execution of a key establishment process and that meets other requirements of the key type (e.g., unique to each message or session). In some cases, ephemeral keys are used more than once within a single session (e.g., broadcast applications) where the sender generates only one ephemeral key pair per message, and the private key is combined separately with each recipient’s public key.
NIST SP 800-57 Part 11 senseview framework →
§1
A cryptographic key that is generated for each execution of a key establishment process and that meets other requirements of the key type (e.g., unique to each message or session). In some cases, ephemeral keys are used more than once within a single session (e.g., broadcast applications) where the sender generates only one ephemeral key pair per message, and the private key is combined separately with each recipient’s public key.