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SynAc
Term

Symmetric Key

A symmetric key is a secret key shared between parties and used for both encryption and decryption.

Senses

Shared secret

Symmetric cryptography uses the same key to encrypt and decrypt. It is efficient for bulk data encryption but requires a secure way to distribute and rotate keys.

References
  • NIST CSRC GlossaryJan 05, 2026
    NIST CSRC Glossary — Symmetric key
    https://csrc.nist.gov/glossary/term/symmetric_key
    NIST states most site information is public information and may be distributed or copied, except material marked as copyrighted; attribution requested. Verify per-document markings before quoting.
    Source: NIST CSRC Glossary (csrc.nist.gov).
Sense 2

A cryptographic key that is used to perform both the cryptographic operation and its inverse, for example to encrypt plaintext and decrypt ciphertext, or create a message authentication code and to verify the code.

Also, a cryptographic algorithm that uses a single key (i.e., a secret key) for both encryption of plaintext and decryption of ciphertext.

References
  • NICCS (CISA) Cybersecurity VocabularyJan 06, 2026
    NICCS glossary export (CSV)
    https://niccs.cisa.gov/rest/vocab/export-csv
    NICCS is a CISA (DHS) program. Individual glossary entries include a "From" attribution (e.g., CNSSI 4009, NIST SPs, NICE Framework). Treat "From" values as upstream provenance and verify before quoting large portions of text.
    Source: NICCS (CISA) Cybersecurity Vocabulary (niccs.cisa.gov).