Symmetric Key
Definition
One shared secret used to both encrypt and decrypt. Fast (AES-128 on AES-NI runs at multiple GB/s) but solves nothing if the two parties have no prior secure channel to exchange the key.
Related terms
- Asymmetric Key Pair
- Mathematically linked public and private keys. The public key encrypts or verifies, the private key decrypts or signs. Two to three orders...
- CIAN
- Confidentiality, Integrity, Authentication, Non-repudiation. The four properties a cryptosystem can deliver, usually not all at once with a single primitive. Bulk encryption...
- Confusion and Diffusion
- Shannon's 1949 design principles. Confusion makes the relationship between key and ciphertext as complex as possible; diffusion spreads each plaintext bit's influence...
- Hybrid Encryption
- The pattern every real protocol uses: asymmetric crypto exchanges a fresh symmetric session key, then the symmetric primitive does the heavy lifting...
- Perfect Forward Secrecy
- A property where compromise of a long-term key does not retroactively break past sessions, because each session used an ephemeral key (typically...
Explained in
- Cryptography: Symmetric vs Asymmetric, Substitution, TranspositionOne shared secret used to both encrypt and decrypt. Fast (AES-128 on AES-NI runs at multiple GB/s) but solves nothing if the two parties have no prior secure c...