List of cryptosystems
# List of cryptosystems

A cryptosystem is a set of cryptographic algorithms that map ciphertexts and plaintexts to each other.

## Private-key cryptosystems

Private-key cryptosystems use the same key for encryption and decryption.

* Caesar cipher
* Substitution cipher
* Enigma machine
* Data Encryption Standard
* Twofish
* Serpent
* Camellia
* Salsa20
* ChaCha20
* Blowfish
* CAST5
* Kuznyechik
* RC4
* 3DES
* Skipjack
* Safer
* IDEA
* Advanced Encryption Standard, also known as AES and Rijndael.

## Public-key cryptosystems

Public-key cryptosystems use a public key for encryption and a private key for decryption.

* Diffie–Hellman key exchange
* RSA encryption
* Rabin cryptosystem
* Schnorr signature
* ElGamal encryption
* Elliptic-curve cryptography
* Lattice-based cryptography
* McEliece cryptosystem
* Multivariate cryptography
* Isogeny-based cryptography
