The Caesar Cipher, Enigma and AES are all symmetric encryption.

Caesar Cipher、Enigma 和AES 都是对称加密。

So, now you know all the “key” parts of modern cryptography: symmetric encryption, key exchange and public-key cryptography.

所以，现在您了解了现代密码学的所有“关键”部分：对称加密、密钥交换和公钥密码学。