What is asymmetric encryption, what is a public key, what is a key

Encryption-Re-encodes the information in some way. Decryption-Restores the encoded information in some way.

What is symmetric encryption and what is asymmetric encryption? Give me a chestnut:

A send a message to B, in order to secure the transmission of information to be encrypted. There are two ways in which they

1. Both A and B know how to encrypt information and how to decrypt it.

A, b all know the password case, a to a piece of information encryption and send, b after receiving a password to decrypt.

2. A only know how to encrypt information, do not know how to decrypt; b Not only knows how to encrypt but also knows how to decrypt it.

b through an algorithm to generate encryption and decryption method, and then the encryption to tell a, let a send him a message, and then he decrypted later to view.

A can only send messages, B can only see messages, asymmetry. The encryption method becomes the public key, and the decryption method becomes the key.

For A and B, the 1th approach is symmetric to each other, and the 2nd way is one-way asymmetric.

Implementation of asymmetric encryption in SSL protocol: to be continued

Implementation of asymmetric encryption in SSH protocol: to be continued

What is asymmetric encryption, what is a public key, what is a key