H3C Technologies H3C S5120 Series Switches - Manual (Page 512)

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Public Key Configuration
This chapter includes these sections:
z Asymmetric Key Algorithm Overview
z Configuring the Local Asymmetric Key Pair
z Configuring the Public Key of a Peer
z Displaying and Maintaining Public Keys
z Public Key Configuration Examples
Asymmetric Key Algorithm Overview
Basic Concepts
z Algorithm: A set of transformation rules for encryption and decryption.
z Plain text: Information without being encrypted.
z Cipher text: Encrypted information.
z Key: A string of characters that controls the transformation between plain text and cipher text. It
participates in both the encryption and decryption.
Key Algorithm Types
As shown in Figure 1-1 , the information in plain text is encrypted by an algorithm with the help of a key
before being sent. The resulting cipher text is transmitted across the network to the receiver, where it is
decrypted by the same algorithm also with the help of a key to obtain the original plain text.
Figure 1-1 Encryption and decryption
There are two types of key algorithms, based on whether the keys for encryption and decryption are the
same:
z Symmetric key algorithm: The keys for encryption and decryption are the same. Commonly used
symmetric key algorithms include Advanced Encryption Standard (AES) and Data Encryption
Standard (DES).
z Asymmetric key algorithm: The keys for encryption and decryption are different, one is the public
key, and the other is the private key. The information encrypted with the public key can only be
decrypted with the corresponding private key, and vice versa. The private key is kept secret while
the public key may be distributed widely, and the private key cannot be practically derived from the
public key.