A detailed explanation of DES encryption and decryption algorithm

In recent time because the project needs, so has been committed to the network and information security, inevitably involved in information encryption and decryption, so these days have been hard to delve into cryptography.

Cryptography is an ancient discipline, in the history of cryptography development, there have been a variety of encryption methods, and very early classical encryption algorithm, and then appeared more mature group password, public key password and stream password, etc., because I only involved in the packet public key password, so in this article on the first introduction of the block password, Before the group password to say is a common cryptography in the two systems, one is the symmetric cipher system, a asymmetric cryptosystem, also known as Public key cryptography system.

Symmetric cryptography means that if a cryptographic system has the same cryptographic key and encryption key, or though it is different, any one of them can easily derive another, that is, the key is shared by both parties.

Next I will introduce a symmetric cipher algorithm des.

Its algorithm describes des