Des/3des/aes differences

DES

　　1977 year 1 month , The United States government promulgated ： Adopt IBM The scheme designed by the company is the official data encryption standard for non confidential data （DESData Encryption Standard) .

　　 Currently in China , With the launch of the three gold projects, especially the gold card project ,DES Algorithm in POS、ATM、 Magnetic card and smart card （IC card ）、 Gas station 、 Highway toll stations and other fields are widely used , In order to achieve the confidentiality of key data , Such as the credit card holder's PIN Encrypted transmission of ,IC Card and POS Two way authentication between 、 Financial transaction data package MAC Verification, etc , All used DES Algorithm .

 

　　DES There are three entry parameters of the algorithm ：Key、Data、Mode.

　　 among Key by 8 Bytes in total 64 position , yes DES Working key of algorithm ;

　　Data Also for the 8 Bytes 64 position , Data to be encrypted or decrypted ;

　　Mode by DES How it works , There are two kinds of ： Encrypt or decrypt .

 

　　DES The algorithm works like this ：

　　 Such as Mode For encryption , Then use Key Go get the data Data To encrypt , Generate Data In the form of a password （64 position ） As DES Output result of ;

　　 Such as Mode To decrypt , Then use Key Go to the data in the form of password Data Decrypt , Revert to Data In clear code form （64 position ） As DES Output result of .

　　 At both ends of the communication network , Both parties agree Key, At the source of communication Key The core data is DES encryption , Then in the form of password in the public communication network （ Such as the telephone network ） To the end of the communication network , When the data reaches the destination , Use the same Key Decrypt password data , It reproduces the core data in clear code form . such , It ensures the core data （ Such as PIN、MAC etc. ） Security and reliability of transmission in public communication network .

　　 By regularly switching to new ones at the source and destination of the communication network at the same time Key, It can further improve the confidentiality of data , This is the popular practice of financial trading networks .

 

 

3DES

　　3DES yes DES A mode of encryption algorithm , It USES 3 strip 64 The key of bit encrypts the data three times . Data encryption standard （DES） It is a long-standing encryption standard in the United States , It uses symmetric key encryption .

　　3DES（ namely Triple DES） yes DES towards AES Transitional encryption algorithm （1999 year ,NIST take 3-DES Specified as a transitional encryption standard ）, yes DES A safer variant of . It uses DES For basic modules , We design a group encryption algorithm by combining groups .

 

　　

 

AES

　　AES(Advanced Encryption Standard)： Advanced encryption standard , Is the next generation of encryption algorithm standards , Fast , High level of security .

　　 use AES encryption 2000 year 10 month ,NIST（ The American National Institute of standards and Technology ） Announced from 15 A new key encryption standard selected from three candidate algorithms .Rijndael Selected to be the future AES.Rijndael Is in 1999 In the second half of , By researchers Joan Daemen and Vincent Rijmen Created .AES It is increasingly becoming the actual standard for encrypting various forms of electronic data .

　　 American Institute of standards and Technology （NIST） On 2002 year 5 month 26 A new advanced encryption standard was formulated on the th （AES） standard .

 

　　AES The algorithm is based on permutation and permutation . array Is to rearrange the data , substitution Is to replace one data unit with another .

　　AES Several different methods are used to perform permutation and permutation operations .AES It's an iterative 、 Password of symmetric key packet , It can be used 128、192 and 256 A key , And use 128 position （16 byte ） Group encryption and decryption data .

　　 Unlike public key encryption, which uses key pairs , Symmetric key cryptography uses the same key to encrypt and decrypt data . The number of bits of encrypted data returned through block cipher is the same as the input data . Iterative encryption uses a circular structure , In this loop, the input data is replaced and replaced repeatedly .