The 1 and DES algorithms have three entry parameters: Key, Data and Mode.
Where Key is 7 bytes ***56 bits, which is the working key of DES algorithm; The data is 8 bytes and 64 bits, which is the data to be encrypted or decrypted; Mode is the working mode of DES, and there are two ways: encryption or decryption.
2. The basic requirement of 2.AES is to adopt symmetric block cipher system, with the key length of at least 128,192,256 and the block length of 128 bits. The algorithm should be easy to implement in various hardware and software.
Therefore, the key length of AES is longer than DES, and it can also be set to any multiple of 32 bits, with the minimum value of 128 bits and the maximum value of 256 bits, which cannot be cracked by exhaustive method.
Second, the running speed is different.
1, as a block cipher, DES? Encryption unit is only 64? Bit binary, which is too small for data transmission, because each packet only contains 8? Characters, some of which are also used for parity or other communication overhead. Processing speed is slow and encryption is time-consuming.
2.AES has very low memory requirements and fast operation speed. Rijndael shows excellent performance in both hardware and software in feedback mode and no feedback mode.
Third, the scope of application is different
1, data encryption standard, fast, suitable for encrypting a large number of data. DES is fragile in security, but due to the mass production of fast DES chips, DES can still be used temporarily. In order to improve the security strength, three-level DES with independent keys is usually adopted.
2.AES is suitable for small 8-bit single chip microcomputer or ordinary 32-bit microprocessor, suitable for special hardware implementation, and its throughput (the number of encryption/decryption bits per second) can reach one billion. Similarly, it is also suitable for RFID systems.
Baidu encyclopedia -DES
Baidu encyclopedia -AES