MD5 value is a widely used cryptographic hash function, which can generate a 128-bit (16-byte) hash value to ensure complete and consistent information transmission.

the value of MD5 is that it adds the concept of "safety belt" to MD4. MD5 is more complicated than MD4, but it is safer. This algorithm obviously consists of four steps slightly different from MD4 design. In MD5 algorithm, the necessary conditions for the size and filling of information-digest are exactly the same as MD4.

Extended data

MD5 value principle

The principle of MD5 algorithm can be briefly described as follows: MD5 code processes the input information in 512-bit groups, and each group is divided into 16 32-bit groups. After a series of processing, the output of the algorithm consists of four 32-bit groups, and a 128-bit hash value will be generated by concatenating these four 32-bit groups.

in MD5 algorithm, firstly, information needs to be filled, and this data is supplemented by bits, and the result of modulo 512 is required to be 448.

that is to say, after the data is supplemented, its bit length is only 64 bits, which is an integer multiple of 512. Even if the number of digits of this data modulo 512 is exactly 448, it must be supplemented.

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