Introduction - If you have any usage issues, please Google them yourself
MD5 allows large capacity information to be compressed into a secret format before signing a private key with a digital signature software (that is, converting a string of any length into a large integer of a certain length). Whether it's MD2, MD4, or MD5, they all need to get a random length of information and produce a 128 bit summary of the information. Although these algorithms are more or less similar in structure, the design of MD2 is quite different from that of MD4 and MD5, because MD2 has been designed for 8 bit machines, while MD4 and MD5 are 32 bit computers.