MD in MD5 stands for Message Digest, which means information digest, but this information digest is not an abbreviation of information content, but a 128-bit feature code obtained by mathematical transformation of the original information according to the published MD5 algorithm.

The characteristic code has the following characteristics. First of all, it is irreversible. For example, I have a ciphertext like My Secret Language. After algorithm conversion, I got the MD5 code (B9944E9367D2e40DD1F0C4040D4 daaf7). Tell others this code, and others will know what your original text is according to this MD5 code.

Mathematical modeling graduate students upload the md5 code of competition papers mainly to prevent the papers from being tampered with. MD5 code is the feature code for submitting papers and supporting materials, and it is the only code to identify the works. If MD5 is modified after submission, it will be discovered, which is a means to prevent cheating and package switching.

The full name of MD5 is Message-Digest Algorithm 5, which was invented by MIT Computer Science Laboratory and RSA Data Security Company in the early 1990s. The practical application of MD5 is to generate a fingerprint for a message (byte string), which can prevent it from being tampered with.