MD5 Message-Digest Algorithm (English: MD5 Message-Digest Algorithm), a widely used cryptographic hash function, can generate a 128-bit (16-byte) hash value to ensure information transmission Complete and consistent.
The md5 value corresponding to each file is fixed. When the content of the file changes, the md5 value will also change. When the file content is the same, the md5 value is the same. Therefore, the md5 value can be used as a unique identifier for the file.
If you want to know whether the downloaded file is exactly the same as the original file, you can check the md5 value of the file.
If the md5 value of the downloaded file is the same as the published md5 value, then the downloaded file is correct;
if the md5 value is not the same, the downloaded file is not correct, the downloaded file is incomplete, and it may be in the process of network download An error has occurred or the file has been modified by someone else.
Therefore, it is recommended to send the md5 value to the other party when using email to transfer files.