MD5 (message-digest Algorithm)
Converts data into a string of 32 characters.
One-way cryptographic function that accepts a message of any length as input and returns as output a fixed-length digest value to be used for authenticating the original message.
Cryptographic protocol used for authenticating messages as well as content verification and digital signature.
MD5 runs entire files through a mathematical hashing algorithm to generate a signature that can be matched with an original file. That way, a received file can be authenticated as matching the original file that was sent, ensuring that the right files get where they need to go.
The word “frog” always generates: 938c2cc0dcc05f2b68c4287040cfcf71
Similarly, a file of 1.2 GB also generates a hash with the same number of characters.
If you change just one bit in a file, no matter how large the file is, the hash output will be completely and irreversibly changed. Nothing less than an exact copy will pass the MD5 test.
MD5 is primarily used to authenticate files.
It’s much easier to use the MD5 hash to check a copy of a file against an original than to check bit by bit to see if the two copies match.
MD5 was once used for data security and encryption, but these days its primary use is authentication.
Because a hacker can create a file that has the exact same hash as an entirely different file, MD5 is not secure in the event that someone tampers with a file.
But if you’re simply copying a file from one place to another, MD5 will do the job.