How do you do authentication with message digest(MD5)?

MD5 is a cryptographic hash function with a 128-bit hash value output. It is used to check the integrity of input. It takes the variable-length input and converts it into a fixed length output of 128-bits called as MD5 hash. Any change in the message would result in a completely different hash. Hence, the message (input/password etc.) would fail the authentication process if they are incorrect or altered in any way.