What is MD5 Hash ?

 

MD5 Hash Algorithm

In this article, I will tell you about MD5 Hash algorithm.It is a very useful technique for keeping things secret and safe.However it is old but is still very useful.

 So what is this MD5?
       MD5 stands for Message Digest algorithm 5.It is widely used for security purposes and keeping things secret or hidden.It was designed be Ron Rivest in 1991 to replace MD4, another older algorithm.MD5 was an improved version of it.MD5 is a hash generating cryptographic algorithm.

How does it works?

It takes some data as input, the data may be text or binary, and then it generates a fixed length hash value.The input can be of any length but the output will always be of a fixed length.The fixed length is 32 digit hex hash.A diagram will explain it all.

As you see that it doesn't matters how long the input is the output hash will always be 32 digit in hexadecimal.
 Uses of MD5 Hash 
 The hash is very useful for security purposes.For example if you download file from the Internet, or a backup of the data you have created on a server, the file may not be the original one.It could have been tampered by viruses or some bytes might have been missed during the download.
      To check whether you have got the original file you can create the MD5 hash of the original file and save it somewhere.After a long time you would need your backup files, after downloading the files you can create MD5 hash and match it with the original files hash.If it gets matched, then the file is not broken or damaged by any means, if it doesn't the the file will be corrupted.

How to create MD5 Hash of a file?
For Windows, you can use this utility, MD5 summer.Well it works good, but I have another utility which does the job even better.The name is Hash tab.It integrates itself into the properties menu and create a tab File Hashes. It shows different Hashes with different algorithms such as CRC32, MD-5, SHA-1. So you can check the hash and write it somewhere, then make a backup of that file, and when you need it you check its hash and compare it with the original hash value, then you know that it is all good or maybe corrupted.


For Unix you can use the command, md5sum:

for example,
md5 myfiles.rar


you can replace myfiles.rar with the name of your file.


How to create MD5 HASH of text?

Well if you want to send someone a secret message you can take advantage of MD5.Just use this website to generate the MD5 hash of the text you want.Then send it to anybody you want, and then he can convert it back using any MD5 decryptor such as this one.


Nowadays MD5 is replaced by SHA-0, SHA-1 and SHA-2 and also SHA-3 algorithms.Many  algorithms such as CRC32 are also used.