HASHING FILE WITH MD5 HASH AND HOW TO USE IT?

MD5 HASH This program is used to compute and check message digest MD5 (Message Digest Algorithm 5). md5sum hash function is often used in cryptography and computer forensics to check the integrity of the file. MD5 is an Internet standard (RFC 1321). In addition to using the md5sum hashing can also use the sha1sum, sha224sum, sha256sum, sha384sum, sha512sum. While for the sum and cksum can only be used to view the file size in bytes. 

At this session I will try to check the two files in one folder, and then one file editing is done by removing the space between two words. First step will create two file.

Create different file and save with the name testfile1 and testfile2:

testfile1

testfile2

Next, lets use md5sum to hashing this file.

Hashing md5sum

In the picture above there are two types use the md5sum :

• The first md5sum check on all files located in folder hashing.

• The second with the md5sum check on each files

The results of the two files above hashing is an md5 hash of the first column of size 32 character hexadecimal.  To prove that the md5sum to check the validity and integrity of a file then I will do the editing in one file (testfile2) by deleting the existing space between two words. In th

Editing testfile2

Further to check the validity of all existing files in the folder hashing.

md5sum validity

The result is testfile1 OK its means this file valid (the file unedited), and the second file with the name testfile2 is Failed its means this file is already modification or edited by someone so the checksums of testfile2 after and before editing did not match. Check with each files.

md5 hash testfile2 after edited

md5 hash testfile2 before edited

Look this hexadecimals before file edited and after file edited did not match !.