Many of us use Linux Distributions like Ubuntu, Fedora, available for free on the Internet. To install these distributions on our computers, we need to down their ISO files. Recently, the Linux Mint ISO was hacked and malware inserted into some of it’s files. It was then repacked and put up on an external website. Only an alert and savvy user would have been able to identify that the ISO being offered from download was from another site. Also, to verify that the ISO was genuine, would mean that you would need to know how to calculate the checksums / hashes using MD5 or SHA256.
MD5/SHA256 generate unique fingerprints for each file they are used upon. Later, these fingerprints can be matched to identify that the files that were downloaded were not manipulated, incomplete while they were being transmitted. Basically, an MD5 or SHA256 signature verification assures the integrity of the file downloaded.
To find out the MD5 sum of a file in Linux, open a terminal window and enter the following command:
$ md5sum <filename> <enter>
where <filename> is the name of the file for which you want to calculate the MD5 sum.
To find out the SHA256 sum of a file in Linux, open a terminal window and enter the following command:
$ sha256sum <filename> <enter>
where <filename> is the name of the file for which you want to calculate the SHA256 sum.
If you want to find out the MD5 or SHA256 sum for a file on an Android device, download Jackpal’s Terminal Emulator, start it and enter the same commands as above to find the checksum. After all, the base of Android is Linux.