Checking the hash sums: what is it?

Many computer users over time, with a more detailed acquaintance, are wondering about the hash sums. They are also called checksums. What is it? What is it for? How are these very amounts calculated?

Definition

A checksum is a specific value that is calculated for data using special algorithms. The purpose of hash sums is to check the integrity of the data when it is transmitted. The most common algorithms for calculation are MD5, CRC32 and SHA-1. Checksums can also be used to compare datasets to nonequivalence, which is useful for detecting viruses on a computer.

The popularity of the use of this method is due to the fact that verification is easily implemented in digital equipment working with the binary system of calculus. It is analyzed without any problems and is great for finding errors that are caused by the presence of noise in information channels.

Algorithms for verification

The MD5 algorithm is used not only to check the integrity of the data, but also provides a reliable enough identifier, which is often used in cases where the same files are found on the computer. Thus, there is a comparison not of the content, but of their hash-sums.

The CRC32 algorithm is used in archiving programs. It stands for "cyclic redundant code".

The SHA-1 algorithm found application when checking the integrity of data that is loaded using BitTorrent.

Example

For example, a user wants to install an operating system or game on his computer. He downloads the image and wants to make sure that the integrity of the file is OK and nothing is lost during the transfer. The easiest way to do this is to compare the hash sums of the downloaded file and the one provided by the author. If they completely match, then the image does not contain errors. Well, if the hash-sums of the files differ, you need to re-download, because there was some kind of failure.

This elementary procedure serves as a preventive measure against incorrect work, hang-ups. By executing it, you can be sure that the installation of the operating system, program or game will be correct.

Next, you will find utilities that are good at calculating and verifying checksums.

HashTab program: checks the hash sum

This utility is a plug-in that integrates into the operating system and is used at times of need. It can be downloaded from the official site for free in the form of an installation file. The installation of the program is intuitive.

After installation, in the properties of each file there will be a new additional tab for calculating the checksum. By default, they will be calculated using the same three algorithms described above.

How to check hash sums? To do this, in the field "Comparison" you need to insert the amount, which is indicated by the author. If the downloaded file has successfully passed the authentication check, a green checkmark will appear. Otherwise, the user will see a red X. In this case, it is recommended to download the file again.

Settings on the "Hash-sums of files" tab can be changed if you click on the corresponding item. A window of parameters opens where it is possible to display the necessary checksums for verification and calculation. In order for everything to be clear, it is recommended to check the checkbox, which allows to show checksums in small characters.

Thus, working with this program is very simple. Even an inexperienced user can understand it.

MD5 File Checker

This utility is also downloaded from the official site, but it does not require installation. You just need to start it. It uses an algorithm of the same name for verification. When downloading a file, copy the hash of the original to the clipboard, and then paste it into the field for verification. The next step is to select the file that the user wants to test for integrity. After clicking on the "Check" button, a message will be received with the result of the work, where it will be told whether the checksum of the files is corrupted or the file is corrupted and there is no correspondence.

An additional feature of the utility is the calculation of the amount by the MD5 algorithm for any file on the computer.

Conclusion

So, the concept of a "checksum" was considered. It became clear why it was used. For an ordinary user, this is an easy option to check the file for consistency and consistency with the original. Useful utilities for calculating and comparing hash sums have been described. The first is able to compare different amounts, and the second is only one algorithm, but it does not require installation, which is important in the absence of administrator rights.

If you are going to install an operating system or any other software product, it is recommended to check the hash sums after downloading all the installation files. This will save a lot of time and, more importantly, nerves.