Many computer users over time, with a more detailed acquaintance, ask about hash sums. They are also called checksums. What is it? What is it for? How are these amounts calculated?
Definition
A checksum is a specific value that is calculated for data using special algorithms. The purpose of the hash is to verify the integrity of the data during transmission. The most common calculation algorithms are MD5, CRC32, and SHA-1. Checksums can also be used to compare data sets for nonequivalence, which is useful for detecting viruses on a computer.
The use of this method has gained popularity due to the fact that verification is easily implemented in digital equipment that works with a binary number system. It is analyzed without problems and is great for finding errors that are caused by the presence of noise in information channels.
Algorithms for checking
The MD5 algorithm is used not only to check the integrity of data, but also makes it possible to obtain a sufficiently reliable identifier, which is often used when identical files are searched on the computer. Thus, it does not compare the contents, but their hash sums.
The CRC32 algorithm is used in the work of archiving programs. It stands for “cyclic redundancy code”.
The SHA-1 algorithm is used to verify the integrity of data that is downloaded using the BitTorrent program.
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 in order and nothing is lost during the transfer. The easiest way to do this is to compare the hash of the downloaded file and that provided by the author. If they completely match, then the image does not contain errors. Well, if the hash amounts of the files are different, you need to re-download, as there was some kind of failure.
This elementary procedure serves as a preventive measure against incorrect operation, freezes. Performing it, you can be sure that the installation of the operating system, program or game will be correct.
Next, utilities that do a great job of calculating and checking data checksums will be described.
HashTab: hash verification
This utility is a plugin that integrates into the operating system and is used when needed. It can be downloaded from the official site for free as an installation file. Installing the program is intuitive.
After installation, the properties of each file will have 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 amounts? To do this, in the "Comparison" field, you need to insert the amount specified by the author. If the downloaded file has successfully passed authentication, a green checkmark will appear. Otherwise, the user will see a red cross. In this case, it is recommended to download the file again.
The settings on the “Hash file sums” tab can be changed by clicking on the corresponding item. The parameters window opens, where it is possible to set the display of the necessary checksums for verification and calculation. In order to make everything visual, it is recommended to tick off the checkbox, which allows you to display checksums with lowercase characters.
Thus, working with this program is very simple. Even an inexperienced user can figure it out.
MD5 File Checker
This utility is also downloaded from the official site, but it does not require installation. You just need to run it. She uses the algorithm of the same name to check. When downloading a file, you need to 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 said whether the checksum of the files matches or the file is damaged and there is no match.
An additional feature of the utility is the calculation of the amount according to the MD5 algorithm for any file on the computer.
Conclusion
So, the concept of “checksum” was considered. It became clear what it was used for. For the average user, this is an easy option to check the file for integrity and compliance 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 only according to one algorithm, but it does not require installation, which is important in the absence of administrator rights.
If you intend to install an operating system or any other software product, it is recommended that you verify the hash amounts after downloading all the installation files. This will save a lot of time and, more importantly, nerves.