Through the Internet we can have access to all types of programs and documents and, depending on where we download it from, there is a method that allows us to know if it is the original program that the creator has compiled or if it is a modified version, which It represents a danger to the security of our PC.
Just as we can know if we are downloading the file as compiled by the developer, we can also know if, once we share a file, it has been modified, even if only to remove or add a period.
To know this information, it is necessary to know what its fingerprint is, a fingerprint that allows us to identify the content of a file using a sequence of characters. This is known as hashing. To calculate the hash of a program or file (photo, document, video, among others), we only have to apply a mathematical function, which is responsible for analyzing the file/program to create a numerical sequence.
What is a hash and what is it for?
The hash is a fingerprint of the invariance of a program or file. The developer of an application or ourselves can create a hash of the file that we are going to share on the Internet or with other people so that anyone who downloads that file can verify that it is the original file and that it has not been modified by anyone else. person.
If, for example, we share a Word file with other people, before doing so, we can create a hash of it to check, when it is returned to us, if it has been modified at any time, even if it is a comma, a period or a word . When a hash is created, we can use different algorithms (MD5, SHA-1, SHA-256 among others) the file is analyzed and a certain number of mathematical operations are performed that analyze its content, the size of the file and show us a sequence of numbers and letters.
We can calculate the hash of the same file as many times as we want, since we will always obtain the same sequence of numbers and letters, as long as we do not modify it. In this way, continuing with the example, if we share a large Word file, of which we know the hash before sharing it, if, upon receiving it, we recalculate it and we do not have the same number, it means that it has been modified.
This same case can be applied to a video file, a photograph, an Excel sheet or any other type of file, no matter the extension and format. This information is especially useful when we want to download a program and we want to make sure that it is a version that has really been complicated by the developer and not by third parties who have put it into circulation with, probably, bad intentions.
To find out what the hash of a program is, we just have to visit its website, although, unfortunately, not all of them offer this information. In the case of Windows, no need to check what the hash is As with Adobe tools, since their respective websites are the only places from which we must download the applications. As long as we download the software from the developer’s original website, it will not be necessary to check it.
How to check and create the hash of a file
To create and/or check a hash, you must apply a mathematical function, a function that we can apply using one of the applications that we show you below.
- QuickHasth GUI. QuickHash GUI is one of the most complete applications to know and create the hash of any file since it allows us to export this information in .html or .csv format to store it. In addition, it also shows us information about the content of the file such as the number of files, total space, path and much more. This application is available for Windows, Linux and macOS through this link.
- OpenHashTab. OpenHasthTab is an open source application that allows us to check the signature of any file without leaving the file explorer. In addition, it allows us to paste the signature we have to know that information instantly. We can also use the application to create the hash of any file. We can download the application from here.