What is a checksum and why is it important in information security?
Who hasn’t had a corrupted file before? During transfer and download processes, it’s quite common for malicious interferences to compromise data integrity, posing a risk to a company's operations. In this context, a checksum serves as a verification tool to check whether data has been tampered with or not.
Want to know more about checksums and how they work? Continue reading this article to learn more!
What is a checksum?
Checksum is a technique used to verify data integrity during transmission or storage. It acts like a digital signature, helping to confirm whether files remain intact and have not been improperly modified.
It's important to note that the checksum is calculated at two points: at the source, before transmission or storage, and at the destination, after data reception or retrieval. A comparison between the two checksum values then takes place, allowing verification of whether the received data is the same as the originally sent or stored data.
How does a checksum work?
The checksum process is relatively simple and can be broken down into a few basic steps. Here’s an overview of how it works:
1. Calculating the checksum at the source
In the first step, data is selected, and a checksum algorithm is chosen to compute the compact value of the file. The result is a checksum value, which is significantly smaller than the original data.
2. Transmission or storage
The data and its checksum value are then transmitted to the recipient or stored together.
3. Verifying the checksum at the destination
After receiving the data, the same checksum algorithm is applied to generate a new value based on the received data. The source and destination checksum values are then compared.
4. Verification result
The comparison reveals whether the data has been corrupted. If the values match, the data has not been altered and remains intact. If they don’t match, it indicates that the data may have been changed or corrupted.
How to generate a checksum?
Generating a checksum is a technical process that involves applying a specific algorithm to the data. Here's a basic step-by-step guide to creating one:
1. Choose a checksum algorithm
There are several algorithms available, such as MD5, SHA-1, SHA-256, among others, each with its own characteristics and security levels.
2. Select the data
Determine which data you want to calculate the checksum for, such as a file, a text message, or any set of data and information to be shared.
3. Use a tool or library
You can use a command-line tool or a programming library that implements the chosen checksum algorithm. For example, in Unix/Linux systems, you can use the md5sum or sha256sum command. In programming languages like Python, libraries are available for checksum calculation.
4. Perform the checksum calculation
Use the selected tool or library to calculate the checksum for your data. This typically involves running a specific command or function, passing the data as input.
Why is checksum important for information security?
Checksums are a good security practice because they allow verification of data integrity during transmission, storage, and processing. By generating a checksum for a data set, it becomes possible to detect any accidental or intentional changes to the data.
In a context of high cyber threats, this is essential to ensure that information has not been corrupted, manipulated, or compromised in any way.
This helps guarantee the reliability and accuracy of data, especially in environments where data integrity is critical, such as in security systems, financial transactions, file transfers, and more.
Did you enjoy this content? You can access more articles about cybersecurity techniques on the BugHunt Blog. Click here to explore our feed.