What is a Checksum?

A checksum is a mathematical algorithm that generates a unique value based on a set of data being transmitted. This value is then used to verify the authenticity of the data and ensure that it has not been corrupted during transmission, providing an added layer of protection.
In the following, we will delve deeper into the concept of checksum, and how a single period can make a huge difference.

How does a checksum work?

A checksum or hash sum works by creating a unique value from the data being transmitted. This value is calculated using a specific algorithm, and it is attached to the data set being transmitted. The receiver of the data packet can then perform the same calculation and compare the generated checksum value with the attached value. If the two values match, it is assumed that the data was transmitted without any errors. If the values do not match, the data set is considered to be corrupt, and it must be retransmitted.

Checksum examples

Although checksums seem tricky to understand, we’d like to prove to you that they are, in fact, not hard to understand at all. Let’s generate a hash sum from text using the MD5 checksum:

Scanbot is pretty great.


Now, let’s remove just the period. You will see that the 128-bit code has completely changed:

Scanbot is pretty great


Checksums are widely used in the transmission of files, especially over the internet. In this case, the sender might generate a checksum value for the file being transmitted and includes it with the file. The receiver then generates a checksum value for the downloaded file and compares it with the original checksum value to ensure that the file was downloaded error-free.

Checksum benefits

Checksums are a simple and effective way to ensure the integrity of digital data. By providing an added layer of protection against data corruption, checksums can help to improve the security and reliability of digital systems. However, they do not provide any error correction.

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