In today's world, we use internet and communication technologies daily for both personal and professional purposes. We send emails and files, chat with friends and colleagues, share content on social networks, make purchases, and much more. As a result, we send and receive a significant amount of sensitive data every day. Our devices, the platforms we use, email servers, messaging software, and browsers employ various encryption techniques to ensure secure communication.
Encryption aims to transform information from a readable and coherent state into an unintelligible one. This way, even if someone manages to acquire the message, they cannot understand it.
A wide range of algorithms is used for encryption, and XOR is one of them. In this article, we will explain in detail what XOR is and discuss the reasons why XOR is important in cryptography.
What is XOR encryption?
In simple terms, XOR encryption (pronounced 'exclusive or') is an additive encryption. It is based on the XOR operation (also called exclusive disjunction) in logic.
As a logical operation, XOR is also referred to as addition modulo 2. In the XOR operation, the output is true when the inputs differ. In other words, the XOR operation means 'either one, but not both, or none'.
Below, you will find the principles of XOR (⩛ represents the XOR operation):
A ⩛ 0 = A
A ⩛ A = 0
( A ⩛ B ) ⩛ C = A ⩛ (B ⩛ C)
( B ⩛ A ) ⩛ A = B ⩛ 0 = B
XOR encryption uses the XOR logical operation to encrypt data. First, a random key is generated. Then, the XOR operation is performed using the key to create encrypted data. To decrypt, the same key must be used, and the XOR operation must be executed again.
The XOR operation uses the same key for both encryption and decryption. That's why it's called symmetric encryption. This means that the same key is used to encrypt and decrypt data, which simplifies the encryption and decryption process.
Why is XOR encryption important?
XOR encryption is known for its strong resistance to brute-force attacks, where an attacker generates random keys and tries them until the correct key is found.
Furthermore, XOR implementation is very straightforward. That's why XOR is used inside most encryption algorithms or in conjunction with various other encryption methods. However, the most significant feature of XOR encryption is that it can be 'perfect cipher' with a one-time pad.
The one-time pad refers to an encryption technique where the key is:
- Truly random,
- Kept secret,
- As long (or longer) than the plaintext,
- Never reused in whole or in part.
When XOR encryption uses a truly random key of the same length as the message itself, it becomes unbreakable. In other words, it provides the highest level of security.