Difference between Confusion and Diffusion in Cryptography

Confusion and diffusion are both properties for creating a secure cipher. Confusion and diffusion are both used to prevent the encryption key from its deduction or to prevent the original message from being transmitted. Confusion is utilized to create clueless ciphertext, whereas diffusion is utilized to increase the redundancy of the plaintext over most of the ciphertext to make it obscure. The stream cipher relies solely on confusion. On the other hand, diffusion is also utilized both stream and block ciphers.

In this article, you will learn about the difference between Confusion and Diffusion. But before discussing the differences, you must know about Confusion and Diffusion.

What is Confusion?

Confusion is a cryptographic mechanism that is utilized to increase the obscurity of the ciphertext. In simple words, the technique assures that the ciphertext has no information about the plaintext. The confusion technique keeps the relationship between the encrypted text's statistics and the encryption key's value as complex as possible. Even if the attacker gains some control over the ciphertext's statistics, he will be unable to determine the secret because the method by which the key was utilized to generate the ciphertext is so complex. Confusion may be created by employing substitution and a complicated scrambling algorithm that is dependent on the key and the input (plaintext).

What is Diffusion?

Diffusion may be used to define the property that the repetition in the plaintext statistics "dissipates" in the ciphertext statistics. In diffusion, the output bits must be challengingly dependent on the input bits so that if the plaintext is modified by only one bit, the ciphertext must change in an unanticipated or unreliable way.

The statistical technique of the plaintext is utilized up into high-range data of the ciphertext during diffusion. It is achieved by influencing the value of some ciphertext digits with each plaintext digit, and it is frequently similar to having certain plaintext digits impact each ciphertext digit.

Key Differences between the Confusion and Diffusion

There are various key differences between Confusion and Diffusion. Some main differences between Confusion and Diffusion are as follows:

1. Confusion is a cryptography technique used to generate the vague ciphertext. On the other hand, diffusion is employed to create cryptic plain texts.
2. The diffusion attempts to make the statistical relationship between ciphertext and plaintext as complex as feasible. In contrast, the confusion strategy attempts to make the association between ciphertext statistics and encryption key value as complex as possible.
3. The confusion technique is achieved via the substitution technique. On the other hand, diffusion may be achieved via the use of transposition techniques.
4. If a single bit in the key is modified, most or all bits in the ciphertext will be modified in confusion. In contrast, if a single character in the plaintext is modified, almost symbols in the ciphertext are also changed in diffusion.
5. The confusion technique conceals the relationship between the key and the ciphertext. On the other hand, diffusion conceals the relationship between the plaintext and the ciphertext.
6. The confusion technique utilizes both stream and block cipher. In contrast, the diffusion technique utilizes only block cipher.
7. A one-time pad is completely based on confusion, and a substitution cipher is another instance of a confusion-only cryptosystem. On the other hand, a double transposition is the common instance of a diffusion-only cryptosystem.

Head-to-head comparison between Confusion and Diffusion

Here, you will learn the head-to-head comparisons between Confusion and Diffusion. The main differences between Confusion and Diffusion are as follows:

Conclusion

Confusion and diffusion are both cryptographic approaches. In confusion, the relationship between the ciphertext's statistics and the encryption key's value is as difficult as possible. On the other hand, diffusion attempts to disguise the statistical nature of the plaintext by spreading the influence of each individual plaintext digit over a large number of ciphertext digits.