Difference Between Confusion and Diffusion

Difference Between Confusion and Diffusion in Tabular Form

Diffusion: Property of statistical distribution. So if you find the statistical property, you can find the key.

Confusion: Property of drastic change of ciphertext. Little change of key makes huge output(=Ciphertext of an Incredibly different pattern)(Usually this principle is told by hiding the relationship between ciphertext and key).

Comparison Chart

Definition of Confusion

  • Confusion each character of ciphertext depends on a different part of the key. In confusion the key does not directly related to ciphertext. It is a classical substitution cipher.

Confusion = Substitution

a —>b

Caesar cipher

  • For Example, Suppose we have a Hill cipher with a matrix n x n and suppose we have a plaintext-ciphertext pair of length n2 with which we are able to solve for the encryption matrix.  When a situation like that happens, the cryptanalyst would probably need to solve for the entire key simultaneously, rather than piece by piece.

Definition of Diffusion

  • Diffusion It means any of the characters in plaintext is changed, then simultaneously several characters of the ciphertext should also be changed. If the character of ciphertext is change then simultaneously several characters of plaintext also changed. It is a classical transposition cipher.

Diffusion = Transposition or Permutation

abcd —>dacb


  • For Example, Hill Cipher has the characteristic of diffusion.

Related Differences:

  1. Difference Between Stream Cipher and Block Cipher
  2. Difference Between Monoalphabetic Cipher and Polyalphabetic Cipher
  3. Difference Between Active and Passive Attacks
  4. Difference Between Symmetric and Asymmetric Encryption


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