What is Diffusion?

Understanding Diffusion

Provided by mixing up the location of the plaintext throughout the ciphertext. The strongest algorithms exhibit a high degree of confusion and diffusion. In cryptography, diffusion is a property where changing one bit of the plaintext results in changing multiple bits of the ciphertext, spreading the influence of input bits across the output. This makes it difficult to identify patterns or relationships between plaintext and ciphertext. Along with confusion, diffusion is fundamental to strong encryption as defined by Claude Shannon. The diffusion principle is applied in algorithms like AES through operations such as ShiftRows and MixColumns. Organizations implement diffusion by using well-designed, standardized encryption algorithms rather than creating custom solutions. For example, the AES encryption algorithm achieves diffusion through operations that spread the influence of each plaintext bit across many ciphertext bits, making statistical analysis attacks extremely difficult. Related terms: Confusion, Avalanche effect, Substitution-permutation network, Block cipher, Shannon principles, Cryptographic strength.