What is the term for changing a single bit of plaintext that affects all bits of the resulting ciphertext?

The correct term for the phenomenon where changing a single bit of plaintext affects all bits of the resulting ciphertext is known as Complete Avalanche. This concept is rooted in the design of cryptographic algorithms, particularly block ciphers. When a minor alteration in the plaintext leads to a significantly different ciphertext, it ensures a high level of security by maximizing unpredictability in the output.

Complete Avalanche is specifically important in ensuring that even slight changes in input produce drastic changes in output, thereby complicating any attempts at cryptanalysis. This characteristic is a crucial aspect of robust encryption algorithms, which aim to prevent attackers from deducing relationships between the plaintext and ciphertext.

In comparison, diffusion refers to the property of spreading out the influence of the plaintext over the ciphertext. Clustering typically refers to the concept where data points are grouped together in analysis contexts, not specifically relevant to encryption. Confusion relates to obscuring the relationship between the plaintext and ciphertext, but does not specifically address how a single bit change can impact the entirety of the ciphertext.