What is the link between hash functions and data integrity?

Hash functions play a critical role in maintaining data integrity by generating a unique hash value, or "fingerprint," for a specific set of data. When data is transmitted or stored, the hash function computes a hash value based on the contents of that data. If the data is altered in any way, even a single bit, the hash value will change significantly. This property allows for easy verification of data integrity; by recomputing the hash value after the data is received or accessed, one can compare it against the original hash value. If the values match, it indicates that the data has remained unchanged, affirming its integrity.

In this context, options that focus on encryption standards or file size alterations do not accurately reflect the primary purpose of hash functions, which is to ensure that the original data remains intact and unmodified. The role of hash functions is not oriented toward speeding up file recovery, nor do they inherently nullify changes in file sizes, making the chosen answer the most relevant and accurate in explaining the connection between hash functions and data integrity.