What is produced by hashing to ensure data integrity?

Hashing is a process used to convert input data into a fixed-size string of characters, which is typically a sequence of numbers and letters. This fixed-size output, known as a message digest, serves a critical role in ensuring data integrity. When data is hashed, any slight change to the original input data will result in a completely different message digest. Thus, comparing the message digest of the original data with a newly computed digest of the received data can reveal whether the data has been altered or remains intact.

By utilizing message digests, systems can verify the integrity of data during storage or transmission. If the message digests match, it indicates that the data has not been tampered with; if they differ, it signals an issue that needs attention. This property of hashing makes it essential for various applications, including digital signatures and data verification processes, where data integrity is paramount.

The other options—encryption key, digital signature, and hash algorithm—do not directly represent the output of the hashing process responsible for ensuring data integrity. While they are related to security and data protection, they serve different functions in the realm of cryptography and data security.