What is the purpose of salting in hashing data?

Salting in hashing data is primarily used to ensure that identical inputs produce different hash values. This is achieved by adding a unique, random string of characters (the salt) to the input data before it is processed by the hash function. As a result, even if two identical pieces of data are hashed, the inclusion of different salts will lead to different hash outputs. This technique is crucial in preventing attacks such as rainbow table attacks, where an attacker could precompute hash values for common passwords and look them up in a table. By salting the data, each hash is unique to the specific combination of data and salt, significantly increasing security.

The other options address characteristics not directly related to the core purpose of salting. Salting does not inherently improve the speed of hash functions or create a secondary encryption layer, nor does it increase the size of the hashed output. Instead, salting introduces randomness which adds complexity to the hashing process but focuses on thwarting specific vulnerabilities related to identical data producing the same hash.