Can you explain how hash algorithms work? How do they prevent collisions (2 pieces of data having the same hash)? and where should they be used?
A Hash function is an algorithm that takes a input, called a "key," and returns another value, also called a "hash code." A hash function uses mathematical operations to transform the key into a unique number. This number is then used as a checksum or identifier for the data being hashed.

To prevent collisions, most hash functions use a technique known as "iterative hashing." In this approach, the hash function repeatedly applies its transformation process to the key until it produces a final result. If two keys have the same final hash code, it means that they have the same original key and therefore are considered to be colliding. To resolve these conflicts, some hash functions may simply repeat the transformation process with different inputs, while others may use a combination of techniques such as salt padding, collision resistant encoding, or error correction codes to ensure that no two keys produce the same hash code.

Hash algorithms are often used in computer science, cryptography, and information security applications because they provide a way to quickly check if a particular piece of data is in a database or if it corresponds to a specific location on a disk. For example, when creating an encryption scheme, a hash function can be used to encrypt the message using a unique key, ensuring that only the intended recipient can decrypt it. Similarly, in digital signature algorithms, a hash function can be used to create a unique "signature" for each piece of data, which serves as proof that it was created by a specific sender.

Overall, the goal of a hash function is to map complex objects to simple numbers in a manner that is both efficient and unpredictable. By utilizing hash functions, we can reduce the time and resources required to locate specific data in large databases and protect sensitive information from unauthorized access.