What is Hashing?- A Comprehensive Guide

Hashing refers to the process of converting any given string of characters or keys into a fixed-size bit string value called a hash. It consists of a hexadecimal string of various characters.

A file consists of data blocks. Hashing algorithm transforms this data into a much shorter fixed-size value that represents the original string. A new code then replaces the information by using a hash-function.

A good hash function always has a one-way hashing algorithm means that it is impossible to convert hash back into the original key. This property is called the avalanche effect, in which when the single bit of data within the file is altered, the resulting hash changes significantly or completely. A good hash function with a high degree of randomization would not be easy to break by hackers.

If two separate inputs result in the same hash value, it makes a collision. However, good hashing algorithms have a high degree of complexity and randomization, making them less likely to have a collision.

Furthermore, to add uniqueness to the encrypted output, the random data can be added to the input of the hash function. This technique goes by the name “Salting”. For example, hackers can guess a user’s password using various techniques. Some users might have the same passwords. And in this case, it might lead to the hacking of all those accounts. Salting with random characters and digits in the hash associated with the password makes those ones unique preventing access to the same passwords.

Components of Hashing:

Key

A key is an integer or a string that is an input in the hash function.

Hash function:

It is a mathematical algorithm that creates a mapping between the input key and the resultant value or hash. Hash function input gets the input key and returns the index of an element in the hash table. 

Hash Table:

It stores all value pairs in the form of a list. Each element in it can be easily accessible through its index.

Applications:

• Hashing is widely used in hash tables to implement things like phonebooks and dictionaries. 
• The usage of hash tables makes data accessible in a very efficient manner.
• Hashing is widely used in cyber security. As the data is in the form of hashed strings, it can’t be hacked easily. If a hacker breaches into a database and finds a hash value like “a68b2,” that information is completely useless to him. 
• Moreover, hashing is also used in data encryption. Passwords are stored in the form of hashes so that if a database is hacked, passwords can’t be accessed.
• Hashing results in rapid database retrieval by shrinking these original input data into short alphanumeric hash keys, which also saves file space. 
• Hashing is also used to help encrypt and decrypt digital signatures. When a digital document is digitally signed by a signer using his private key, a hash is created, matching the data in the document. Then data is encrypted and appended with a hash. This data is then sent along with public keys to the recipient. The recipients decrypt the data using the public key. Another hash is created there, and both hashes are compared to check the authenticity and integrity of the signed document.

In short, hashing is a useful and popular tool to ensure the integrity and security of data files.