Hashing is a process used to convert input data of any size into a fixed-size value, called a hash or hash code, using a mathematical function known as a hash function. It is commonly used in computer science and information security for various purposes, including:
Data Storage and Retrieval: Hashing is used in hash tables to quickly store and retrieve data based on a key. The hash function maps keys to specific locations in the table, enabling fast lookups.
Data Integrity: Hashing ensures data integrity by generating a hash value for a file or message. If the data is altered, the hash value changes, making it easy to detect tampering.
Password Storage: Hash functions are used to securely store passwords. Instead of saving the password itself, systems save its hash, making it harder for attackers to retrieve the original password.
Digital Signatures and Cryptography: Hashing is a critical component in cryptographic algorithms, ensuring secure communication and authentication.
An ideal hash function produces unique hash values for different inputs, distributes values uniformly, and is computationally efficient. Popular hash functions include MD5, SHA-256, and CRC32.