Hashing is a process that transforms input data of any size into a fixed-size string of characters, typically a sequence of numbers and letters. This output, known as a hash value or hash code, serves as a unique identifier for the original data. Hashing is commonly used in computer science for data integrity, ensuring that even a small change in the input will produce a significantly different hash value. One of the main applications of hashing is in cryptography, where it helps secure sensitive information like passwords. When a password is hashed, the original password is not stored, making it difficult for unauthorized users to retrieve it. Popular hashing algorithms include SHA-256 and MD5, each with its own strengths and weaknesses in terms of security and speed.