In what cases are hashing methods used for data processing?

Hashing methods are used to transform data of arbitrary size into a fixed size — a hash.

Main use cases:

• Data integrity verification: for example, checksums to detect changes.
• Password storage: passwords are stored as hashes for security.
• Fast search and comparison: in data structures such as hash tables.
• Digital signatures and cryptography: to create unique data fingerprints.

Example in Java:

MessageDigest md = MessageDigest.getInstance("SHA-256");
byte[] hash = md.digest(inputData.getBytes(StandardCharsets.UTF_8));

Here, inputData is transformed into a fixed-length hash, which can be used for comparison or verification.