How do hashing and encryption methods differ, and in what cases are they used?

Hashing and encryption methods serve different purposes and work differently:

• Hashing is the process of transforming data into a fixed-length string (hash) that uniquely represents the original data. Hash functions are irreversible, meaning the original data cannot be recovered from the hash. It is used for data integrity verification, password storage (with salt), quick search, and comparison.

• Encryption is the process of converting data into an encrypted form using a key to hide its content. Encryption is reversible: with the key, the data can be decrypted to obtain the original text. It is used to protect confidential information during transmission and storage.

Example:

• Password hashing: during registration, the password is hashed and stored; during login, the entered password is hashed and compared with the stored hash.
• Message encryption: the message is encrypted before sending, and the recipient decrypts it using the key.

Thus, hashing is for verification and identification, encryption is for protection and confidentiality.