What is hashing?
Hashing is a cryptographic process that can be used to validate the authenticity and integrity of various types of input. It is widely used in authentication systems to avoid storing plaintext passwords in databases, but is also used to validate files, documents and other types of data. Incorrect use of hashing functions can lead to serious data breaches, but not using hashing to secure sensitive data in the first place is even worse.
Hashing versus encryption
Hashing is a one-way cryptographic function while encryption is designed to work both ways. Encryption algorithms take input and a secret key and generate a random looking output called a ciphertext. This operation is reversible. Anyone who knows or obtains the secret key can decrypt the ciphertext and read the original input.