Hashing is not a new concept. It has been in practical use for quite a long time. To understand hashing, think about fingerprints. Every person has a unique fingerprint. Similarly, each string can have a unique fixed-size “digital fingerprint” called a hash. For a good hashing algorithm, it’s very rare that two different strings will have same hash (called a collision).
The most important feature of hashes is that the hash generation process is one way. The one way property indicates that it’s impossible to recover the original text from its hash. Therefore password hashing perfectly suits our need for secure password storage. Instead of storing a password in plain text, we can hash the password and store the resulting hash. If an attacker later gains access to the database, he can’t recover original password from the hash.
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