What Happens When a Password Gets Hashed? Security Explained

Slack: In 2022, The Register reported that Slack exposed hashed passwords for years. While the passwords were hashed, the exposure of the hashes meant that users had to reset their credentials to ensure their accounts remained secure.
Plex: Similarly, Plex admitted to a breach involving account details, including hashed passwords. This incident underscores that even major platforms are targets for cybercriminals.
MyHeritage: In a massive breach reported by Bitdefender, 92 million emails and hashed passwords were leaked. The exposure of these hashes forces millions of users to question the security of their long-standing accounts.

2026-05-28

When you create an account on a website or app, the service provider collects your password. You might assume this password is stored exactly as you typed it—perhaps even encrypted. However, this is a critical security misconception. In the world of cybersecurity, hashing is the standard method for storing credentials. But what actually happens when a password gets hashed, and why is it so vital for your digital safety?

The Fundamental Concept: One-Way Encryption

At its core, hashing is a mathematical process that converts an input (like your password) into a fixed-size string of characters, known as a hash value or hash.

Unlike encryption, which is a two-way process (you can encrypt data and then decrypt it back to its original form using a key), hashing is one-way. Once a password is hashed, it is mathematically impossible to reverse-engineer the original password from the hash value alone.

The Transformation Process

Imagine you have a password: "SuperSecret2024!".

When you log in, the server takes this string and runs it through a hashing algorithm. The result might look like this: