What is Argon2?
Argon2 is a password hashing algorithm designed to make offline password cracking expensive. It combines repeated computation with a configurable memory cost, so attackers need both time and memory for every password guess.
Why Argon2id is usually the default:
- It balances resistance to side-channel attacks and GPU cracking better than using Argon2i or Argon2d for most password storage systems
- The encoded output stores the algorithm, version, memory, iteration, parallelism, salt, and hash in one portable string
- A unique random salt prevents identical passwords from producing identical stored hashes
- Memory and iteration settings can be increased as your verification environment gets faster
How to use this tool:
- Enter the password you want to hash.
- Keep the generated salt or create a new random salt.
- Choose the Argon2 variant and tune memory, iterations, parallelism, and hash length for the system that will verify the hash.
- Generate the encoded hash and store that full string in your application database.
Security notes:
- Do not store or log the plain password.
- Use a new random salt for every password.
- Use the optional secret only if your verifier also has that same secret; otherwise the hash cannot be verified later.
- Prefer the highest memory and iteration settings that keep sign-in latency acceptable for real users.