Argon2 & Scrypt Password Hash Simulator
Simulate and inspect modern memory-hard password hashes (Argon2 / Scrypt).
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This tool simulates and inspects modern memory-hard password hashing with Argon2 and Scrypt, giving you a hands-on look at how these algorithms structure their output and parameters directly in your browser. Argon2 won the Password Hashing Competition in 2015 and is now the recommended algorithm by OWASP for new systems, while Scrypt was an earlier memory-hard design still used in some cryptocurrency and legacy systems — both deliberately consume significant memory alongside CPU time, which makes large-scale parallel cracking on GPUs or ASICs dramatically more expensive than with simple hashes like SHA-256. Security engineers evaluating parameter choices, developers learning how Argon2's memory/time/parallelism costs interact, and students comparing password-hashing algorithms will find this simulator useful for exploring the format and behavior. All computation happens locally in your browser — no password or hash you enter is ever transmitted to a server. There's no signup and results generate instantly. For actual production password storage, always use a maintained, audited Argon2 or bcrypt library on your server rather than a browser-based demo. Scroll down to try it now.
Features
- Simulates Argon2id-style memory-hard hash output and encoded format
- Simulates Scrypt hash structure with configurable cost parameters
- Adjustable memory cost, time cost, and parallelism parameters
- Fully client-side computation, no password transmitted anywhere
- Displays the standard encoded hash string format
- One-click copy to clipboard
- Educational breakdown of how each parameter affects cracking cost
- Instant results with no signup required
Why use this password hash simulator (argon2 / scrypt)?
- Fast feedback for exploring hashing parameters
- Fully private — passwords never leave your browser
- Clear illustration of memory-hard hashing concepts
- Useful for both learning and pre-implementation testing
- Free with unlimited use and no account needed
Frequently asked questions
Is Argon2 the best algorithm for password hashing?
Yes, Argon2 (specifically Argon2id) is the current OWASP-recommended choice for new systems due to its resistance to both GPU/ASIC cracking and side-channel attacks.
What does 'memory-hard' mean?
A memory-hard algorithm requires a significant amount of RAM to compute, which makes it much more expensive to parallelize on specialized cracking hardware like GPUs and ASICs compared to CPU-only hashes.
Is Scrypt still a good choice?
Scrypt remains reasonably secure and is still used in some systems (notably certain cryptocurrencies), but Argon2 generally offers better tunability and resistance to modern attacks.
Should I use SHA-256 to hash passwords instead of Argon2?
No. SHA-256 is fast and not memory-hard, making it far easier to brute-force at scale; Argon2, bcrypt, or scrypt are purpose-built for password storage.
What are the three main Argon2 parameters?
Memory cost (how much RAM is used), time cost (number of iterations), and parallelism (number of threads), all tunable to balance security against server performance.
Does this tool produce real Argon2 hashes I can use in production?
It's designed as a simulation and educational tool to illustrate the format and behavior; for production password storage, use a maintained server-side Argon2 library.
What's the difference between Argon2i, Argon2d, and Argon2id?
Argon2d is optimized against GPU attacks but vulnerable to side-channel attacks, Argon2i resists side-channels but is weaker against GPUs, and Argon2id is a hybrid recommended for most password-hashing use cases.