Is bcrypt secure in 2025?

Yes, bcrypt is still considered secure when used with an appropriate cost factor. However, Argon2id is recommended for new applications.

How does bcrypt verify passwords?

Bcrypt stores the salt and cost factor inside the hash. During verification, the input password is hashed again using the same parameters and compared.

Bcrypt Hash Generator and Verifier Online

Q: What is bcrypt used for?

Bcrypt is a password hashing algorithm used to securely store passwords. It incorporates salting and an adaptive cost factor to resist brute-force attacks.

Q: What bcrypt cost factor should I use?

A cost factor between 10 and 12 is recommended for most modern systems, depending on acceptable performance overhead.

Q: Can bcrypt hashes be reversed?

No, bcrypt is a one-way hashing algorithm and hashes cannot be reversed to retrieve the original password.

Generate and verify bcrypt password hashes instantly using this free online tool. Supports configurable salt rounds (cost factor) and real-time password matching. This tool also works as a bcrypt password verifier, allowing you to match plain text passwords against existing bcrypt hashes.

Confused about whether bcrypt is still the right choice for modern applications? Read my practical comparison of Argon2 vs bcrypt vs scrypt, based on real-world implementations and security trade-offs.

Generate Bcrypt Hash

Enter plain text to hash

Select the number of Salt Rounds

Hashed Output:

Verify Bcrypt Password

Enter the Bcrypt Hashed Password

Enter the Plain Text Password

Result

We do not store or log any data you enter. This tool runs entirely server-side with no persistence. Intended for personal and educational use — avoid using online tools for real production secrets.

Key Features of Bcrypt

Salted Hashing Incorporates a random salt to protect against rainbow table attacks — same password produces different hashes every time.

Adaptive Cost Factor Configurable work factor lets you increase computation time as hardware improves, staying ahead of brute-force attacks.

Blowfish-Based Derived from the Blowfish cipher with an expensive key setup phase that adds inherent slowness.

Cross-Platform Widely supported in Java, Python, Node.js, PHP, and more. See how to implement bcrypt in Spring Security.

Recommended Rounds: 12 Cost factor 12 balances security and performance for most apps. High-security systems may use 13+, as long as login times stay acceptable.

One-Way Hash Bcrypt hashes are irreversible. Passwords are verified by re-hashing — the original value can never be recovered.

How Bcrypt Works

Salting A cryptographically random salt is generated per password. The salt is combined with the plaintext before hashing, ensuring unique output even for identical inputs.

Hashing The Blowfish cipher is applied to the salted password repeatedly, based on the cost factor. Each increment of cost doubles the computation time.

Storing The final output encodes the cost factor, salt, and hash together in a single 60-character string — everything needed to verify future logins.

Bcrypt vs Argon2

While bcrypt is widely used and secure, modern applications increasingly adopt Argon2id, which offers better resistance against GPU and ASIC attacks. For new applications, OWASP recommends Argon2id as the preferred password hashing algorithm. Try our Argon2 Password Hash Generator for modern password security.

Algorithm	Strength	GPU Resistance	Recommended For
Bcrypt	Strong	Moderate	Existing systems
Argon2id	Very Strong	High	New applications

Advantages

Brute-Force Resistant — slow hashing and salting make dictionary attacks impractical
Adjustable Work Factor — scale security as hardware improves without changing your code
Widely Trusted — battle-tested across millions of production systems for decades

Limitations

Intentionally Slow — can impact performance under high-volume authentication scenarios
72-Byte Limit — passwords longer than 72 bytes are silently truncated by bcrypt
No Memory Hardness — unlike Argon2id, bcrypt does not resist memory-efficient GPU attacks as effectively

Python Example

Here's a basic example of how bcrypt is used in code:

# Install: pip install bcrypt import bcrypt # Generating a salt and hashing password = b"supersecret" hashed = bcrypt.hashpw(password, bcrypt.gensalt(rounds=12)) # Verifying a password if bcrypt.checkpw(password, hashed): print("Password match!") else: print("Password does not match.")

Usage Guide

Enter any plain text in the Generate panel and choose a salt round (12 is recommended). Click Generate Hash to produce the bcrypt hash.
The salt is random — the same password produces a different hash each time. This is expected and correct behavior.
To verify a password, paste the stored bcrypt hash and the candidate plain text in the Verify panel and click Match.
Hashes starting with $2a$ vs $2y$ are different bcrypt variants. Some older systems only accept $2a$ . If verifying fails, check the prefix and cost factor match.
For migrating to newer rounds, re-hash the user's password on next login using the updated cost factor — no need to force a password reset.

Frequently Asked Questions

What is bcrypt used for?

Bcrypt is a password hashing algorithm designed for secure password storage. It incorporates automatic salting and an adjustable cost factor to resist brute-force and rainbow table attacks. It is not suitable for encrypting data — only for one-way password hashing.

Is bcrypt still secure in 2025?

Yes, bcrypt remains secure when used with an appropriate cost factor (12 or higher). However, Argon2id is OWASP's current recommendation for new applications because it offers memory-hard resistance against GPU-based attacks.

What bcrypt cost factor should I use?

A cost factor of 12 is recommended for most modern systems — it hashes in roughly 250ms, which is acceptable for login flows. High-security systems may use 13 or 14, as long as server response times stay within user expectations. Benchmark on your own hardware to choose wisely.

Can bcrypt hashes be reversed or decrypted?

No. Bcrypt is a one-way function — hashes cannot be reversed to retrieve the original password. Verification works by re-hashing the candidate password with the stored salt and comparing the result.

What is the difference between $2a$ and $2y$ bcrypt hashes?

$2a$ is the original bcrypt prefix; $2y$ was introduced to fix a bug in PHP's implementation. Both are functionally equivalent in most modern libraries. If verifying fails across systems, check that the prefix and cost factor match what was used during generation.

Does bcrypt have a password length limit?

Yes. Bcrypt silently truncates passwords longer than 72 bytes. For users with very long passphrases, this means only the first 72 bytes are hashed. If this is a concern, pre-hash the password with SHA-256 before passing it to bcrypt.

How does this tool keep my data private?

This tool processes all hashing server-side and does not store, log, or transmit any input. No account is required. We recommend not using any online tool for production secrets — generate and store hashes within your own secure infrastructure.

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