Bcrypt Generator — Hash & Verify Passwords the Right Way

Storing passwords in plain text is one of the most consequential security failures a developer can make

When a database is breached — and databases get breached — the damage is entirely different depending on how passwords were stored. Plain text: every user's password is immediately compromised, and since most people reuse passwords, the attacker now has access to their email, bank, and everything else. Bcrypt-hashed: the attacker gets a pile of slow-to-crack hashes that take years of GPU time to partially crack.

Bcrypt is the industry standard for password hashing. It's specifically designed to be slow — which is a feature, not a bug.

What Bcrypt Does

Bcrypt is a password hashing function with built-in adaptive cost. It takes a password and produces a hash that:

1. Cannot be reversed. You can't get the password back from the hash.
2. Is slow by design. The "cost factor" or "work factor" controls how many iterations of hashing run — higher cost = slower hash = harder to crack by brute force.
3. Includes a salt. A random value mixed into the hash prevents rainbow table attacks — two identical passwords produce different hashes.
4. Is self-contained. The hash string includes the cost factor and salt, so you don't need to store these separately.

A bcrypt hash looks like:

$2b$12$EixZaYVK1fsbw1ZfbX3OXePaWxn96p36WQoeG6Lruj3vjPGga31lW

Breaking this down:

• $2b$ — bcrypt version identifier
• 12 — cost factor (2^12 = 4,096 iterations)
• EixZaYVK1fsbw1ZfbX3OXe — the 22-character salt (128 bits)
• PaWxn96p36WQoeG6Lruj3vjPGga31lW — the 31-character hash

The Cost Factor

The cost factor is the most important security parameter. At cost 12 on a modern CPU, bcrypt takes approximately 200–300ms to hash one password. This is intentionally slow.

Why slowness matters for security:

• Password verification for a legitimate user: 0.3 seconds — imperceptible
• An attacker trying to crack 1 million passwords by brute force: 0.3s × 1,000,000 = 83 hours per attempt cycle — impractical

Compare to MD5 or SHA1 (which should NOT be used for passwords): a modern GPU can test billions of MD5 hashes per second. An entire leaked password database could be cracked in hours.

Cost factor guidelines (as of 2024):

• Minimum: 10 (bcrypt was designed when hardware was slower; 10 is now too fast on modern hardware for high-security applications)
• Recommended: 12–13 (good balance of security and performance)
• High security: 14+ (significantly slower; use for especially sensitive accounts)

At each cost level, hashing takes approximately twice as long as the previous level (cost 13 ≈ 2× cost 12). As hardware gets faster, increase the cost factor.

How to Use the Bcrypt Generator on sadiqbd.com

Hashing a password:

1. Enter the password you want to hash
2. Set the cost factor (default: 12)
3. Generate — the bcrypt hash is produced instantly
4. Copy the hash to store in your database

Verifying a password:

1. Enter the plaintext password
2. Enter the stored hash
3. Verify — the tool confirms whether the password matches the hash

Bcrypt in Practice

User registration

import bcrypt

password = b"user_input_password"
hashed = bcrypt.hashpw(password, bcrypt.gensalt(rounds=12))
# Store `hashed` in database

User login verification

stored_hash = get_hash_from_database(username)
if bcrypt.checkpw(submitted_password.encode(), stored_hash):
    # Login successful
else:
    # Wrong password

The checkpw function extracts the salt from the stored hash, re-hashes the submitted password, and compares — all in one call. You never store the password.

Why verification works without storing the salt separately

The bcrypt hash includes the salt in its output string. $2b$12$EixZaYVK1fsbw1ZfbX3OXe... contains the salt as part of the hash. When you call checkpw, the library parses the hash, extracts the salt, applies it to the submitted password, and compares the result.

Bcrypt vs. Other Password Hashing Methods

Never use MD5, SHA-1, or SHA-256 directly for password hashing. They're designed to be fast — which is exactly wrong for passwords. They're appropriate for data integrity (verifying a file hasn't changed) but not authentication.

Common Bcrypt Mistakes

Not using bcrypt at all. Still happening in 2024. Every week brings news of another breach exposing plain text or MD5-hashed passwords.

Using a cost factor of 4 or 6. Too fast — essentially negates the protection bcrypt is designed to provide. Use at least 10; prefer 12+.

Bcrypt's 72-character limit. Bcrypt only processes the first 72 bytes of the password. Passwords longer than 72 characters are truncated before hashing. If your users might set very long passwords, consider pre-hashing with SHA-256 before bcrypt (though this is controversial — modern alternatives like Argon2id don't have this limitation).

Comparing hashes with string equality. Don't compare stored_hash == new_hash. Use the timing-safe comparison provided by the bcrypt library (checkpw) to prevent timing-based attacks.

Frequently Asked Questions

Can I use the Bcrypt generator to hash passwords for production systems? The generator is for learning, testing, and verification — not for production hashing. In production, use your language's bcrypt library server-side (Python: bcrypt, Node.js: bcryptjs, PHP: password_hash). Never hash passwords client-side.

What's the difference between bcrypt, scrypt, and Argon2? All three are slow password hashing functions. bcrypt (1999) is well-tested and widely supported. scrypt (2009) adds memory-hardness. Argon2 (2015, winner of the Password Hashing Competition) is the modern recommendation for new systems — more configurable than bcrypt, not subject to bcrypt's 72-byte limit.

Is the bcrypt generator free? Yes — completely free, no sign-up required.

Password hashing is not optional infrastructure — it's the minimum standard for handling user credentials responsibly. Bcrypt remains one of the most widely deployed and well-supported options. The generator makes it accessible for learning and verification.

Try the Bcrypt Generator free at sadiqbd.com — hash any password with configurable cost factor, or verify a password against an existing hash.