What is bcrypt?

bcrypt is a password hashing algorithm designed to be slow and computationally expensive, making it resistant to brute-force attacks. Unlike fast hash functions like MD5 or SHA-256, bcrypt intentionally takes more time to compute, which significantly increases the cost for attackers trying to crack passwords.

Why Use bcrypt?

Adaptive Cost Factor

You can increase the number of rounds as hardware gets faster, keeping your hashes secure over time

Built-in Salt

Each hash includes a unique random salt, preventing rainbow table attacks

Industry Standard

Used by major frameworks including Laravel, Ruby on Rails, Django, and Spring Security

Battle-Tested

Based on the Blowfish cipher, in use since 1999 with no known practical vulnerabilities

Understanding bcrypt Hash Format

Example hash: $2b$12$WApznUPhDubN0oeveSFPpOLo0dVMFJ.3CC9TmGkMxLFvnEGbgm4jq

$2b$

Algorithm version (2b is the current standard)

12

Cost factor (rounds = 2^12 = 4,096 iterations)

22 Characters

The salt (Base64 encoded)

31 Characters

The hash (Base64 encoded)

Table of Contents

1. What is bcrypt?
- 1.1. Why Use bcrypt?
- 1.2. Understanding bcrypt Hash Format
2. How to Use
3. Features
4. Frequently Asked Questions

How to Use

Generate a bcrypt Hash

Select Generate Tab

Make sure the Generate tab is selected in the tool interface

Enter Password

Type your password in the input field

Choose Cost Factor

Select the number of rounds — the default of 12 is recommended for most use cases

Generate

Click Generate Hash button to create your bcrypt hash

Copy Result

Use the copy button to copy the resulting hash to your clipboard

Verify a Password

Switch to Verify Tab

Click on the Verify tab in the tool interface

Enter Password

Type the password you want to check

Paste Hash

Paste the bcrypt hash you want to verify against

Verify

Click Verify Password button to check if they match

Check Result

The result will show Match (green) or Mismatch (red)

Choosing the Right Cost Factor

Recommendation: For most production applications, use 12 rounds for optimal balance between security and performance.

Rounds	Security Level	Use Case
4–9	Low	Development and testing only
10–11	Medium	Low-security applications
12–13	Recommended	Production applications
14–17	High	High-security systems
18+	Very High	Maximum security (slow generation)

Features

Two Modes: Generate & Verify

Switch between generating new bcrypt hashes and verifying existing ones with a single click.

Generate mode creates new hashes from passwords
Verify mode checks password against existing hash
Seamless switching between modes

Adjustable Cost Factor

Choose from rounds 4 to 31 to control the hashing strength with color-coded security badges.

Visual security level indicators
Balance security vs. performance
Higher rounds = stronger security

Detailed Hash Information

View algorithm version, cost factor, and exact generation time to understand performance impact.

Algorithm version display
Cost factor breakdown
Real-time performance metrics

Client-Side Security

All password hashing and verification happens entirely in your browser using bcryptjs library.

No server transmission
Complete privacy protection
Works offline

Privacy First: Your passwords never leave your browser. All operations are performed locally using JavaScript.

Frequently Asked Questions

Why does the same password produce different hashes?

bcrypt automatically generates a unique random salt for each hash. This means even identical passwords will produce completely different hashes, which prevents attackers from using precomputed tables (rainbow tables) to crack passwords.

Security benefit: Each hash is unique, making rainbow table attacks impossible even for common passwords.

What cost factor should I use?

For most production applications, 12 rounds is recommended. This provides a good balance between security and performance.

Use 12 rounds for standard production applications
Use 14+ rounds for highly sensitive data
Use 4-8 rounds for development and testing only

Important: Higher cost factors significantly increase processing time. Test performance impact before deploying to production.

What is the difference between $2a$, $2b$, and $2y$?

$2a$

Original bcrypt specification

$2b$

Updated version fixing long password handling

$2y$

PHP implementation identifier

All three versions are compatible — this tool generates $2b$ hashes and can verify all three formats.

Is there a maximum password length?

bcrypt processes up to 72 bytes of input. Characters beyond this limit are silently truncated.

For long passphrases: If you need to hash very long passphrases, consider pre-hashing with SHA-256 before applying bcrypt.

For most passwords this is not an issue, as typical passwords are well under 72 characters.

Is my password safe when using this tool?

Yes, absolutely. All hashing and verification is performed entirely in your browser using JavaScript. Your password is never transmitted to any server.

100% client-side processing
No server communication
Works offline
No data logging or storage

Verify yourself: You can test this by using the tool while disconnected from the internet — it will work perfectly.