Can a bcrypt hash be decrypted or reversed?

No. Bcrypt is a one-way cryptographic key derivation hash function based on the Blowfish cipher. It is mathematically designed to be non-reversible. The only way to find a password is by guessing (brute-force or dictionary search) and running each guess through bcrypt to test for a match.

Why does the same password generate different hashes each time?

Bcrypt incorporates a fresh, cryptographically random 128-bit (16-byte) salt into every hash. Even if you hash the exact same password seconds apart, different salts are used, yielding completely unique 60-character hash outputs. This completely neutralizes precomputed rainbow table attacks.

What cost factor (rounds) should I use?

A cost factor between 10 and 12 is recommended for modern web applications. Each increment of the cost factor doubles the hashing computation time (2^rounds key expansion iterations). Aim for a verification time between 150ms and 350ms on your production server.

Is my password sent over the network when using this tool?

Never. All hashing and verification logic is performed 100% locally in your browser using client-side JavaScript. No passwords, salts, or generated hashes are ever sent to or logged by our servers.

What does the 60-character bcrypt hash format mean?

A standard bcrypt hash has four segments separated by '$': $2b$ (algorithm identifier), $12$ (work factor cost rounds), followed by a 22-character Radix-64 encoded salt and a 31-character Blowfish ciphertext checksum.

Bcrypt Hash Generator & Verifier

Generate salted bcrypt password hashes with customizable cost rounds (4–16) and test existing hashes against plain text in real time. 100% private, client-side execution.

Client-Side Privacy Free Forever Mobile & PC

100% Client-Side Encryption: All bcrypt hashing and verification runs in your browser via WebAssembly/JavaScript. No passwords or hashes are ever transmitted over the network.

Generate Hash

Hash a password or text string using bcrypt

Text or Password to Hash

Samples:

Rounds (Cost Factor):12

Recommended for Production

Calculates 2^12 (4,096 iterations). Cost factor 12 is current industry best practice.

Verify Hash

Check if an existing bcrypt hash matches a plaintext string

Bcrypt Hash String ($2a$, $2b$, or $2y$)

Original Password / Text

Anatomy of a Bcrypt Hash String

Unlike standard hashes (such as MD5 or SHA-256), a bcrypt hash string self-contains the algorithm identifier, cost factor, salt, and hash checksum in a single 60-character string:

$2b$12$e8UvVpWvI.7rY9xPZq82.OJq9Yv1hXm58.Y9Zp7W2Q0v18.M9x8

$2a$ / $2b$ / $2y$Bcrypt algorithm variant. $2b$ is the modern standard used in OpenBSD and modern libraries.

12 (Cost Factor)Work factor. Represents 2^12 (4,096) Blowfish key scheduling rounds.

22-Char Salt128-bit cryptographically random salt encoded in Radix-64 to defend against rainbow tables.

31-Char Checksum184-bit ciphertext produced by encrypting "OrpheanBeholderScryDoubt" 64 times.

How to Implement Bcrypt in Your Code

// npm install bcryptjs
import bcrypt from "bcryptjs";

// 1. Hash a password
const saltRounds = 12;
const hash = await bcrypt.hash("userPassword123", saltRounds);

// 2. Verify during login
const isMatch = await bcrypt.compare("candidatePassword", hash);
if (isMatch) {
  // Login successful
}

Understanding Bcrypt Password Hashing

Everything you need to know about the Blowfish-based adaptive key derivation function.

What is Bcrypt?

Designed in 1999 by Niels Provos and David Mazières for OpenBSD, bcrypt is a cryptographic hash function based on the Blowfish symmetric cipher. Unlike fast general-purpose hashing algorithms like MD5 or SHA-256, bcrypt is deliberately designed to be computationally slow and resource-intensive to mitigate brute-force and dictionary attacks.

The Work Factor (Cost Rounds)

Bcrypt features an adjustable work factor parameter (e.g. 10 to 14 rounds). The algorithm executes 2^cost key expansion iterations. For instance, rounds=12 runs 4,096 iterations. As computing power and GPUs advance, administrators can simply increment the cost parameter without altering the underlying system architecture.

Structure of a 60-Character Bcrypt Hash

Every bcrypt hash follows a standardized layout: $[revision]$[cost]$[salt + checksum]. For example: $2b$12$e8Y... (2 bytes prefix) + $12$ (2 digits cost) + 22 characters base64-encoded salt + 31 characters Blowfish ciphertext checksum = 60 total characters.

Bcrypt vs. Fast Hashes (MD5, SHA-256)

Fast hashing algorithms like SHA-256 can be computed tens of billions of times per second on consumer GPUs, allowing attackers with stolen database dumps to crack short passwords in seconds. Bcrypt's high memory and CPU cost forces attackers to spend hundreds of milliseconds per guess, making mass offline cracking virtually impossible.

Our Tool Features

Why developers and engineers prefer this tool for everyday development workflows.

Cross-Device Compatibility

Works seamlessly on all modern desktop, tablet, and mobile browsers including Chrome, Firefox, Safari, Edge on Windows, macOS, Linux, Android, and iOS.

Fast In-Browser Execution

Processes your data in real-time directly inside your browser. No queue wait times, no network round-trips, and zero latency.

100% Client-Side Privacy

Your code, tokens, passwords, and files are never transmitted to any external server or saved in logs. Everything runs locally in memory.

Instant File & Clipboard Input

Supports one-click sample loading, file drag-and-drop, and pasting directly from your clipboard (Ctrl + V) for effortless workflows.

Strict Standards Compliant

Built strictly according to official specifications (RFCs, W3C, ISO, and standard cryptographic algorithms) ensuring accurate output every time.

Unlimited Free Usage

No registration, no accounts, no subscriptions, and no hidden daily quotas. Use this tool as many times as you need without restrictions.

Recent Updates & Improvements

Continuously maintained and improved based on developer feedback.

Client-Side Speed & Performance UpgradeRecent Update

Optimized processing algorithms with Web Workers and native browser APIs (SubtleCrypto, Canvas 2D) for instantaneous zero-latency execution.

Clipboard Paste & Drag-and-Drop AddedFeature Added

Added instant clipboard pasting (Ctrl + V) and drag-and-drop file support to accelerate developer productivity without manual downloads.

Enhanced Mobile & Touch Device ExperienceUI/UX Update

Redesigned responsive touch controls, flexible copy buttons, and camera preview framing for mobile and tablet browsers.

Frequently Asked Questions

Related Tools

Explore all 40+ tools →

JWT Debugger

Decode, verify, and generate JSON Web Tokens in the browser. Check HMAC signatures and inspect claims with 100% privacy.

URL Encoder & Decoder

Encode and decode URLs and query string parameters online with full UTF-8 percent-encoding support.

Text Hash Generator

Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes simultaneously in real-time. 100% private, client-side Web Crypto.

File Hash Generator

Compute MD5, SHA-1, SHA-256, and SHA-512 checksums client-side without uploading files. Verify file integrity privately.

HMAC Generator

Generate Keyed-Hash Message Authentication Codes (HMAC-SHA256, HMAC-SHA512, HMAC-SHA1) in Hex and Base64.

Hash Identifier

Identify unknown hash types from length, character set, and format prefixes: MD5, SHA-1, SHA-256, SHA-512, bcrypt, Argon2.

// npm install bcryptjs import bcrypt from "bcryptjs"; // 1. Hash a password const saltRounds = 12; const hash = await bcrypt.hash("userPassword123", saltRounds); // 2. Verify during login const isMatch = await bcrypt.compare("candidatePassword", hash); if (isMatch) { // Login successful }

Understanding Bcrypt Password Hashing

Everything you need to know about the Blowfish-based adaptive key derivation function.