How Bcrypt Generator Works
Bcrypt is a sophisticated password hashing algorithm designed specifically to thwart "Brute-Force" and "Rainbow Table" attacks. Unlike standard cryptographic hashes like MD5 or SHA-256, which are designed to be extremely fast, Bcrypt is intentionally designed to be slow and resource-intensive. This "Computational Slowness" is the primary defense that makes it the industry standard for securing user passwords in Web Applications.
The Bcrypt engine utilizes a specialized "Eksblowfish" (Expensive Blowfish) architecture:
- Salt Generation: Every password is combined with a unique, random "Salt." This ensures that even if two users have the same password, their resulting hashes will be completely different.
- Cost Factor (Work Factor): The algorithm takes a "Cost" parameter (typically between 10 and 12). This number dictates how many iterations of the hashing process will occur ($2^{cost}$). As hardware becomes faster, developers can simply increase the cost factor to keep the system secure.
- Key Expansion: The password and salt are expanded into a large internal state through thousands of cycles of the Blowfish cipher.
- Round Processing: The password undergoes repeated iterations of mixing and shuffling. Because this process requires significant CPU and Memory, it prevents attackers from using massive GPU arrays to guess passwords quickly.
- Output Formatting: The final hash is outputted in a standardized string (e.g.,
$2a$12$R9h/cIPz...) that includes the algorithm version, the cost factor, the salt, and the checksum all in one.
The History of Bcrypt and Niels Provos
Bcrypt was designed by Niels Provos and David Mazières and presented at the USENIX association in 1999. It was based on the Blowfish cipher by Bruce Schneier.
Provos and Mazières realized that as Moore's Law made computers faster, simple hash functions would become dangerously easy to crack. Their breakthrough was to create an algorithm with a "Work Factor" that could be adjusted over time. Today, Bcrypt is the default password hashing mechanism for OpenBSD, Node.js (bcrypt.js), and major frameworks like Ruby on Rails and Laravel.
Technical Comparison: Bcrypt vs. Argon2 vs. PBKDF2
Choosing the right hashing strategy is a balance between security and server resource availability.
| Feature | Bcrypt (Eksblowfish) | Argon2 (Winner of PHC) | PBKDF2 (NIST Standard) |
|---|---|---|---|
| Primary Strength | CPU Intensive | Memory Intensive | Scalable Iterations |
| GPU Resistant? | Yes | Extremely Yes | Low |
| Work Factor | Logarithmic ($2^n$) | Parallelism / Memory | Linear (Count) |
| Common Use | General Auth / Web | Crypto-wallets / High-security | Standard Compliance |
| Released | 1999 | 2015 | 2000 |
By using our dedicated Bcrypt Generator, you can accurately test your Password Validation logic or manually verify hashes from your database with absolute precision.
Security Considerations: Salts and Brute-Force
Bcrypt is designed as a "Future-Proof" security wall:
- Salt-by-Default: Every hash generated by this tool includes a cryptographically secure, random salt. This prevents "Rainbow Table" attacks, where hackers use pre-calculated lists of common passwords.
- The "Cost" Trade-off: A cost of 10 might take 100ms per hash, while a cost of 12 takes 400ms. While this adds a small delay for a user logging in, it makes it impossible for an attacker to try millions of combinations per second.
- Maximum Length: Standard Bcrypt has a maximum password length of 72 characters. Passwords longer than this are typically truncated, which is why many systems pre-hash long passwords with SHA-256 before sending them to Bcrypt.
- Client-Side Privacy: To maintain the absolute Data Privacy of your information, all hashing happens locally in your browser. Your sensitive passwords and secret salts are never sent to our servers.