BCrypt hashed passwords and secrets have 72 character limit | Ory (2024)

FAQs

What is the character limit for bcrypt? ›

BCrypt hashed passwords and secrets have a 72 character limit. This is a limitation of the BCrypt algorithm and the Golang BCrypt library.

Bcrypt is a valuable tool to use to hash and store passwords. Its major benefits include: Slow runtime. Bcrypt is a slow-functioning algorithm that takes time to create password hashes and requires time to decrypt them, significantly slowing hacker attempts to break the bcrypt hash.

bcrypt is just obsolete – this was to find a successor to it. yescrypt, one of the recommended finalists, is an improved/fixed version of scrypt. "Obsolete" is a very strong word for bcrypt.

To protect against dictionary and brute force attacks, bcrypt deploys salting, where a unique addition is made to each password hash. This process significantly complicates deciphering, augmenting password complexity, and thwarting common hacking tactics.

While bcrypt hashing offers significant protection, it's important to note that it isn't a fail-safe solution against password compromise.

Bcrypt is slower and requires some memory (4 kiB IIRC), so one spends 100ms to check a valid password whereas an attacker needs days / years to crack it because he's slowed down and can't use GPUs efficiently.

How to decrypt an encrypted password in Mendix app set to bcrypt? You cannot do this because: Passwords are hashed, not encrypted. Hashing is one way only, you cannot reverse it.

To verify a password using bcrypt, use the bcrypt. compare() function. This function compares a plaintext password provided by the user during login with the hashed password stored in the database.

You can't “decrypt” a hash password because it's designed as such. Storing passwords in plain text is a recipe for disaster, leaving them vulnerable to breaches and unauthorized access. Hashing, on the other hand, provides an impenetrable layer of protection.

Even with higher computer speeds, bcrypt is very time-consuming to hack via brute force thanks to its variable number of password iterations. Compare this to popular hashing algorithms such as MD5 and SHA256, which are designed to hash quickly.

Does bcrypt use a key? ›

BCrypt is not a key-derivation function; it is a password storage function. You cannot use bcrypt to generate a "key". For example if you wanted "derive" an AES-256 bit key: bcrypt cannot do it.

If you want to store passwords, then bcrypt, scrypt, and argon2 are commonly used. They are available in Go's extended library. SHA is a hashing algorithm but by itself is not meant for password storage. Unlike bcrypt, scrypt and argon2, SHA is designed to be fast.

Strong security: Bcrypt is designed to be resistant to various password-cracking techniques, including brute force, rainbow table, and dictionary attacks. The combination of salting, key stretching, and variable-length password support greatly enhances the security of stored passwords.

Bcrypt uses a 128-bit salt and encrypts a 192-bit magic value. It takes advantage of the expensive key setup in eksblowfish.

AES ‍ One of the hardest codes to crack is arguably the US government's Advanced Encryption Standard (aka Rijndael or AES) which the Americans use to protect top-secret information. AES is considered unbreakable by even the most sophisticated hackers.

bcrypt has a maximum length input length of 72 bytes for most implementations, so you should enforce a maximum password length of 72 bytes (or less if the bcrypt implementation in use has smaller limits).

Absolute Maximum Length for JSON Text Data

8388096 UNICODE characters or 16776192 LATIN characters are equivalent to 16776192 bytes, which is the absolute maximum length for the JSON type. If no maximum length is specified, the default maximum length for the character set is chosen.

bcrypt uses a 128-bit salt and encrypts a 192-bit magic value. It takes advantage of the fact that the Blowfish algorithm (used in the core of bcrypt for password hashing) needs a fairly expensive key setup, thus considerably slowing down dictionary-based attacks.