Bcrypt

bcrypt is a cryptographic hashing algorithm used for securing passwords. It was designed to build a cryptographically secure hash that is resilient against brute-force search attacks, even with increasing computation power.

The bcrypt algorithm is particularly notable for incorporating a salt (a random value) automatically and allowing the specification of a computational cost (work factor), which can be adjusted as hardware capabilities improve.

It automatically generates and applies a salt to each password. This prevents the use of rainbow tables (precomputed tables used to crack password hashes). It also allows the specification of the computational complexity (work factor), making the hash calculation slower. As hardware gets faster, the work factor can be increased to make brute-force attacks more difficult and time-consuming.

As computing power increases, the algorithm can be adjusted to be more computationally intensive, providing long-term security.

In PHP, bcrypt is commonly used for password hashing and is accessible through the password_hash() and password_verify() functions, which were introduced in PHP 5.5.0. These functions simplify secure password hashing and verification.

For example, hashing a password:

$password = "user_password";
$hash = password_hash($password, PASSWORD_BCRYPT);

This creates a hashed version of the password using bcrypt.

You can also verify a password:

$isPasswordCorrect = password_verify($password, $hash);

This checks a password against its hashed version and returns True if they match.

bcrypt is a robust algorithm that provides strong protection against password cracking. PHP's built-in functions abstract the complexities of salt generation and hash comparison, reducing the risk of implementation errors. The ability to adjust the work factor means bcrypt can remain secure against increasing computational power.