Which Password Hashing Algorithm is Best for Secure PHP Logins: SHA1, MD5, SHA256, or bcrypt?

Password Hashing in PHP: SHA1, MD5, SHA256 vs. Bcrypt

When designing a secure PHP login system, the choice of password hashing algorithm is crucial. While SHA1, MD5, and SHA256 have traditionally been used, they are vulnerable to cracking due to their fast computation.

Recommendation: Use Bcrypt Instead

For optimal security, it is recommended to abandon the mentioned hashing algorithms and instead adopt bcrypt. Bcrypt is designed to be computationally intensive, making it highly resistant to cracking.

bcrypt Implementation in PHP

PHP 5.5 and later provide built-in functions for bcrypt hashing:

<code class="php">// Creating a hash
$hash = password_hash($password, PASSWORD_DEFAULT, ['cost' => 12]);

// Verifying the password against the stored hash
if (password_verify($password, $hash)) {
    // Success! Log the user in.
}</code>

Generating Salt

Bcrypt automatically generates a salt using a cryptographically secure pseudorandom number generator (CSPRNG). It is therefore unnecessary to manually generate and combine a salt with the password.

Cautions with bcrypt

• Bcrypt silently truncates passwords longer than 72 characters.
• Bcrypt truncates passwords after any NUL characters.

To mitigate these issues, avoid using password hashing libraries that pre-hash passwords before running them through bcrypt. Instead, opt for reputable libraries like ZendCrypt or PasswordLock that handle hashing securely.

Conclusion

While SHA1, MD5, and SHA256 were once considered acceptable hashing algorithms, they are no longer recommended for PHP logins due to their vulnerability to cracking. Bcrypt has emerged as the preferred choice for secure password storage, offering a higher level of protection against unauthorized access.

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