How to Securely Hash Passwords in PHP While Balancing Speed and Security?

Secure Password Hashing with Salts in PHP

Question:

• What are the best practices for secure password protection in PHP, considering the limitations of MD5 and the need for balance between speed and security?

Answer:

Hashing Mechanism and Salt

• In PHP, bcrypt is the recommended password hashing mechanism. It uses a computationally intensive function called blowfish, making it difficult to brute-force passwords.
• A salt is a random value added to the password before hashing, which prevents identical passwords from producing the same hash. It improves security against rainbow table attacks.
• Good salts have high entropy, ensuring uniqueness and unpredictability.

Choosing a Hashing Function

• Bcrypt is the most secure option.
• If bcrypt is unavailable, use scrypt, PBKDF2 with SHA2 hashes, or PHPASS (legacy option).

Best Practices

• Avoid restricting password characters or length.
• Enforce a reasonable minimum password length (e.g., 10 characters).
• Require a combination of upper and lowercase letters, numbers, and symbols to increase password entropy.
• Reset passwords after database compromises.

Additional Considerations

• Storing multiple hashed passwords (e.g., using different algorithms) is not recommended as it adds complexity without significant security benefits.
• Avoid using hash() with bcrypt, as it requires hex or base64 encoding to prevent the introduction of rogue characters that weaken security.

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