What are the differences between hash_hmac_file() and hash_file() functions? How should you choose between them?

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echo "<h1>What are the differences between hash_hmac_file() and hash_file() functions? How should you choose between them?</h1>";
echo "<p>In PHP, processing file hashes is a common requirement, especially when verifying file integrity or preventing tampering. PHP provides two commonly used functions: <code>hash_file()

The purpose of HMAC is not only to generate a hash but also to ensure that the data has not been tampered with. Since the key is used in the hash calculation, even if an attacker obtains the file, they cannot forge a correct HMAC value without knowing the key.

3. Summary of differences

• Security: hash_file() only generates a regular hash and lacks tampering prevention; hash_hmac_file() uses a key to generate HMAC, making it more secure.
• Use case: hash_file() is suitable for file integrity checking or deduplication; hash_hmac_file() is better for ensuring the file hasn't been tampered with, especially in client-server interactions.
• Parameters: hash_file() requires only an algorithm and a file path; hash_hmac_file() also requires a key.

4. Recommendation

If you only need to verify that the file has not been corrupted during transmission, hash_file() is sufficient. However, if you need to prevent tampering or perform secure validation, hash_hmac_file() is a better choice.

In summary: hash_file() is more suited for integrity checks, while hash_hmac_file() is more focused on security and tamper prevention. Choose based on your actual needs.