bigb06/phpcypherfile

A PHP library for encrypting and decrypting files using the AES-256-CBC algorithm.

v1.0.2 2025-02-14 08:30 UTC

Requires

• php: >=8.2
• ext-openssl: *

MIT

• Nicolas Chevallier

README

PHPCypherFile provides a robust solution for encrypting large files securely without significant memory overhead. It combines the power of RSA for public/private key encryption and AES-256-CBC for symmetric encryption, ensuring both performance and security.

Features

1. Large File Support:

   Files are encrypted in chunks, minimizing memory usage during the encryption/decryption process. This ensures scalability for handling large files.

2. Hybrid Encryption Scheme:

   • random symmetric key is generated for AES-256-CBC encryption of the file content.
   • The symmetric key and IV (Initialization Vector) are encrypted with a public RSA key.

3. Output Structure: The encrypted file includes the following components:

   • RSA-encrypted symmetric key.
   • RSA-encrypted IV.
   • AES-encrypted file data.

4. Security Standards:

   • AES-256-CBC ensures high-speed, secure encryption for the data.
   • RSA encryption secures the transmission of the symmetric key, leveraging a public/private key pair.

5. Minimal Memory Footprint:

   By processing files in small chunks, the class avoids loading the entire file into memory.

Installation

To install this library, you can use Composer. Run the following command:

composer require bigb06/phpcypherfile

Example

Basic code to use PHPCypherFile (see example.php for full example and keys generation):

use PHPCypherFile\PHPCypherFile;

// Encrypt the file
PHPCypherFile::encryptFile($inputFile, $encryptedFile,$publicKey);

// Decrypt the file
PHPCypherFile::decryptFile($encryptedFile, $decryptedFile,$privateKey);

Keys Generation

$config = [
    "private_key_bits" => 4096,
    "private_key_type" => OPENSSL_KEYTYPE_RSA,
];
$res = openssl_pkey_new($config);
openssl_pkey_export($res, $privateKeyString);
$details = openssl_pkey_get_details($res);
$publicKeyString = $details["key"];
$publicKey = openssl_pkey_get_public($publicKeyString);
$privateKey = openssl_pkey_get_private($privateKeyString);

You can also refer to example.php for detailed steps on how to generate the required RSA public/private keys for encryption and decryption.

🙇 Author

• Nicolas Chevallier Linkedin Bio

🙇 Acknowledgements

• Antoine Lame for the inital idea

License

This project is open source and available under the MIT License.