How do I sign and verify images for Process isolation?

In the realm of process isolation, signing and verifying images is crucial for maintaining security and ensuring that the images come from a trusted source. By using digital signatures, you can prevent unauthorized modifications and ensure integrity during the deployment process.

    // Example of signing an image
    $imagePath = 'path/to/image';
    $privateKey = 'path/to/private_key.pem';
    $signature = '';
    
    // Create a signature of the image
    openssl_sign(file_get_contents($imagePath), $signature, $privateKey, OPENSSL_ALGO_SHA256);
    
    // Save the signature to a file
    file_put_contents('path/to/image.sig', $signature);

    // Example of verifying an image
    $publicKey = 'path/to/public_key.pem';
    $signature = file_get_contents('path/to/image.sig');
    
    $isVerified = openssl_verify(file_get_contents($imagePath), $signature, $publicKey, OPENSSL_ALGO_SHA256);
    
    if ($isVerified === 1) {
        echo "Image is verified and trusted.";
    } elseif ($isVerified === 0) {
        echo "Image verification failed.";
    } else {
        echo "Error in verification.";
    }