Laravel 5.6与TCPDF公钥加密实现求助（PKI新手）

云上老周

2026-5-20

Hey there! Since you're new to PKI and looking to add public key encryption to your Laravel 5.6 project using elibyy/tcpdf-laravel, let's break this down into actionable steps that fit your workflow:

Step 1: Generate Your RSA Key Pair

First, you'll need a valid RSA public/private key pair. Use OpenSSL to generate them (most servers have this installed by default):

# Generate 2048-bit private key
openssl genrsa -out private.key 2048
# Extract corresponding public key
openssl rsa -in private.key -pubout -out public.key

Store these files in a secure directory in your project, like storage/app/keys/ (make sure to set proper file permissions so only your app can read them).

Step 2: Modify Your PDF Generation Logic

The elibyy/tcpdf-laravel package wraps TCPDF's core functionality, so you can directly use TCPDF's built-in public key encryption method. Here's how to integrate it into your existing workflow:

Replace AES Password Encryption with Public Key Encryption

If your current code looks something like this for password protection:

use PDF;

$pdf = PDF::loadView('contracts.signed', $contractData);
// Old AES 256 password encryption
$pdf->setEncryption('user_pass', 'owner_pass', '', 0, 256);
return $pdf->download('signed_contract.pdf');

Update it to use public key encryption instead:

use PDF;

// Load your public key
$publicKeyPath = storage_path('app/keys/public.key');
$publicKey = file_get_contents($publicKeyPath);

// Prepare recipient data (you can add multiple recipients if needed)
$recipients = [
    [
        'certs' => $publicKey,
        'name' => 'Contract Recipient' // Optional, for metadata
    ]
];

// Generate PDF from your contract view
$pdf = PDF::loadView('contracts.signed', $contractData);

// Enable public key encryption (leave password fields empty)
$pdf->setEncryption(
    '', // User password (unused for public key encryption)
    '', // Owner password (unused for public key encryption)
    '', // Permissions (default is all restricted)
    0, // Mode (0 = standard encryption)
    256, // Encryption strength (256-bit AES)
    $recipients // Array of public key recipients
);

// Output or save the encrypted PDF
return $pdf->download('encrypted_signed_contract.pdf');

Step 3: Integrate with Your Business Flow

To tie this to your user's checkbox + completion action:

Create a controller method that handles the form submission after the user signs and checks the box
Validate that the checkbox is checked (e.g., using Laravel's validation rules)
Run the PDF generation + encryption logic above
Either save the encrypted PDF to your storage or send it directly to the user for download

Key Notes & Troubleshooting

OpenSSL Requirement: Ensure your PHP environment has the OpenSSL extension enabled (it's usually enabled by default in Laravel setups, but you can verify with php -m | grep openssl)
Decrypting the PDF: Only someone with the matching private key can decrypt the PDF. They can use tools like Adobe Acrobat or the following OpenSSL command:
```
openssl smime -decrypt -in encrypted_signed_contract.pdf -inkey private.key -out decrypted_contract.pdf
```
Permissions: If you want to allow limited actions (like printing) on the encrypted PDF, adjust the 3rd parameter of setEncryption() with TCPDF's permission constants (e.g., TCPDF_PERMISSION_PRINT)

Let me know if you hit any snags—happy to help work through specific issues!

内容的提问来源于stack exchange，提问作者Jonathon

Laravel 5.6与TCPDF公钥加密实现求助（PKI新手）

Replace AES Password Encryption with Public Key Encryption #

Replace AES Password Encryption with Public Key Encryption