How to Implement Electronic Signatures and Contract Management in PHP

How to Implement Electronic Signatures and Contract Management in PHP

In the digital age, traditional paper contracts no longer meet the demands for speed, security, and convenience. Electronic signature and contract management functionalities address these challenges, helping businesses streamline processes and improve efficiency. This article will introduce how to implement these features in PHP, guiding you through the process of generating electronic signatures, signature verification, and contract management.

Implementing Electronic Signature Functionality

Generating Signature Images

In PHP, the GD library can be used to generate signature images easily. Here is an example code:

$signatureText = "John Doe";
$imageWidth = 200;
$imageHeight = 100;
$signatureImage = imagecreatetruecolor($imageWidth, $imageHeight);
$backgroundColor = imagecolorallocate($signatureImage, 255, 255, 255);
$textColor = imagecolorallocate($signatureImage, 0, 0, 0);
imagefill($signatureImage, 0, 0, $backgroundColor);
imagettftext($signatureImage, 20, 0, 10, 50, $textColor, "path/to/font.ttf", $signatureText);
imagepng($signatureImage, "path/to/signature.png");
imagedestroy($signatureImage);

In the code above, we first set the signature text, image width, and height. We then create a true-color image object and set the background and text colors. The `imagefill` method is used to fill the background, and the `imagettftext` method is used to write the signature text into the image. Finally, we use `imagepng` to save the image and `imagedestroy` to release the image resources.

Verifying the Signature

To ensure the authenticity of the signature, public and private keys can be used for encryption and decryption verification. Here is a code example:

$signature = "path/to/signature.png";
$publicKey = "path/to/public_key.pem";
$data = "Some data to sign";
$publicKeyResource = openssl_pkey_get_public(file_get_contents($publicKey));
$signatureData = base64_decode(file_get_contents($signature));
$result = openssl_verify($data, $signatureData, $publicKeyResource);
if ($result == 1) {
    echo "Signature verified!";
} else {
    echo "Signature verification failed!";
}
openssl_free_key($publicKeyResource);

In this code, we first specify the signature image path, public key path, and the data to verify. We use `openssl_pkey_get_public` to get the public key resource and `base64_decode` to decode the signature data. Then, we use `openssl_verify` to verify the data, and if the result is 1, the signature is valid.

Implementing Contract Management Functionality

Creating a Contract

Contract creation typically involves selecting a contract template and filling in contract details. Here is an example code:

$templateId = $_POST['template_id'];
$contractTitle = $_POST['title'];
$content = $_POST['content'];
// Save contract data to a database or other storage
echo "Contract created successfully!";

In this code, we use `$_POST` to get the selected contract template ID, title, and content. Then, we save the contract data to the database and return a success message.

Signing the Contract

Signing a contract requires verifying the signer's identity and signature before the contract can be signed. Here is the related code:

$contractId = $_GET['contract_id'];
$signature = $_FILES['signature'];
// Verify the signer's identity and signature
// Save the signing information to a database or other storage
echo "Contract signed successfully!";

In this code, we first use `$_GET` to get the contract ID and the uploaded signature file. Then, we perform identity and signature verification, and if the verification passes, we save the signing information.

Querying the Contract

The contract query functionality allows signers or other relevant parties to check the status and details of a contract. Here is the example code:

$contractId = $_GET['contract_id'];
// Query the contract information from the database or other storage
// Output the contract details
echo "Contract details:";

In this code, we use `$_GET` to get the contract ID, then query the contract details from the database and display them.

Conclusion

This article introduced how to implement electronic signatures and contract management using PHP. The electronic signature functionality includes generating signature images and verifying signatures, while the contract management functionality covers contract creation, signing, and querying. Implementing these features can greatly enhance efficiency and security, especially in modern enterprises.