PHP实现RSA非对称加密技术

require_once('Crypt/RSA.php');

$rsa = new Crypt_RSA();
$rsa->setPublicKeyFormat(CRYPT_RSA_PUBLIC_FORMAT_PKCS1);
$rsa->setPrivateKeyFormat(CRYPT_RSA_PRIVATE_FORMAT_PKCS1);
$keys = $rsa->createKey();
file_put_contents('public_key.pem', $keys['publickey']);
file_put_contents('private_key.pem', $keys['privatekey']);

$data = 'hello, world';
$rsa = new Crypt_RSA();
$rsa->loadKey(file_get_contents('public_key.pem'));
$ciphertext = $rsa->encrypt($data);

$rsa = new Crypt_RSA();
$rsa->loadKey(file_get_contents('private_key.pem'));
$plaintext = $rsa->decrypt($ciphertext);

$config = array(
    "digest_alg" => "sha512",
    "private_key_bits" => 2048,
    "private_key_type" => OPENSSL_KEYTYPE_RSA,
);
$private_key = openssl_pkey_new($config);
openssl_pkey_export_to_file($private_key, "private.key");

$public_key = openssl_pkey_get_details($private_key);
$public_key = $public_key["key"];
file_put_contents("public.key", $public_key);

$data = 'hello, world';
openssl_public_encrypt($data, $ciphertext, $public_key);

openssl_private_decrypt($ciphertext, $plaintext, $private_key);