PHP：如何加密一个文件中的数据，然后在另一个文件中解密？

Question

我正在尝试制作一个人们可以聊天的程序，并且我想加密正在发送的消息。为此我有 2 个脚本，一个是 sendtext.php，另一个是 getchat.php。

所以我的问题是如何加密在一个文件中发送的文本，然后解密将在另一个文件中发送回的消息。

到目前为止，我的加密工作正常，但我不知道如何在其他文件中解密。 此外，如果您知道一种更安全的方法，我们将不胜感激。

sendtext.php

    $username = $_POST["name"];
    $text = $_POST["message"];

    $key = openssl_random_pseudo_bytes(32, $cstrong);
    $cipher = "aes-128-gcm";

    if (in_array($cipher, openssl_get_cipher_methods()))
    {
        $ivlen = openssl_cipher_iv_length($cipher);
        $iv = openssl_random_pseudo_bytes($ivlen);
        $ciphertext = openssl_encrypt($text, $cipher, $key, $options=0, $iv, $tag);

        echo "Encrytped: " . $ciphertext;

        //store $cipher, $iv, and $tag for decryption later
        //$original_text = openssl_decrypt($ciphertext, $cipher, $key, $options=0, $iv, $tag);
        //echo $original_text."\n";
    }

    //Add text to the table
    $inserttextquery = "INSERT INTO ".$username." (username, message) 
                        VALUES ('$username', '$ciphertext');";
    mysqli_query($con, $inserttextquery) or die("#: send text failed");

getchat.php

$username = $_POST["name"];

    $sql = "SELECT username, message FROM ".$username."";
    $result = $con->query($sql);

    if ($result->num_rows > 0)
    {
        // output data of each row
        while($row = $result->fetch_assoc()) {
            echo $row["username"] . "\t" . $row["message"] . "\t";
        }
    } 

Answer 1

我前段时间写了这个加密/解密类：

<?php
class Cryptography
{
    private static $secret_key = 'gsdgsg423b523b5432bjbjm24vbjn2hv';
    const CIPHER_16 = 'AES-128-CBC';
    const CIPHER_32 = 'AES-256-CBC';
    public static function encrypt($str, $cl = 32)
    {
        return static::encyptedDecypted('encrypt', $str, $cl);
    }
    public static function decrypt($str, $cl = 32)
    {
        return static::encyptedDecypted('decrypt', $str, $cl);
    }
    public static function encyptedDecypted($action, $str, $cl)
    {
        $cl = (int) $cl;
        if ($cl === 16) {
            $cipher = static::CIPHER_16;
            $length = 16;
        } elseif ($cl === 32) {
            $cipher = static::CIPHER_32;
            $length = 32;
        } else {
            throw new Exception('Error Processing Request', 1);
        }
        $iv = $iv = substr(hash('sha256', static:: $secret_key), 0, 16);
        $key = hash('sha512', static::$secret_key);
        if ($action == 'encrypt') {
            $output = openssl_encrypt($str, $cipher, $key, 0, $iv);
            $output = base64_encode($output);
            $output = static::securesalts($length).$output.static::securesalts($length);
        } elseif ($action == 'decrypt') {
            $str = $text = substr($str, $length, -$length);
            $output = openssl_decrypt(base64_decode($str), $cipher, $key, 0, $iv);
        }
        return $output;
    }
    private static function securesalts($length)
    {
        if (is_int($length) && $length >= 5) {
            $chars = array_merge(range(0, 9), range('a', 'z'), range('A', 'Z'));
            $stringlength = count($chars); //Used Count because its array now
            $randomString = '';
            for ($i = 0; $i < $length; $i++) {
                $randomString .= $chars[rand(0, $stringlength - 1)];
            }
            return $randomString;
        } else {
            return false;
        }
    }
}

像这样使用它：

$str = "Simple String";

//for encryption
$encrypted = Cryptography::encrypt($str);

//for decryption
$decrypted = Cryptography::decrypt($encrypted);

别忘了更改$secret_key ;)