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vendor/overtrue/wechat/src/Kernel/Encryptor.php

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+<?php
+
+/*
+ * This file is part of the overtrue/wechat.
+ *
+ * (c) overtrue <i@overtrue.me>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace EasyWeChat\Kernel;
+
+use EasyWeChat\Kernel\Exceptions\RuntimeException;
+use EasyWeChat\Kernel\Support\AES;
+use EasyWeChat\Kernel\Support\XML;
+use Throwable;
+use function EasyWeChat\Kernel\Support\str_random;
+
+/**
+ * Class Encryptor.
+ *
+ * @author overtrue <i@overtrue.me>
+ */
+class Encryptor
+{
+    public const ERROR_INVALID_SIGNATURE = -40001; // Signature verification failed
+    public const ERROR_PARSE_XML = -40002; // Parse XML failed
+    public const ERROR_CALC_SIGNATURE = -40003; // Calculating the signature failed
+    public const ERROR_INVALID_AES_KEY = -40004; // Invalid AESKey
+    public const ERROR_INVALID_APP_ID = -40005; // Check AppID failed
+    public const ERROR_ENCRYPT_AES = -40006; // AES EncryptionInterface failed
+    public const ERROR_DECRYPT_AES = -40007; // AES decryption failed
+    public const ERROR_INVALID_XML = -40008; // Invalid XML
+    public const ERROR_BASE64_ENCODE = -40009; // Base64 encoding failed
+    public const ERROR_BASE64_DECODE = -40010; // Base64 decoding failed
+    public const ERROR_XML_BUILD = -40011; // XML build failed
+    public const ILLEGAL_BUFFER = -41003; // Illegal buffer
+
+    /**
+     * App id.
+     *
+     * @var string
+     */
+    protected $appId;
+
+    /**
+     * App token.
+     *
+     * @var string
+     */
+    protected $token;
+
+    /**
+     * @var string
+     */
+    protected $aesKey;
+
+    /**
+     * Block size.
+     *
+     * @var int
+     */
+    protected $blockSize = 32;
+
+    /**
+     * Constructor.
+     */
+    public function __construct(string $appId, string $token = null, string $aesKey = null)
+    {
+        $this->appId = $appId;
+        $this->token = $token;
+        $this->aesKey = base64_decode($aesKey.'=', true);
+    }
+
+    /**
+     * Get the app token.
+     */
+    public function getToken(): string
+    {
+        return $this->token;
+    }
+
+    /**
+     * Encrypt the message and return XML.
+     *
+     * @param string $xml
+     * @param string $nonce
+     * @param int    $timestamp
+     *
+     * @throws \EasyWeChat\Kernel\Exceptions\RuntimeException
+     */
+    public function encrypt($xml, $nonce = null, $timestamp = null): string
+    {
+        try {
+            $xml = $this->pkcs7Pad(str_random(16).pack('N', strlen($xml)).$xml.$this->appId, $this->blockSize);
+
+            $encrypted = base64_encode(AES::encrypt(
+                $xml,
+                $this->aesKey,
+                substr($this->aesKey, 0, 16),
+                OPENSSL_NO_PADDING
+            ));
+            // @codeCoverageIgnoreStart
+        } catch (Throwable $e) {
+            throw new RuntimeException($e->getMessage(), self::ERROR_ENCRYPT_AES);
+        }
+        // @codeCoverageIgnoreEnd
+
+        !is_null($nonce) || $nonce = substr($this->appId, 0, 10);
+        !is_null($timestamp) || $timestamp = time();
+
+        $response = [
+            'Encrypt' => $encrypted,
+            'MsgSignature' => $this->signature($this->token, $timestamp, $nonce, $encrypted),
+            'TimeStamp' => $timestamp,
+            'Nonce' => $nonce,
+        ];
+
+        //生成响应xml
+        return XML::build($response);
+    }
+
+    /**
+     * Decrypt message.
+     *
+     * @param string $content
+     * @param string $msgSignature
+     * @param string $nonce
+     * @param string $timestamp
+     *
+     * @throws \EasyWeChat\Kernel\Exceptions\RuntimeException
+     */
+    public function decrypt($content, $msgSignature, $nonce, $timestamp): string
+    {
+        $signature = $this->signature($this->token, $timestamp, $nonce, $content);
+
+        if ($signature !== $msgSignature) {
+            throw new RuntimeException('Invalid Signature.', self::ERROR_INVALID_SIGNATURE);
+        }
+
+        $decrypted = AES::decrypt(
+            base64_decode($content, true),
+            $this->aesKey,
+            substr($this->aesKey, 0, 16),
+            OPENSSL_NO_PADDING
+        );
+        $result = $this->pkcs7Unpad($decrypted);
+        $content = substr($result, 16, strlen($result));
+        $contentLen = unpack('N', substr($content, 0, 4))[1];
+
+        if (trim(substr($content, $contentLen + 4)) !== $this->appId) {
+            throw new RuntimeException('Invalid appId.', self::ERROR_INVALID_APP_ID);
+        }
+
+        return substr($content, 4, $contentLen);
+    }
+
+    /**
+     * Get SHA1.
+     */
+    public function signature(): string
+    {
+        $array = func_get_args();
+        sort($array, SORT_STRING);
+
+        return sha1(implode($array));
+    }
+
+    /**
+     * PKCS#7 pad.
+     *
+     * @throws \EasyWeChat\Kernel\Exceptions\RuntimeException
+     */
+    public function pkcs7Pad(string $text, int $blockSize): string
+    {
+        if ($blockSize > 256) {
+            throw new RuntimeException('$blockSize may not be more than 256');
+        }
+        $padding = $blockSize - (strlen($text) % $blockSize);
+        $pattern = chr($padding);
+
+        return $text.str_repeat($pattern, $padding);
+    }
+
+    /**
+     * PKCS#7 unpad.
+     */
+    public function pkcs7Unpad(string $text): string
+    {
+        $pad = ord(substr($text, -1));
+        if ($pad < 1 || $pad > $this->blockSize) {
+            $pad = 0;
+        }
+
+        return substr($text, 0, (strlen($text) - $pad));
+    }
+}