75 lines
2.2 KiB
PHP
75 lines
2.2 KiB
PHP
<?php
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namespace hema\wechat;
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/**
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* 微信支付V3 - 报文解密
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*
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*/
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class AesUtil
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{
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/**
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* AES key
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* @var string
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*/
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private $aesKey; //ApiV3密钥
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private $error;
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const KEY_LENGTH_BYTE = 32;
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const AUTH_TAG_LENGTH_BYTE = 16;
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/**
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* 构造函数
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*/
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public function __construct($aesKey)
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{
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if (strlen($aesKey) != self::KEY_LENGTH_BYTE) {
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$this->error = '无效的ApiV3Key，长度应为32个字节';
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return false;
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}
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$this->aesKey = $aesKey;
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}
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/**
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* Decrypt AEAD_AES_256_GCM ciphertext
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*
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* @param string $associatedData AES GCM additional authentication data
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* @param string $nonceStr AES GCM nonce
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* @param string $ciphertext AES GCM cipher text
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*
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* @return string|bool Decrypted string on success or FALSE on failure
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*/
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public function decryptToString($associatedData, $nonceStr, $ciphertext)
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{
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$ciphertext = \base64_decode($ciphertext);
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if (strlen($ciphertext) <= self::AUTH_TAG_LENGTH_BYTE) {
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$this->error = '待解密报文不合法';
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return false;
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}
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// ext-sodium (default installed on >= PHP 7.2)
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if (function_exists('\sodium_crypto_aead_aes256gcm_is_available') && \sodium_crypto_aead_aes256gcm_is_available()) {
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return \sodium_crypto_aead_aes256gcm_decrypt($ciphertext, $associatedData, $nonceStr, $this->aesKey);
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}
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// ext-libsodium (need install libsodium-php 1.x via pecl)
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if (function_exists('\Sodium\crypto_aead_aes256gcm_is_available') && \Sodium\crypto_aead_aes256gcm_is_available()) {
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return \Sodium\crypto_aead_aes256gcm_decrypt($ciphertext, $associatedData, $nonceStr, $this->aesKey);
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}
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// openssl (PHP >= 7.1 support AEAD)
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if (PHP_VERSION_ID >= 70100 && in_array('aes-256-gcm', \openssl_get_cipher_methods())) {
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$ctext = substr($ciphertext, 0, -self::AUTH_TAG_LENGTH_BYTE);
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$authTag = substr($ciphertext, -self::AUTH_TAG_LENGTH_BYTE);
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return \openssl_decrypt($ctext, 'aes-256-gcm', $this->aesKey, \OPENSSL_RAW_DATA, $nonceStr,
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$authTag, $associatedData);
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}
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$this->error = 'AEAD_AES_256_GCM需要PHP 7.1以上或者安装libsodium-php';
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return false;
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}
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public function getError()
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{
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return $this->error;
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}
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}
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