function sign($data) {
 //讀取私鑰文件
 $priKey = file_get_contents('key/rsa_private_key.pem');
 
 //轉(zhuǎn)換為openssl密鑰，必須是沒有經(jīng)過pkcs8轉(zhuǎn)換的私鑰
 $res = openssl_get_privatekey($priKey);
 
 //調(diào)用openssl內(nèi)置簽名方法，生成簽名$sign
 openssl_sign($data, $sign, $res);
 
 //釋放資源
 openssl_free_key($res);
 
 return $sign;
}

function verify($data, $sign) {
 //讀取支付寶公鑰文件
 $pubKey = file_get_contents('key/alipay_public_key.pem');
 
 //轉(zhuǎn)換為openssl格式密鑰
 $res = openssl_get_publickey($pubKey);
 
 //調(diào)用openssl內(nèi)置方法驗簽，返回bool值
 $result = (bool)openssl_verify($data, $sign, $res);
 
 //釋放資源
 openssl_free_key($res);
 
 return $result;

function decrypt($content) {
 
 //讀取商戶私鑰
 $priKey = file_get_contents('key/rsa_private_key.pem');
 
 //轉(zhuǎn)換為openssl密鑰，必須是沒有經(jīng)過pkcs8轉(zhuǎn)換的私鑰
 $res = openssl_get_privatekey($priKey);
 
 //聲明明文字符串變量
 $result = '';
 
 //循環(huán)按照128位解密
 for($i = 0; $i < strlen($content)/128; $i++ ) {
 $data = substr($content, $i * 128, 128);
  
 //拆分開長度為128的字符串片段通過私鑰進(jìn)行解密，返回$decrypt解析后的明文
 openssl_private_decrypt($data, $decrypt, $res);
 
 //明文片段拼接
 $result .= $decrypt;
 }
 
 //釋放資源
 openssl_free_key($res);
 
 //返回明文
 return $result;
}