Question

使用3DES解密文件时遇到问题。除了文件末尾的小符号外，文件保持完全相同。我尝试更改文件读取类型，但也无法正常工作。是否可能是因为我改变了IV？

这是我的加密php代码：

$log = fopen($datalog, 'a') or die("can't open file");

//create a random IV to use with CBC encoding
$iv_size = mcrypt_get_iv_size(MCRYPT_3DES, MCRYPT_MODE_CBC);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
echo " ";
echo "IP: ";
echo $address;
$enc_add = mcrypt_encrypt(MCRYPT_3DES, $key, $address, MCRYPT_MODE_CBC, $iv); 
$add64 = base64_encode($enc_add);
fwrite ($log, $add64);
echo " ";
echo "INFO: ";
echo $info;
$enc_info = mcrypt_encrypt(MCRYPT_3DES, $key, $info, MCRYPT_MODE_CBC, $iv); 
$info64 = base64_encode($enc_info);
fwrite ($log, $info64);
echo " ";
echo "TIMESTAMP: ";
echo $datetimeStamp;
$enc_ts = mcrypt_encrypt(MCRYPT_3DES, $key, $datetimeStamp, MCRYPT_MODE_CBC, $iv); 
$ts64 = base64_encode($enc_ts);
fwrite ($log, $ts64);
echo " ";
echo "COUNTRY: ";
echo $country;
$enc_co = mcrypt_encrypt(MCRYPT_3DES, $key, $country, MCRYPT_MODE_CBC, $iv); 
$country64 = base64_encode($enc_co);
fwrite ($log, $country64);
echo " ";
echo "LATITUDE: ";
echo $lat;
$enc_lat = mcrypt_encrypt(MCRYPT_3DES, $key, $lat, MCRYPT_MODE_CBC, $iv); 
$lat64 = base64_encode($enc_lat);
fwrite ($log, $lat64);
echo " ";
echo "LONGITUDE: ";
echo $long;
$enc_long = mcrypt_encrypt(MCRYPT_3DES, $key, $long, MCRYPT_MODE_CBC, $iv); 
$long64 = base64_encode($enc_long);
fwrite ($log, $long64);

    //data related to ping
$enc_data = mcrypt_encrypt(MCRYPT_3DES, $key, $dataForIP, MCRYPT_MODE_CBC, $iv); 
$data64 = base64_encode($enc_data);
fwrite ($log, $data64);

fclose($log);

}

以下是我的解密代码：

if ($_POST['submit']) {
    $file = $_POST["filename"];
    $key = $_POST["key"];
    $file_beingVerified = fopen($file, 'a+') or die ("can't open file");

    $iv_size = mcrypt_get_iv_size(MCRYPT_3DES, MCRYPT_MODE_CBC);

    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
    while (!feof($file_beingVerified)) {
        $str = fgets($file_beingVerified);

        $reversed = base64_decode($str);
        $enc_add = mcrypt_decrypt(MCRYPT_3DES, $key, $reversed, MCRYPT_MODE_CBC, $iv);

        fwrite($file_beingVerified, $enc_add);
    }
    fclose($file_beingVerified);
}

Answer 1

代码中存在多个问题：

same IV需要用于加密和解密。

该文件应如下所示：

$str = '';
while (!feof($fileBeingVerified)) {
    $str .= fread($fileBeingVerified, filesize($file));
}

将加密数据写入文件时，请使用“w”模式打开它，以确保该文件不包含其他内容。
读取文件时，请使用“r”模式将其打开，将文件指针放在文件的开头。
必须删除填充：$enc_add = rtrim($enc_add, "\0");

请参阅此示例以供参考：

<?php
$file = '/tmp/data';
$log = fopen($file, 'w') or die("can't open file");

$data = 'hello world';
$ivSize = mcrypt_get_iv_size(MCRYPT_3DES, MCRYPT_MODE_CBC);
$iv = mcrypt_create_iv($ivSize, MCRYPT_RAND);
$key = 'my-secure-key';

$encData = mcrypt_encrypt(MCRYPT_3DES, $key, $data, MCRYPT_MODE_CBC, $iv);
$data64 = base64_encode($encData);
fwrite($log, $data64);


$fileBeingVerified = fopen($file, 'r') or die ("can't open file");

$str = '';
while (!feof($fileBeingVerified)) {
    $str .= fread($fileBeingVerified, filesize($file));
}


$reversed = base64_decode($str);
$enc_add = mcrypt_decrypt(MCRYPT_3DES, $key, $reversed, MCRYPT_MODE_CBC, $iv);

$fileBeingVerified = fopen($file, 'w') or die ("can't open file");
fwrite($fileBeingVerified, $enc_add);
fclose($fileBeingVerified);

解密文件不能正常工作PHP

1 个答案: