C语言 ESP8266 AES 加密 - 解密

Question

我确定我做错了解码和解密，但我不知道到底是什么。

#include "AES.h"
#include "Base64.h"
AES aes;
// Our AES key. Note that is the same that is used on the Node-Js side but as hex bytes.
byte key[] = {0x7e, 0x4e, 0x42, 0x38, 0x43, 0x63, 0x4f, 0x4c, 0x23, 0x4a, 0x21, 0x48, 0x3f, 0x7c, 0x59, 0x72};
// The unitialized Initialization vector
byte iv[N_BLOCK] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
// Our message to encrypt. Static for this example.
String msg = "{"data":{"value":300}, "SEQN":700 , "msg":"IT WORKS!!" }";
uint8_t generate_random_unit8()
{
  uint8_t really_random = *(volatile uint8_t *)0x3FF20E44;
  return really_random;
}
// Generate a random initialization vector
void generate_iv(byte *vector)
{
  for (int i = 0; i < N_BLOCK; i++)
  {
    vector[i] = (byte)generate_random_unit8();
  }
}
void encrypt()
{
  char b64data[200];
  byte cipher[1000];
  byte iv[N_BLOCK];
  generate_iv(iv);
  base64_encode(b64data, (char *)iv, N_BLOCK);
  String IV_base64 = String(b64data);
  Serial.println(" IV b64: " + IV_base64);
  int b64len = base64_encode(b64data, (char *)msg.c_str(), msg.length());
  Serial.println(" The lenght is:  " + String(b64len));
  // Encrypt! With AES128, our key and IV, CBC and pkcs7 padding
  aes.do_aes_encrypt((byte *)b64data, b64len, cipher, key, 128, iv);
  Serial.println("Cipher size: " + String(aes.get_size()));
  base64_encode(b64data, (char *)cipher, aes.get_size());
  Serial.println("Encrypted data in base64: " + String(b64data));
  decrypt(b64data, IV_base64, aes.get_size());
}
void decrypt(String b64data, String IV_base64, int size)
{
  char data_decoded[200];
  char iv_decoded[200];
  byte out[200];
  char temp[200];
  b64data.toCharArray(temp, 200);
  base64_decode(data_decoded, temp, b64data.length());
  IV_base64.toCharArray(temp, 200);
  base64_decode(iv_decoded, temp, IV_base64.length());
  aes.do_aes_decrypt((byte *)data_decoded, size, out, key, 128, (byte *)iv_decoded);
  char message[msg.length()];
  base64_decode(message, (char *)out, b64data.length());
  printf("Out %s n", message);
}
void setup_aes()
{
  aes.set_key(key, sizeof(key)); // Get the globally defined key
}
void setup()
{
  Serial.begin(115200);
}
void loop()
{
  encrypt();
  delay(1000);
}

解码的消息应{"data":{"value":300}, "SEQN":700 , "msg":"IT WORKS!!" 。但是我越来越{"data":{"value":300}, "SEQN":700 , "msg":"IT WORKS!!" }�������������������������.我会假设字符长度不正确？

Answer 1

如果编码，则应使用 \0 完成字符串，因此在解码数据中，\0 也存在，并且 printf 可以正确以 \0 结尾。

修复将是 int b64len = base64_encode(b64data, (char *)msg.c_str(), msg.length()+1);这可确保包含隐式 \0 字节。编译器会自动将其添加到 msg 字符串中。

试试吧！

Answer 2

我最近自己也遇到了同样的问题，我花了几个小时试图解决这个问题。伊万诺夫，你对编码数据的长度有一个很好的观点。主要问题基本上是当AES加密功能创建额外的填充并且解密功能无法删除它时。

这与字符串的空终止或缺少终止符的事实无关。实际上，只需从解密字符串中省略最后 5 个填充即可解决问题。

编辑 这实际上不仅仅是从末尾省略 5 个字符。由于我发现乱码或填充的数量因原始 JSON 的长度而异，因此通过检测 JSON 字符串的末尾来修剪字符串更有意义。

我正在提供我的（更新的）工作代码以供参考。我希望这对任何也有这个问题的人有所帮助！祝你的项目好运！

#include "AES.h"
#include "Base64.h"
AES aes;
// Our AES key. Same in NodeJS but in hex bytes
byte key[] = { 0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C };
// The unitialized Initialization vector (16-bit)
byte iv[N_BLOCK] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
// NodeMCU side raw message
String msg = "{"x":10, "y":20, "z":30 "lamp_stat":"ON  This is a sentence. Testing testing testing"}";
uint8_t generate_random_unit8()
{
  uint8_t really_random = *(volatile uint8_t *)0x3FF20E44;
  return really_random;
}
// Generate a random initialization vector
void generate_iv(byte *vector)
{
  for (int i = 0; i < N_BLOCK; i++)
  {
    vector[i] = (byte)generate_random_unit8();
  }
}
void encrypt()
{
  char b64data[200];
  byte cipher[1000];
  byte iv[N_BLOCK];
  generate_iv(iv);
  base64_encode(b64data, (char *)iv, N_BLOCK);
  String IV_base64 = String(b64data);
  Serial.println(" IV b64: " + IV_base64);
  int b64len = base64_encode(b64data, (char *)msg.c_str(), msg.length());
  Serial.println(" The lenght is:  " + String(b64len));
  // Encrypt! With AES128, our key and IV, CBC and pkcs7 padding
  aes.do_aes_encrypt((byte *)b64data, b64len, cipher, key, 128, iv);
  Serial.println("Cipher size: " + String(aes.get_size()));
  base64_encode(b64data, (char *)cipher, aes.get_size());
  Serial.println("Encrypted data in base64: " + String(b64data));
  //decrypt(b64data, IV_base64, aes.get_size());
}
void decrypt(String b64data, String IV_base64, int lsize)
{
  char data_decoded[300];
  char iv_decoded[300];
  byte out[300];
  char temp[300];
  b64data.toCharArray(temp, 300);
  base64_decode(data_decoded, temp, b64data.length());
  IV_base64.toCharArray(temp, 300);
  base64_decode(iv_decoded, temp, IV_base64.length());
  aes.do_aes_decrypt((byte *)data_decoded, lsize, out, key, 128, (byte *)iv_decoded);
  char message[msg.length()];
  base64_decode(message, (char *)out, aes.get_size());
  for (int i = 0; i < aes.get_size(); i++)
  {
    char curChar = (char)message[i];
    if (curChar != '}')
      temp[i] = curChar;
    else
    {
      temp[i] = curChar;
      temp[i+1] = '';
      break;
    }
  }
  String result = String((char *)temp);
  Serial.println(result);
}
void setup_aes()
{
  aes.set_key(key, sizeof(key)); // Get the globally defined key
}
void setup()
{
  Serial.begin(115200);
}
void loop()
{
  encrypt();
  decrypt("ipYk12VCYyD+aJ7KL7lO8L5zOq71XvsLzp650gKBFgQor7GHs98QpQSjQOZdhCwggq2Ehf4nVNwTeK3VjtqMVJRGBw9YViARXCTOGqctjFc=", "+eNzSlRRPi0YZhrp5ctpnA==", 83);
  delay(8000);
}

Answer 3

我终于发现了问题所在。

base64_decode(message, (char *)out, b64data.length());

应该是

base64_decode(message, (char *)out, 75); - 编码数据的长度 - 1

至少 PoC 有效。