ESP8266 AES加密-解密

Question

我确信我做错了解码和解密，但我不知道具体是什么。

#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);
}

解码后的消息应该是{"data":{"value":300}, "SEQN":700 , "msg":"IT WORKS!!"。然而，我得到了{"data":{"value":300}, "SEQN":700 , "msg":"IT WORKS!!" }�������������������������。我会假设字符长度不正确？

Answer 1

如果你编码，你应该用\0结束字符串，所以在解码的数据中，\0也在那里，printf可以正确地在\0结束。

修复方法是int b64len = base64_encode(b64data, (char *)msg.c_str(), msg.length()+1);，这样可以确保包含隐式\0字节。编译器自动将其添加到msg字符串中。

试试看！

Answer 2

最近我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。Ivanov，关于编码数据的长度，你有一个很好的观点。主要的问题是，当AES加密功能创建额外的填充而解密功能不能移除它时。

这与字符串的null终止或缺少终止符的事实无关。这个问题实际上是通过简单地省略解密字符串中的最后5个填充来解决的。

编辑这实际上不仅仅是省略了结尾的5个字符。由于我发现乱码或填充的数量取决于原始JSON的长度，因此通过检测JSON字符串的末尾来修剪字符串更有意义。

我提供我的(更新)工作代码作为参考。我希望这篇文章能帮助那些也有这个问题的人！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] = '\0';
      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

我终于找到问题所在了。

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

应该是

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

至少PoC可以工作。