How to Encrypt in Flutter and Decrypt in ESP8266

gistfile1.txt

Encrypt in Flutter

String encryptDecrypt(String input) {
    var key = ['KCQ']; //Can be any chars, and any size array
    var output = [];
    
    for(var i = 0; i < input.length; i++) {
      var charCode = input.codeUnitAt(i) ^ key[i % key.length].codeUnitAt(0);
      output.add(new String.fromCharCode(charCode));
    }
    
    return output.join("");
  }


Decrypt in ESP8266
  
 String request = ""; 
 char * key = "KCQ";
 char *p = const_cast<char*>(request.c_str());
  
char *xor(char *string, const char *key)
{
    char *s = string;
    size_t length = strlen(key), i = 0;
    while (*s) {
            *s++ ^= key[i++ % length];
    }
    return string;
}