version2/src/C/Crypto.cpp

   1 #include "Crypto.h"
   2 #include "pbkdf2-sha256.h"
   3
   4 AESKey::AESKey(Array<char> *password, Array<char> *salt, int iterationCount, int keyLength) {
   5
   6         // Check if we get the same salt and password from EEPROM---create new ones otherwise
   7         char saltBuffer[SALT_LEN], pwdBuffer[PWD_LEN], keyBuffer[KEY_LEN];
   8         EEPROM.get(ADDR_SALT, saltBuffer);
   9         Array<char> * storedSalt = new Array<char>(saltBuffer, SALT_LEN);
  10         EEPROM.get(ADDR_PWD, pwdBuffer);
  11         Array<char> * storedPwd = new Array<char>(pwdBuffer, PWD_LEN);
  12         if (storedSalt->equals(salt) && storedPwd->equals(password)) { // Take key from EEPROM if match
  13                 EEPROM.get(ADDR_KEY, keyBuffer);
  14                 key = new Array<char>(keyBuffer, KEY_LEN);
  15                 delay(2000);    // Delay for sensor
  16         } else {        // Generate a new key if not match
  17                 key = new Array<char>(keyLength / 8);
  18                 PKCS5_PBKDF2_HMAC((unsigned char *) password->internalArray(), password->length(),
  19                                                                                         (unsigned char *) salt->internalArray(), salt->length(),
  20                                                                                         iterationCount, keyLength / 8, (unsigned char *) key->internalArray());
  21                 // Store new salt and password into EEPROM---write all at once adjacently
  22                 char buffer[SALT_LEN + PWD_LEN + KEY_LEN];
  23                 memcpy(buffer + SALT_OFFSET, (unsigned char *) salt->internalArray(), SALT_LEN);
  24                 memcpy(buffer + PWD_OFFSET, (unsigned char *) password->internalArray(), PWD_LEN);
  25                 memcpy(buffer + KEY_OFFSET, (unsigned char *) key->internalArray(), KEY_LEN);
  26                 EEPROM.put(ADDR_SALT, buffer);
  27         }
  28         aes_key_setup((BYTE *)key->internalArray(), key_schedule, keyLength);
  29 }
  30
  31 AESKey::~AESKey() {
  32         bzero(key->internalArray(), key->length());
  33         delete key;
  34         bzero(key_schedule, sizeof(key_schedule));
  35 }
  36
  37 WORD *AESKey::getKeySchedule() {
  38         return (WORD *) &key_schedule;
  39 }
  40
  41 Array<char> *AESKey::getKey() {
  42         return key;
  43 }