--- /dev/null
+/*****************************************************************************
+ * This file is part of iClassCipher. It is a reconstructon of the cipher engine
+ * used in iClass, and RFID techology.
+ *
+ * The implementation is based on the work performed by
+ * Flavio D. Garcia, Gerhard de Koning Gans, Roel Verdult and
+ * Milosch Meriac in the paper "Dismantling IClass".
+ *
+ * Copyright (C) 2014 Martin Holst Swende
+ *
+ * This is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with IClassCipher. If not, see <http://www.gnu.org/licenses/>.
+ ****************************************************************************/
+
+#ifndef CIPHER_H
+#define CIPHER_H
+#include <stdint.h>
+
+/**
+* Definition 1 (Cipher state). A cipher state of iClass s is an element of F 40/2
+* consisting of the following four components:
+* 1. the left register l = (l 0 . . . l 7 ) ∈ F 8/2 ;
+* 2. the right register r = (r 0 . . . r 7 ) ∈ F 8/2 ;
+* 3. the top register t = (t 0 . . . t 15 ) ∈ F 16/2 .
+* 4. the bottom register b = (b 0 . . . b 7 ) ∈ F 8/2 .
+**/
+typedef struct {
+ uint8_t l;
+ uint8_t r;
+ uint8_t b;
+ uint16_t t;
+} State;
+
+void printarr(char * name, uint8_t* arr, int len);
+int calc_iclass_mac(uint8_t *cc_nr_p, int length, uint8_t *div_key_p, uint8_t *mac);
+
+#endif // CIPHER_H