Crypto.h

00001 /* ______                              _
00002   / _____)             _              | |
00003  ( (____  _____ ____ _| |_ _____  ____| |__
00004   \____ \| ___ |    (_   _) ___ |/ ___)  _ \
00005   _____) ) ____| | | || |_| ____( (___| | | |
00006  (______/|_____)_|_|_| \__)_____)\____)_| |_|
00007  (C)2013 Semtech
00008 
00009  Description: LoRa MAC layer implementation
00010 
00011  License: Revised BSD License, see LICENSE.TXT file include in the project
00012 
00013  Maintainer: Miguel Luis and Gregory Cristian
00014  */
00015 #ifndef __LORA_CRYPTO_H__
00016 #define __LORA_CRYPTO_H__
00017 
00018 #include "casado/aes.h"
00019 #include "gladman/cmac.h"
00020 #include <cstring>
00021 #include <inttypes.h>
00022 
00023 namespace lora {
00024 
00025     class Crypto
00026     {
00027         public:
00028             Crypto(void);
00029 
00030             /*!
00031              * Computes the LoRaMAC frame MIC field
00032              *
00033              * \param [IN]  buffer          Data buffer
00034              * \param [IN]  size            Data buffer size
00035              * \param [IN]  key             AES key to be used
00036              * \param [IN]  address         Frame address
00037              * \param [IN]  dir             Frame direction [0: uplink, 1: downlink, 2:peer]
00038              * \param [IN]  sequenceCounter Frame sequence counter
00039              * \param [OUT] mic             Computed MIC field
00040              */
00041             void ComputeMic(uint8_t *buffer, uint16_t size, uint8_t *key, uint32_t address, uint8_t dir, uint32_t sequenceCounter, uint32_t *mic);
00042 
00043             /*!
00044              * Computes the LoRaMAC payload encryption
00045              *
00046              * \param [IN]  buffer          Data buffer
00047              * \param [IN]  size            Data buffer size
00048              * \param [IN]  key             AES key to be used
00049              * \param [IN]  address         Frame address
00050              * \param [IN]  dir             Frame direction [0: uplink, 1: downlink, 2:peer]
00051              * \param [IN]  sequenceCounter Frame sequence counter
00052              * \param [OUT] encBuffer       Encrypted buffer
00053              */
00054             void PayloadEncrypt(const uint8_t *buffer, uint16_t size, uint8_t *key, uint32_t address, uint8_t dir, uint32_t sequenceCounter, uint8_t *encBuffer);
00055 
00056             /*!
00057              * Computes the LoRaMAC payload decryption
00058              *
00059              * \param [IN]  buffer          Data buffer
00060              * \param [IN]  size            Data buffer size
00061              * \param [IN]  key             AES key to be used
00062              * \param [IN]  address         Frame address
00063              * \param [IN]  dir             Frame direction [0: uplink, 1: downlink, 2:peer]
00064              * \param [IN]  sequenceCounter Frame sequence counter
00065              * \param [OUT] decBuffer       Decrypted buffer
00066              */
00067             void PayloadDecrypt(uint8_t *buffer, uint16_t size, uint8_t *key, uint32_t address, uint8_t dir, uint32_t sequenceCounter, uint8_t *decBuffer);
00068 
00069             /*!
00070              * Computes the LoRaMAC Join Request frame MIC field
00071              *
00072              * \param [IN]  buffer          Data buffer
00073              * \param [IN]  size            Data buffer size
00074              * \param [IN]  key             AES key to be used
00075              * \param [OUT] mic             Computed MIC field
00076              */
00077             void JoinComputeMic(const uint8_t *buffer, uint16_t size, const uint8_t *key, uint32_t *mic);
00078 
00079             /*!
00080              * Computes the LoRaMAC join frame decryption
00081              *
00082              * \param [IN]  buffer          Data buffer
00083              * \param [IN]  size            Data buffer size
00084              * \param [IN]  key             AES key to be used
00085              * \param [OUT] decBuffer       Decrypted buffer
00086              */
00087             void JoinDecrypt(uint8_t *buffer, uint16_t size, uint8_t *key, uint8_t *decBuffer);
00088 
00089             /*!
00090              * Computes the LoRaMAC join frame decryption
00091              *
00092              * \param [IN]  key             AES key to be used
00093              * \param [IN]  appNonce        Application nonce
00094              * \param [IN]  devNonce        Device nonce
00095              * \param [OUT] nwkSKey         Network session key
00096              * \param [OUT] appSKey         Application session key
00097              */
00098             void DeriveSessionKeys(uint8_t *key, uint8_t *appNonce, uint8_t *netID, uint16_t devNonce, uint8_t *nwkSKey, uint8_t *appSKey);
00099 
00100             /*!
00101              * Compute ping slot for current beacon frame
00102              * \param [IN]  beaconTime     Time of current beacon
00103              * \param [IN]  devAddr        Device Address
00104              * \param [IN]  period         Period of downlink
00105              * \return current pinslot
00106              */
00107             uint32_t ComputePingSlot(uint32_t beaconTime, uint32_t devAddr, uint32_t period);
00108 
00109             /*!
00110              * Helper to copy mic bytes onto buffer
00111              * \param [IN]  mic         integer mic value
00112              * \param [IN]  buff        location to copy to
00113              */
00114             void CopyMicToArray(uint32_t mic, uint8_t* buff);
00115 
00116             void DeriveMcKEKey(uint8_t *mcKEKey, uint8_t *appKey, uint8_t *EUI);
00117             
00118             void DeriveMcKey(uint8_t *mcKey, uint8_t *mcKeyEncrypt, uint8_t *mcKEKey);
00119 
00120             void DeriveMcSessionKeys(uint8_t *mcAppKey, uint8_t *mcNetKey, uint8_t *mcKey, uint8_t *mcAddr);
00121 
00122         private:
00123             /*!
00124              * MIC field computation initial data
00125              */
00126             uint8_t MicBlockB0[16];
00127 
00128             /*!
00129              * Contains the computed MIC field.
00130              *
00131              * \remark Only the 4 first bytes are used
00132              */
00133             uint8_t Mic[16];
00134 
00135             /*!
00136              * Encryption aBlock and sBlock
00137              */
00138             uint8_t aBlock[16];
00139             uint8_t sBlock[16];
00140 
00141             /*!
00142              * AES computation context variable
00143              */
00144             aes_context AesContext;
00145 
00146             /*!
00147              * CMAC computation context variable
00148              */
00149             AES_CMAC_CTX AesCmacCtx[1];
00150     };
00151 
00152 }
00153 #endif // __LORAMAC_CRYPTO_H__