diff --git a/src/RadioLib.h b/src/RadioLib.h index b8a36385..b7df08d9 100644 --- a/src/RadioLib.h +++ b/src/RadioLib.h @@ -112,6 +112,7 @@ // utilities #include "utils/CRC.h" +#include "utils/Cryptography.h" // only create Radio class when using RadioShield #if defined(RADIOLIB_RADIOSHIELD) diff --git a/src/utils/Cryptography.cpp b/src/utils/Cryptography.cpp new file mode 100644 index 00000000..1339c3bb --- /dev/null +++ b/src/utils/Cryptography.cpp @@ -0,0 +1,294 @@ +#include "Cryptography.h" + +#include + +RadioLibAES128::RadioLibAES128() { + +} + +void RadioLibAES128::init(uint8_t* key) { + this->keyPtr = key; + this->keyExpansion(this->roundKey, key); +} + +size_t RadioLibAES128::encryptECB(uint8_t* in, size_t len, uint8_t* out) { + size_t num_blocks = len / RADIOLIB_AES128_BLOCK_SIZE; + if(len % RADIOLIB_AES128_BLOCK_SIZE) { + num_blocks++; + } + + memset(out, 0x00, RADIOLIB_AES128_BLOCK_SIZE * num_blocks); + memcpy(out, in, len); + + for(size_t i = 0; i < num_blocks; i++) { + this->cipher((state_t*)(out + (RADIOLIB_AES128_BLOCK_SIZE * i)), this->roundKey); + } + + return(num_blocks*RADIOLIB_AES128_BLOCK_SIZE); +} + +size_t RadioLibAES128::decryptECB(uint8_t* in, size_t len, uint8_t* out) { + size_t num_blocks = len / RADIOLIB_AES128_BLOCK_SIZE; + if(len % RADIOLIB_AES128_BLOCK_SIZE) { + num_blocks++; + } + + memset(out, 0x00, RADIOLIB_AES128_BLOCK_SIZE * num_blocks); + memcpy(out, in, len); + + for(size_t i = 0; i < num_blocks; i++) { + this->decipher((state_t*)(out + (RADIOLIB_AES128_BLOCK_SIZE * i)), this->roundKey); + } + + return(num_blocks*RADIOLIB_AES128_BLOCK_SIZE); +} + +void RadioLibAES128::generateCMAC(uint8_t* in, size_t len, uint8_t* cmac) { + uint8_t key1[RADIOLIB_AES128_BLOCK_SIZE]; + uint8_t key2[RADIOLIB_AES128_BLOCK_SIZE]; + this->generateSubkeys(key1, key2); + + size_t num_blocks = len / RADIOLIB_AES128_BLOCK_SIZE; + bool flag = true; + if(len % RADIOLIB_AES128_BLOCK_SIZE) { + num_blocks++; + flag = false; + } + + uint8_t* buff = new uint8_t[num_blocks * RADIOLIB_AES128_BLOCK_SIZE]; + memset(buff, 0, num_blocks * RADIOLIB_AES128_BLOCK_SIZE); + memcpy(buff, in, len); + if (flag) { + this->blockXor(&buff[(num_blocks - 1)*RADIOLIB_AES128_BLOCK_SIZE], &buff[(num_blocks - 1)*RADIOLIB_AES128_BLOCK_SIZE], key1); + } else { + buff[len] = 0x80; + this->blockXor(&buff[(num_blocks - 1)*RADIOLIB_AES128_BLOCK_SIZE], &buff[(num_blocks - 1)*RADIOLIB_AES128_BLOCK_SIZE], key2); + } + + uint8_t X[] = { + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00 + }; + uint8_t Y[RADIOLIB_AES128_BLOCK_SIZE]; + + for(uint8_t i = 0; i < num_blocks - 1; i++) { + this->blockXor(Y, &buff[i*RADIOLIB_AES128_BLOCK_SIZE], X); + this->encryptECB(Y, RADIOLIB_AES128_BLOCK_SIZE, X); + } + this->blockXor(Y, &buff[(num_blocks - 1)*RADIOLIB_AES128_BLOCK_SIZE], X); + this->encryptECB(Y, RADIOLIB_AES128_BLOCK_SIZE, cmac); + delete[] buff; +} + +bool RadioLibAES128::verifyCMAC(uint8_t* in, size_t len, uint8_t* cmac) { + uint8_t cmacReal[RADIOLIB_AES128_BLOCK_SIZE]; + this->generateCMAC(in, len, cmacReal); + for(size_t i = 0; i < RADIOLIB_AES128_BLOCK_SIZE; i++) { + if((cmacReal[i] != cmac[i])) { + return(false); + } + } + return(true); +} + +void RadioLibAES128::keyExpansion(uint8_t* roundKey, uint8_t* key) { + uint8_t tmp[4]; + + // the first round key is the key itself + for(uint8_t i = 0; i < RADIOLIB_AES128_N_K; i++) { + for(uint8_t j = 0; j < 4; j++) { + roundKey[(i * 4) + j] = key[(i * 4) + j]; + } + } + + // All other round keys are found from the previous round keys. + for(uint8_t i = RADIOLIB_AES128_N_K; i < RADIOLIB_AES128_N_B * (RADIOLIB_AES128_N_R + 1); ++i) { + uint8_t j = (i - 1) * 4; + for(uint8_t k = 0; k < 4; k++) { + tmp[k] = roundKey[j + k]; + } + + if(i % RADIOLIB_AES128_N_K == 0) { + this->rotWord(tmp); + this->subWord(tmp); + tmp[0] = tmp[0] ^ aesRcon[i/RADIOLIB_AES128_N_K]; + } + + j = i * 4; + uint8_t k = (i - RADIOLIB_AES128_N_K) * 4; + for(uint8_t l = 0; l < 4; l++) { + roundKey[j + l] = roundKey[k + l] ^ tmp[l]; + } + } +} + +void RadioLibAES128::cipher(state_t* state, uint8_t* roundKey) { + this->addRoundKey(0, state, roundKey); + for(uint8_t round = 1; round < RADIOLIB_AES128_N_R; round++) { + this->subBytes(state, aesSbox); + this->shiftRows(state, false); + this->mixColumns(state, false); + this->addRoundKey(round, state, roundKey); + } + + this->subBytes(state, aesSbox); + this->shiftRows(state, false); + this->addRoundKey(RADIOLIB_AES128_N_R, state, roundKey); +} + + +void RadioLibAES128::decipher(state_t* state, uint8_t* roundKey) { + this->addRoundKey(RADIOLIB_AES128_N_R, state, roundKey); + for(uint8_t round = RADIOLIB_AES128_N_R - 1; round > 0; --round) { + this->shiftRows(state, true); + this->subBytes(state, aesSboxInv); + this->addRoundKey(round, state, roundKey); + this->mixColumns(state, true); + } + + this->shiftRows(state, true); + this->subBytes(state, aesSboxInv); + this->addRoundKey(0, state, roundKey); +} + +void RadioLibAES128::subWord(uint8_t* word) { + for(size_t i = 0; i < 4; i++) { + word[i] = RADIOLIB_NONVOLATILE_READ_BYTE(&aesSbox[word[i]]); + } +} + +void RadioLibAES128::rotWord(uint8_t* word) { + uint8_t tmp[4]; + memcpy(tmp, word, 4); + for(size_t i = 0; i < 4; i++) { + word[i] = tmp[(i + 1) % 4]; + } +} + +void RadioLibAES128::addRoundKey(uint8_t round, state_t* state, uint8_t* roundKey) { + for(size_t row = 0; row < 4; row++) { + for(size_t col = 0; col < 4; col++) { + (*state)[row][col] ^= roundKey[(round * RADIOLIB_AES128_N_B * 4) + (row * RADIOLIB_AES128_N_B) + col]; + } + } +} + +void RadioLibAES128::blockXor(uint8_t* dst, uint8_t* a, uint8_t* b) { + for(uint8_t j = 0; j < RADIOLIB_AES128_BLOCK_SIZE; j++) { + dst[j] = a[j] ^ b[j]; + } +} + +void RadioLibAES128::blockLeftshift(uint8_t* dst, uint8_t* src) { + uint8_t ovf = 0x00; + for(int8_t i = RADIOLIB_AES128_BLOCK_SIZE - 1; i >= 0; i--) { + dst[i] = src[i] << 1; + dst[i] |= ovf; + ovf = (src[i] & 0x80) ? 1 : 0; + } +} + +void RadioLibAES128::generateSubkeys(uint8_t* key1, uint8_t* key2) { + uint8_t const_Zero[] = { + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00 + }; + + uint8_t const_Rb[] = { + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x87 + }; + + uint8_t L[RADIOLIB_AES128_BLOCK_SIZE]; + this->encryptECB(const_Zero, RADIOLIB_AES128_BLOCK_SIZE, L); + this->blockLeftshift(key1, L); + if(L[0] & 0x80) { + this->blockXor(key1, key1, const_Rb); + } + + this->blockLeftshift(key2, key1); + if(key1[0] & 0x80) { + this->blockXor(key2, key2, const_Rb); + } +} + +void RadioLibAES128::subBytes(state_t* state, const uint8_t* box) { + for(size_t row = 0; row < 4; row++) { + for(size_t col = 0; col < 4; col++) { + (*state)[col][row] = box[(*state)[col][row]]; + } + } +} + +void RadioLibAES128::shiftRows(state_t* state, bool inv) { + uint8_t tmp[4]; + for(size_t row = 1; row < 4; row++) { + for(size_t col = 0; col < 4; col++) { + if(!inv) { + tmp[col] = (*state)[(row + col) % 4][row]; + } else { + tmp[(row + col) % 4] = (*state)[col][row]; + } + } + for(size_t col = 0; col < 4; col++) { + (*state)[col][row] = tmp[col]; + } + } +} + +void RadioLibAES128::mixColumns(state_t* state, bool inv) { + uint8_t tmp[4]; + uint8_t matmul[][4] = { + 0x02, 0x03, 0x01, 0x01, + 0x01, 0x02, 0x03, 0x01, + 0x01, 0x01, 0x02, 0x03, + 0x03, 0x01, 0x01, 0x02 + }; + if(inv) { + uint8_t matmul_inv[][4] = { + 0x0e, 0x0b, 0x0d, 0x09, + 0x09, 0x0e, 0x0b, 0x0d, + 0x0d, 0x09, 0x0e, 0x0b, + 0x0b, 0x0d, 0x09, 0x0e + }; + memcpy(matmul, matmul_inv, sizeof(matmul_inv)); + } + + for(size_t col = 0; col < 4; col++) { + for(size_t row = 0; row < 4; row++) { + tmp[row] = (*state)[col][row]; + } + for(size_t i = 0; i < 4; i++) { + (*state)[col][i] = 0x00; + for(size_t j = 0; j < 4; j++) { + (*state)[col][i] ^= mul(matmul[i][j], tmp[j]); + } + } + } +} + +uint8_t RadioLibAES128::mul(uint8_t a, uint8_t b) { + uint8_t sb[4]; + uint8_t out = 0; + sb[0] = b; + for(size_t i = 1; i < 4; i++) { + sb[i] = sb[i - 1] << 1; + if (sb[i - 1] & 0x80) { + sb[i] ^= 0x1b; + } + } + for(size_t i = 0; i < 4; i++) { + if(a >> i & 0x01) { + out ^= sb[i]; + } + } + return(out); +} + +RadioLibAES128 RadioLibAES128Instance; diff --git a/src/utils/Cryptography.h b/src/utils/Cryptography.h new file mode 100644 index 00000000..3b7a4799 --- /dev/null +++ b/src/utils/Cryptography.h @@ -0,0 +1,173 @@ +#if !defined(_RADIOLIB_CRYPTOGRAPHY_H) +#define _RADIOLIB_CRYPTOGRAPHY_H + +#include "../TypeDef.h" +#include "../Module.h" + +// AES-128 constants +#define RADIOLIB_AES128_BLOCK_SIZE (16) +#define RADIOLIB_AES128_N_K ((RADIOLIB_AES128_BLOCK_SIZE) / sizeof(uint32_t)) +#define RADIOLIB_AES128_N_B (4) +#define RADIOLIB_AES128_N_R (10) +#define RADIOLIB_AES128_KEY_EXP_SIZE (176) + +// helper type +typedef uint8_t state_t[4][4]; + +// AES lookup tables +static const uint8_t aesSbox[] RADIOLIB_NONVOLATILE = { + 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, + 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, + 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, + 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, + 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, + 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, + 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, + 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, + 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, + 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, + 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, + 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, + 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, + 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, + 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, + 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, + 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, + 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, + 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, + 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, + 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, + 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, + 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, + 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, + 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, + 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, + 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, + 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, + 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, + 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, + 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, + 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 +}; + +static const uint8_t aesSboxInv[] RADIOLIB_NONVOLATILE = { + 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, + 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, + 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, + 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, + 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, + 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, + 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, + 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, + 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, + 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, + 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, + 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, + 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, + 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, + 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, + 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, + 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, + 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, + 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, + 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, + 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, + 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, + 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, + 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, + 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, + 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, + 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, + 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, + 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, + 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, + 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, + 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d +}; + +static const uint8_t aesRcon[] = { 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 }; + +/*! + \class RadioLibAES128 + Most of the implementation here is adapted from https://github.com/kokke/tiny-AES-c + Additional code and CMAC calculation is from https://github.com/megrxu/AES-CMAC + \brief Class to perform AES encryption, decryption and CMAC. +*/ +class RadioLibAES128 { + public: + /*! + \brief Default constructor. + */ + RadioLibAES128(); + + /*! + \brief Initialize the AES. + \param key AES key to use. + */ + void init(uint8_t* key); + + /*! + \brief Perform ECB-type AES encryption. + \param in Input plaintext data (unpadded). + \param len Length of the input data. + \param out Buffer to save the output ciphertext into. It is up to the caller + to ensure the buffer is sufficiently large to save the data! + \returns The number of bytes saved into the output buffer. + */ + size_t encryptECB(uint8_t* in, size_t len, uint8_t* out); + + /*! + \brief Perform ECB-type AES decryption. + \param in Input ciphertext data. + \param len Length of the input data. + \param out Buffer to save the output plaintext into. It is up to the caller + to ensure the buffer is sufficiently large to save the data! + \returns The number of bytes saved into the output buffer. + */ + size_t decryptECB(uint8_t* in, size_t len, uint8_t* out); + + /*! + \brief Calculate message authentication code according to RFC4493. + \param in Input data (unpadded). + \param len Length of the input data. + \param cmac Buffer to save the output MAC into. The buffer must be at least 16 bytes long! + */ + void generateCMAC(uint8_t* in, size_t len, uint8_t* cmac); + + /*! + \brief Verify the recevied CMAC. This just calculates the CMAC again and compares the results. + \param in Input data (unpadded). + \param len Length of the input data. + \param cmac CMAC to verify. + \returns True if valid, false otherwise. + */ + bool verifyCMAC(uint8_t* in, size_t len, uint8_t* cmac); + + private: + uint8_t* keyPtr; + uint8_t roundKey[RADIOLIB_AES128_KEY_EXP_SIZE]; + + void keyExpansion(uint8_t* roundKey, uint8_t* key); + void cipher(state_t* state, uint8_t* roundKey); + void decipher(state_t* state, uint8_t* roundKey); + + void subWord(uint8_t* word); + void rotWord(uint8_t* word); + + void addRoundKey(uint8_t round, state_t* state, uint8_t* roundKey); + + void blockXor(uint8_t* dst, uint8_t* a, uint8_t* b); + void blockLeftshift(uint8_t* dst, uint8_t* src); + void generateSubkeys(uint8_t* key1, uint8_t* key2); + + void subBytes(state_t* state, const uint8_t* box); + void shiftRows(state_t* state, bool inv); + void mixColumns(state_t* state, bool inv); + + uint8_t mul(uint8_t a, uint8_t b); +}; + +// the global singleton +extern RadioLibAES128 RadioLibAES128Instance; + +#endif