cc2538: aes: Add support for 192- and 256-bit keys (e8a268cd) · Commits · Theo Maillart / SR04

cpu/cc2538/dev/aes.c

+23 −8

Original line number	Diff line number	Diff line
		@@ -48,18 +48,35 @@
		#include <stdint.h>
		/---------------------------------------------------------------------------/
		uint8_t
		aes_load_keys(const void *keys, uint8_t count, uint8_t start_area)
		aes_load_keys(const void *keys, uint8_t key_size, uint8_t count,
		uint8_t start_area)
		{
		uint32_t aes_key_store_size;
		uint32_t areas;
		uint32_t aligned_keys[32];
		uint64_t aligned_keys[16];
		int i;

		if(REG(AES_CTRL_ALG_SEL) != 0x00000000) {
		return CRYPTO_RESOURCE_IN_USE;
		}

		/* 192-bit keys must be padded to 256 bits */
		if(key_size == AES_KEY_STORE_SIZE_KEY_SIZE_192) {
		for(i = 0; i < count; i++) {
		rom_util_memcpy(&aligned_keys[i << 2], &((uint64_t )keys)[i 3], 24);
		aligned_keys[(i << 2) + 3] = 0;
		}
		}

		/* Change count to the number of 128-bit key areas */
		if(key_size != AES_KEY_STORE_SIZE_KEY_SIZE_128) {
		count <<= 1;
		}

		/* The keys base address needs to be 4-byte aligned */
		if(key_size != AES_KEY_STORE_SIZE_KEY_SIZE_192) {
		rom_util_memcpy(aligned_keys, keys, count << 4);
		}

		/* Workaround for AES registers not retained after PM2 */
		REG(AES_CTRL_INT_CFG) = AES_CTRL_INT_CFG_LEVEL;
		@@ -73,14 +90,12 @@ aes_load_keys(const void *keys, uint8_t count, uint8_t start_area)
		REG(AES_CTRL_INT_CLR) = AES_CTRL_INT_CLR_DMA_IN_DONE \|
		AES_CTRL_INT_CLR_RESULT_AV;

		/* Configure key store module (areas, size): 128-bit key size
		/* Configure key store module (areas, size)
		* Note that writing AES_KEY_STORE_SIZE deletes all stored keys */
		aes_key_store_size = REG(AES_KEY_STORE_SIZE);
		if((aes_key_store_size & AES_KEY_STORE_SIZE_KEY_SIZE_M) !=
		AES_KEY_STORE_SIZE_KEY_SIZE_128) {
		if((aes_key_store_size & AES_KEY_STORE_SIZE_KEY_SIZE_M) != key_size) {
		REG(AES_KEY_STORE_SIZE) = (aes_key_store_size &
		~AES_KEY_STORE_SIZE_KEY_SIZE_M) \|
		AES_KEY_STORE_SIZE_KEY_SIZE_128;
		~AES_KEY_STORE_SIZE_KEY_SIZE_M) \| key_size;
		}

		/* Free possibly already occupied key areas */

cpu/cc2538/dev/aes.h

+10 −3

Original line number	Diff line number	Diff line
		@@ -472,11 +472,18 @@

		/** \brief Writes keys into the Key RAM
		* \param keys Pointer to AES Keys
		* \param count Number of keys (1 to 8 - \p start_area)
		* \param start_area Start area in Key RAM where to store the key (0 to 7)
		* \param key_size Key size: \c AES_KEY_STORE_SIZE_KEY_SIZE_x
		* \param count Number of keys (1 to 8 - \p start_area for 128-bit keys, 1 to
		* (8 - \p start_area) / 2 for 192- and 256-bit keys)
		* \param start_area Start area in Key RAM where to store the key (0 to 7, must
		* be even for 192- and 256-bit keys)
		* \return \c CRYPTO_SUCCESS if successful, or CRYPTO/AES error code
		* \note Calling this function with a value of \p key_size different from the
		* one passed for the previous calls causes the deletion of all previously
		* stored keys.
		*/
		uint8_t aes_load_keys(const void *keys, uint8_t count, uint8_t start_area);
		uint8_t aes_load_keys(const void *keys, uint8_t key_size, uint8_t count,
		uint8_t start_area);

		/** @} */

cpu/cc2538/dev/ccm.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -99,14 +99,13 @@ ccm_auth_encrypt_start(uint8_t len_len, uint8_t key_area, const void *nonce,
		REG(AES_AES_IV_2) = iv[2];
		REG(AES_AES_IV_3) = iv[3];

		/* Program AES-CCM-128 encryption */
		/* Program AES-CCM encryption */
		REG(AES_AES_CTRL) = AES_AES_CTRL_SAVE_CONTEXT \| /* Save context */
		(((MAX(mic_len, 2) - 2) >> 1) << AES_AES_CTRL_CCM_M_S) \| /* M */
		((len_len - 1) << AES_AES_CTRL_CCM_L_S) \| /* L */
		AES_AES_CTRL_CCM \| /* CCM */
		AES_AES_CTRL_CTR_WIDTH_128 \| /* CTR width 128 */
		AES_AES_CTRL_CTR \| /* CTR */
		AES_AES_CTRL_KEY_SIZE_128 \| /* Key = 128 */
		AES_AES_CTRL_DIRECTION_ENCRYPT; /* Encryption */

		/* Write the length of the crypto block (lo) */
		@@ -278,14 +277,13 @@ ccm_auth_decrypt_start(uint8_t len_len, uint8_t key_area, const void *nonce,
		REG(AES_AES_IV_2) = iv[2];
		REG(AES_AES_IV_3) = iv[3];

		/* Program AES-CCM-128 decryption */
		/* Program AES-CCM decryption */
		REG(AES_AES_CTRL) = AES_AES_CTRL_SAVE_CONTEXT \| /* Save context */
		(((MAX(mic_len, 2) - 2) >> 1) << AES_AES_CTRL_CCM_M_S) \| /* M */
		((len_len - 1) << AES_AES_CTRL_CCM_L_S) \| /* L */
		AES_AES_CTRL_CCM \| /* CCM */
		AES_AES_CTRL_CTR_WIDTH_128 \| /* CTR width 128 */
		AES_AES_CTRL_CTR \| /* CTR */
		AES_AES_CTRL_KEY_SIZE_128; /* Key = 128 */
		AES_AES_CTRL_CTR; /* CTR */

		/* Write the length of the crypto block (lo) */
		REG(AES_AES_C_LENGTH_0) = pdata_len;

examples/cc2538dk/crypto/ccm-test.c

+413 −19

File changed.

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platform/cc2538dk/README.md

+1 −1

Original line number	Diff line number	Diff line
		@@ -29,7 +29,7 @@ In terms of hardware support, the following drivers have been implemented:
		* Low Power Modes
		* General-Purpose Timers. NB: GPT0 is in use by the platform code, the remaining GPTs are available for application development.
		* ADC
		* Cryptoprocessor (AES-CCM-128, SHA-256)
		* Cryptoprocessor (AES-CCM-256, SHA-256)
		* SmartRF06 EB and BB peripherals
		* LEDs
		* Buttons

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