Detailed Description

AESCCM driver implementation for the Low Power F3 family.

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CCM Specification

This implementation follows NIST 800-38c - https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38c.pdf All symbols used in the implementation for identifiers and in the comments including but not limited to B0, B1 and S0 are all adopted from this NIST 800-38c.

Hardware Accelerator

The Low Power F3 family of devices has dedicated hardware accelerators. CC23XX devices have one dedicated accelerator whereas CC27XX devices have two (Primary and Secondary). Combined they can perform AES encryption operations with 128-bit, 192-bit and 256-bit keys. Only one operation can be carried out on the accelerator at a time. Mutual exclusion is implemented at the driver level and coordinated between all drivers relying on the accelerator. It is transparent to the application and only noted to ensure sensible access timeouts are set.

Implementation Limitations

Only plaintext CryptoKeys are supported by this implementation.
Maximum AAD length is limited to 65279-bytes.

The following limitations apply to the AESCCMLPF3 Driver for CC27xx device family only:

The CryptoKey input must have the correct encoding, CryptoKey.h.
The application can only use one handle per driver. Concurrent dynamic instances will be supported in the future.
CCM driver only supports polling return behaviour. Blocking and callback return behaviours will be supported in the future.

Runtime Parameter Validation

The driver implementation does not perform runtime checks for most input parameters. Only values that are likely to have a stochastic element to them are checked (such as whether a driver is already open). Higher input parameter validation coverage is achieved by turning on assertions when compiling the driver.

#include <stdbool.h>
#include <stdint.h>
#include <ti/drivers/AESCCM.h>
#include <ti/drivers/cryptoutils/aes/AESCommonLPF3.h>
#include <ti/devices/DeviceFamily.h>
#include <DeviceFamily_constructPath(driverlib/aes.h)>

Include dependency graph for AESCCMLPF3.h:

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Go to the source code of this file.

Data Structures
struct	AESCCMLPF3_Object
	AESCCMLPF3 Object. More...

Macros
#define	AESCCMLPF3_AAD_BUFFER_SIZE 2U

Typedefs
typedef AESCommonLPF3_HWAttrs	AESCCMLPF3_HWAttrs
	AESCCMLPF3 Hardware Attributes. More...

Functions
int_fast16_t	AESCCMLPF3HSM_setMac (AESCCM_Handle handle, const uint8_t *mac, size_t macLength)
	Function to set the mac for an AES CCM segmented operation. This API needs to be called only when the subsequent AESCCM_addData() operation is processing all of the remaining data in a single call. More...

Macro Definition Documentation

§ AESCCMLPF3_AAD_BUFFER_SIZE

#define AESCCMLPF3_AAD_BUFFER_SIZE 2U

Typedef Documentation

§ AESCCMLPF3_HWAttrs

typedef AESCommonLPF3_HWAttrs AESCCMLPF3_HWAttrs

AESCCMLPF3 Hardware Attributes.

AESCCMLPF3 hardware attributes should be included in the board file and pointed to by the AESCCM_config struct.

Function Documentation

§ AESCCMLPF3HSM_setMac()

int_fast16_t AESCCMLPF3HSM_setMac	(	AESCCM_Handle	handle,
		const uint8_t *	mac,
		size_t	macLength
	)

Function to set the mac for an AES CCM segmented operation. This API needs to be called only when the subsequent AESCCM_addData() operation is processing all of the remaining data in a single call.

Note: This API is only concerned with segmented decryption operations.

Precondition: AESCCM_setupDecrypt(), AESCCM_setLengths(), or AESCCM_addAAD()

Parameters

[in]	handle	A CCM handle returned from AESCCM_open() or AESCCM_construct()
[in]	mac	Pointer to the buffer containing the mac
[in]	macLength	The length of the mac in bytes

Return values

AESCCM_STATUS_SUCCESS	The operation succeeded.
AESCCM_STATUS_ERROR	The operation failed.
AESCCM_STATUS_FEATURE_NOT_SUPPORTED	The operation is not supported in this device.

Postcondition: AESCCM_addData()