ECDHCC26X1.h

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/*
 * Copyright (c) 2020-2021, Texas Instruments Incorporated
 * All rights reserved.
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 *    notice, this list of conditions and the following disclaimer.
 *
 * *  Redistributions in binary form must reproduce the above copyright
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 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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#ifndef ti_drivers_ecdh_ECDHCC26X1__include
#define ti_drivers_ecdh_ECDHCC26X1__include

#include <stdint.h>
#include <stdbool.h>

#include <ti/drivers/ECDH.h>

#include <ti/devices/DeviceFamily.h>
#include DeviceFamily_constructPath(driverlib/rom_ecc.h)

#ifdef __cplusplus
extern "C" {
#endif

typedef struct {
    uint8_t    dummy;
} ECDHCC26X1_HWAttrs;

/*
 * Performance of the ECC SW library is scaled via the window size parameter
 * which defines the number of bits of the scalar that will be processed together
 * during the execution of the scalar multiplication. A larger window size
 * will have higher performance at the cost of increased memory consumption.
 * A window size of 3 was selected for the best trade-off of performance and
 * memory consumption.
 *
 * ---------------------------------------------------
 * |             |    NIST P256    |     X25519      |
 * | Window Size |  WorkZone Size  |  WorkZone Size  |
 * |             |     (words)     |     (words)     |
 * |-------------|-----------------|-----------------|
 * |   2 or 3    |       171       |       198       |
 * |      4      |       225       |       225       |
 * |      5      |       333       |       333       |
 * ---------------------------------------------------
 */
#define ECDH26X1_ECC_WINDOW_SIZE  3

/*
 * ECC Workzone size is based on worst case empirical measurement of ECDH
 * operations on supported curves with the selected window size.
 *    NIST P256  (win_size=3): 171 words
 *    Curve25519 (win_size=3): 198 words
 */
#define ECDH26X1_ECC_WORKZONE_WORDS  198

typedef struct {
    bool                            isOpen;
    ECDH_CallbackFxn                callbackFxn;
    ECDH_ReturnBehavior             returnBehavior; /* Note: Callback return behavior is not supported */
    ECC_State                       eccState;
    uint32_t                        eccWorkZone[ECDH26X1_ECC_WORKZONE_WORDS];
} ECDHCC26X1_Object;

#ifdef __cplusplus
}
#endif

#endif /* ti_drivers_ecdh_ECDHCC26X1__include */