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feat(bt): support hardware ecc acceleration for bt tinycrypt

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This commit is contained in:
Shen Weilong
2025-03-04 18:12:49 +08:00
parent 8d57c19015
commit 5c8b66f314
4 changed files with 154 additions and 30 deletions
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4
components/bt/CMakeLists.txt
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@@ -545,6 +545,7 @@ if(CONFIG_BT_ENABLED)
if(NOT (CONFIG_BT_LE_CRYPTO_STACK_MBEDTLS OR CONFIG_BT_NIMBLE_CRYPTO_STACK_MBEDTLS))
list(APPEND include_dirs
common/tinycrypt/include
common/tinycrypt/port
)
list(APPEND srcs "common/tinycrypt/src/utils.c"
"common/tinycrypt/src/sha256.c"
@@ -560,7 +561,8 @@ if(CONFIG_BT_ENABLED)
"common/tinycrypt/src/hmac_prng.c"
"common/tinycrypt/src/ecc_platform_specific.c"
"common/tinycrypt/src/hmac.c"
"common/tinycrypt/src/cbc_mode.c")
"common/tinycrypt/src/cbc_mode.c"
"common/tinycrypt/port/esp_tinycrypt_port.c")
endif()
if(CONFIG_BT_NIMBLE_ENABLED)

78
components/bt/common/tinycrypt/port/esp_tinycrypt_port.c Normal file
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@@ -0,0 +1,78 @@
/*
* SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include "esp_tinycrypt_port.h"
#if SOC_ECC_SUPPORTED
#include "esp_crypto_lock.h"
#include "esp_private/periph_ctrl.h"
#include "hal/ecc_hal.h"
#include "hal/ecc_ll.h"
static void esp_tinycrypt_acquire_ecc_hardware(void)
{
esp_crypto_ecc_lock_acquire();
periph_module_enable(PERIPH_ECC_MODULE);
ecc_ll_power_up();
}
static void esp_tinycrypt_release_ecc_hardware(void)
{
periph_module_disable(PERIPH_ECC_MODULE);
ecc_ll_power_down();
esp_crypto_ecc_lock_release();
}
int esp_tinycrypt_verify_ecc_point(const uint8_t *pk_x, const uint8_t *pk_y, uint8_t length)
{
int result;
esp_tinycrypt_acquire_ecc_hardware();
ecc_hal_write_verify_param(pk_x, pk_y, length);
ecc_hal_set_mode(ECC_MODE_VERIFY);
ecc_hal_start_calc();
while (!ecc_hal_is_calc_finished());
result = ecc_hal_read_verify_result();
esp_tinycrypt_release_ecc_hardware();
if (result == 1) {
return 0;
} else {
return -1;
}
}
int esp_tinycrypt_calc_ecc_mult(const uint8_t *p_x, const uint8_t *p_y, const uint8_t *scalar,
uint8_t *r_x, uint8_t *r_y, uint8_t num_bytes, bool verify_first)
{
int ret = -1;
ecc_mode_t work_mode = verify_first ? ECC_MODE_VERIFY_THEN_POINT_MUL : ECC_MODE_POINT_MUL;
esp_tinycrypt_acquire_ecc_hardware();
ecc_hal_write_mul_param(scalar, p_x, p_y, num_bytes);
ecc_hal_set_mode(work_mode);
/*
* Enable constant-time point multiplication operations for the ECC hardware accelerator,
* if supported for the given target. This protects the ECC multiplication operation from
* timing attacks. This increases the time taken (by almost 50%) for some point
* multiplication operations performed by the ECC hardware accelerator.
*/
ecc_hal_enable_constant_time_point_mul(true);
ecc_hal_start_calc();
while (!ecc_hal_is_calc_finished());
ret = ecc_hal_read_mul_result(r_x, r_y, num_bytes);
esp_tinycrypt_release_ecc_hardware();
return ret;
}
#endif /* SOC_ECC_SUPPORTED */

15
components/bt/common/tinycrypt/port/esp_tinycrypt_port.h Normal file
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@@ -0,0 +1,15 @@
/*
* SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <stdint.h>
#include <stdbool.h>
#include "soc/soc_caps.h"
#if SOC_ECC_SUPPORTED
int esp_tinycrypt_verify_ecc_point(const uint8_t *pk_x, const uint8_t *pk_y, uint8_t length);
int esp_tinycrypt_calc_ecc_mult(const uint8_t *p_x, const uint8_t *p_y, const uint8_t *scalar,
uint8_t *r_x, uint8_t *r_y, uint8_t num_bytes, bool verify_first);
#endif /* SOC_ECC_SUPPORTED */

87
components/bt/common/tinycrypt/src/ecc.c
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@@ -59,6 +59,9 @@
#include <tinycrypt/ecc.h>
#include <tinycrypt/ecc_platform_specific.h>
#include <string.h>
#include <stdio.h>
#include "esp_tinycrypt_port.h"
/* IMPORTANT: Make sure a cryptographically-secure PRNG is set and the platform
* has access to enough entropy in order to feed the PRNG regularly. */
@@ -639,6 +642,7 @@ void apply_z(uECC_word_t * X1, uECC_word_t * Y1, const uECC_word_t * const Z,
uECC_vli_modMult_fast(Y1, Y1, t1, curve); /* y1 * z^3 */
}
#if !SOC_ECC_SUPPORTED
/* P = (x1, y1) => 2P, (x2, y2) => P' */
static void XYcZ_initial_double(uECC_word_t * X1, uECC_word_t * Y1,
uECC_word_t * X2, uECC_word_t * Y2,
@@ -662,31 +666,6 @@ static void XYcZ_initial_double(uECC_word_t * X1, uECC_word_t * Y1,
apply_z(X2, Y2, z, curve);
}
void XYcZ_add(uECC_word_t * X1, uECC_word_t * Y1,
uECC_word_t * X2, uECC_word_t * Y2,
uECC_Curve curve)
{
/* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
uECC_word_t t5[NUM_ECC_WORDS];
wordcount_t num_words = curve->num_words;
uECC_vli_modSub(t5, X2, X1, curve->p, num_words); /* t5 = x2 - x1 */
uECC_vli_modSquare_fast(t5, t5, curve); /* t5 = (x2 - x1)^2 = A */
uECC_vli_modMult_fast(X1, X1, t5, curve); /* t1 = x1*A = B */
uECC_vli_modMult_fast(X2, X2, t5, curve); /* t3 = x2*A = C */
uECC_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = y2 - y1 */
uECC_vli_modSquare_fast(t5, Y2, curve); /* t5 = (y2 - y1)^2 = D */
uECC_vli_modSub(t5, t5, X1, curve->p, num_words); /* t5 = D - B */
uECC_vli_modSub(t5, t5, X2, curve->p, num_words); /* t5 = D - B - C = x3 */
uECC_vli_modSub(X2, X2, X1, curve->p, num_words); /* t3 = C - B */
uECC_vli_modMult_fast(Y1, Y1, X2, curve); /* t2 = y1*(C - B) */
uECC_vli_modSub(X2, X1, t5, curve->p, num_words); /* t3 = B - x3 */
uECC_vli_modMult_fast(Y2, Y2, X2, curve); /* t4 = (y2 - y1)*(B - x3) */
uECC_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = y3 */
uECC_vli_set(X2, t5, num_words);
}
/* Input P = (x1, y1, Z), Q = (x2, y2, Z)
Output P + Q = (x3, y3, Z3), P - Q = (x3', y3', Z3)
@@ -729,12 +708,49 @@ static void XYcZ_addC(uECC_word_t * X1, uECC_word_t * Y1,
uECC_vli_set(X1, t7, num_words);
}
#endif /* !SOC_ECC_SUPPORTED */
void XYcZ_add(uECC_word_t * X1, uECC_word_t * Y1,
uECC_word_t * X2, uECC_word_t * Y2,
uECC_Curve curve)
{
/* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
uECC_word_t t5[NUM_ECC_WORDS];
wordcount_t num_words = curve->num_words;
uECC_vli_modSub(t5, X2, X1, curve->p, num_words); /* t5 = x2 - x1 */
uECC_vli_modSquare_fast(t5, t5, curve); /* t5 = (x2 - x1)^2 = A */
uECC_vli_modMult_fast(X1, X1, t5, curve); /* t1 = x1*A = B */
uECC_vli_modMult_fast(X2, X2, t5, curve); /* t3 = x2*A = C */
uECC_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = y2 - y1 */
uECC_vli_modSquare_fast(t5, Y2, curve); /* t5 = (y2 - y1)^2 = D */
uECC_vli_modSub(t5, t5, X1, curve->p, num_words); /* t5 = D - B */
uECC_vli_modSub(t5, t5, X2, curve->p, num_words); /* t5 = D - B - C = x3 */
uECC_vli_modSub(X2, X2, X1, curve->p, num_words); /* t3 = C - B */
uECC_vli_modMult_fast(Y1, Y1, X2, curve); /* t2 = y1*(C - B) */
uECC_vli_modSub(X2, X1, t5, curve->p, num_words); /* t3 = B - x3 */
uECC_vli_modMult_fast(Y2, Y2, X2, curve); /* t4 = (y2 - y1)*(B - x3) */
uECC_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = y3 */
uECC_vli_set(X2, t5, num_words);
}
void EccPoint_mult(uECC_word_t * result, const uECC_word_t * point,
const uECC_word_t * scalar,
const uECC_word_t * initial_Z,
bitcount_t num_bits, uECC_Curve curve)
{
#if SOC_ECC_SUPPORTED
wordcount_t num_words = curve->num_words;
/* Only p256r1 is supported currently. */
assert (curve == uECC_secp256r1());
esp_tinycrypt_calc_ecc_mult((const uint8_t *)&point[0], (const uint8_t *)&point[num_words],
(uint8_t *)scalar, (uint8_t *)&result[0], (uint8_t *)&result[num_words],
num_words * uECC_WORD_SIZE, false);
#else
/* R0 and R1 */
uECC_word_t Rx[2][NUM_ECC_WORDS];
uECC_word_t Ry[2][NUM_ECC_WORDS];
@@ -773,6 +789,7 @@ void EccPoint_mult(uECC_word_t * result, const uECC_word_t * point,
uECC_vli_set(result, Rx[0], num_words);
uECC_vli_set(result + num_words, Ry[0], num_words);
#endif /* SOC_ECC_SUPPORTED */
}
uECC_word_t regularize_k(const uECC_word_t * const k, uECC_word_t *k0,
@@ -866,8 +883,6 @@ int uECC_generate_random_int(uECC_word_t *random, const uECC_word_t *top,
int uECC_valid_point(const uECC_word_t *point, uECC_Curve curve)
{
uECC_word_t tmp1[NUM_ECC_WORDS];
uECC_word_t tmp2[NUM_ECC_WORDS];
wordcount_t num_words = curve->num_words;
/* The point at infinity is invalid. */
@@ -881,19 +896,34 @@ int uECC_valid_point(const uECC_word_t *point, uECC_Curve curve)
return -2;
}
#if SOC_ECC_SUPPORTED
/* Only p256r1 is supported currently. */
if (curve != uECC_secp256r1()) {
return -5;
}
if (esp_tinycrypt_verify_ecc_point((const uint8_t *)&point[0],
(const uint8_t *)&point[num_words],
num_words * uECC_WORD_SIZE)) {
return -3;
}
#else
uECC_word_t tmp1[NUM_ECC_WORDS];
uECC_word_t tmp2[NUM_ECC_WORDS];
uECC_vli_modSquare_fast(tmp1, point + num_words, curve);
curve->x_side(tmp2, point, curve); /* tmp2 = x^3 + ax + b */
/* Make sure that y^2 == x^3 + ax + b */
if (uECC_vli_equal(tmp1, tmp2, num_words) != 0)
return -3;
#endif /* SOC_ECC_SUPPORTED */
return 0;
}
int uECC_valid_public_key(const uint8_t *public_key, uECC_Curve curve)
{
uECC_word_t _public[NUM_ECC_WORDS * 2];
uECC_vli_bytesToNative(_public, public_key, curve->num_bytes);
@@ -912,7 +942,6 @@ int uECC_valid_public_key(const uint8_t *public_key, uECC_Curve curve)
int uECC_compute_public_key(const uint8_t *private_key, uint8_t *public_key,
uECC_Curve curve)
{
uECC_word_t _private[NUM_ECC_WORDS];
uECC_word_t _public[NUM_ECC_WORDS * 2];