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https://github.com/espressif/esp-idf.git
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32a6550e87
ESP32C2 has a ECC hardware accelerator capable of performing point multiplication and point verification with a significant performance boost
130 lines
3.9 KiB
C
130 lines
3.9 KiB
C
/*
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* SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <string.h>
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#include "soc/hwcrypto_periph.h"
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#include "ecc_impl.h"
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/* TBD: Remove this and use proper getter/setter methods to access
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* private members of EC data structures once they are available
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* in mbedTLS stack */
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#define MBEDTLS_ALLOW_PRIVATE_ACCESS
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#include "mbedtls/ecp.h"
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#include "mbedtls/platform_util.h"
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#define ECP_VALIDATE_RET( cond ) \
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MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_ECP_BAD_INPUT_DATA )
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#define ECP_VALIDATE( cond ) \
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MBEDTLS_INTERNAL_VALIDATE( cond )
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#if defined(MBEDTLS_ECP_MUL_ALT) || defined(MBEDTLS_ECP_MUL_ALT_SOFT_FALLBACK)
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#define MAX_SIZE 32 // 256 bits
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static int esp_mbedtls_ecp_point_multiply(const mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
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const mbedtls_mpi *m, const mbedtls_ecp_point *P)
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{
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int ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
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uint8_t x_tmp[MAX_SIZE];
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uint8_t y_tmp[MAX_SIZE];
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ecc_point_t p_pt = {0};
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ecc_point_t r_pt = {0};
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p_pt.len = grp->pbits / 8;
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memcpy(&p_pt.x, P->X.p, mbedtls_mpi_size(&P->X));
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memcpy(&p_pt.y, P->Y.p, mbedtls_mpi_size(&P->Y));
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ret = esp_ecc_point_multiply(&p_pt, (uint8_t *)m->p, &r_pt, false);
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for (int i = 0; i < MAX_SIZE; i++) {
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x_tmp[MAX_SIZE - i - 1] = r_pt.x[i];
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y_tmp[MAX_SIZE - i - 1] = r_pt.y[i];
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}
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mbedtls_mpi_read_binary(&R->X, x_tmp, MAX_SIZE);
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mbedtls_mpi_read_binary(&R->Y, y_tmp, MAX_SIZE);
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mbedtls_mpi_lset(&R->Z, 1);
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return ret;
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}
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/*
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* Restartable multiplication R = m * P
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*/
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int mbedtls_ecp_mul_restartable( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
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const mbedtls_mpi *m, const mbedtls_ecp_point *P,
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int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
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mbedtls_ecp_restart_ctx *rs_ctx )
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{
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int ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
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if (grp->id != MBEDTLS_ECP_DP_SECP192R1 && grp->id != MBEDTLS_ECP_DP_SECP256R1) {
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#if defined(MBEDTLS_ECP_MUL_ALT_SOFT_FALLBACK)
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return mbedtls_ecp_mul_restartable_soft(grp, R, m, P, f_rng, p_rng, rs_ctx);
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#else
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return ret;
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#endif
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}
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ECP_VALIDATE_RET( grp != NULL );
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ECP_VALIDATE_RET( R != NULL );
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ECP_VALIDATE_RET( m != NULL );
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ECP_VALIDATE_RET( P != NULL );
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/* Common sanity checks */
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MBEDTLS_MPI_CHK( mbedtls_ecp_check_privkey( grp, m ) );
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MBEDTLS_MPI_CHK( mbedtls_ecp_check_pubkey( grp, P ) );
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ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
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/* MBEDTLS_MPI_CHK macro assigns the return value of the function to
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* `ret` variable
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*/
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MBEDTLS_MPI_CHK( esp_mbedtls_ecp_point_multiply(grp, R, m, P) );
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cleanup:
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return( ret );
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}
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#endif /* defined(MBEDTLS_ECP_MUL_ALT) || defined(MBEDTLS_ECP_MUL_ALT_SOFT_FALLBACK) */
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#if defined(MBEDTLS_ECP_VERIFY_ALT) || defined(MBEDTLS_ECP_VERIFY_ALT_SOFT_FALLBACK)
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int mbedtls_ecp_check_pubkey( const mbedtls_ecp_group *grp,
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const mbedtls_ecp_point *pt )
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{
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int res;
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ecc_point_t point;
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if (grp->id != MBEDTLS_ECP_DP_SECP192R1 && grp->id != MBEDTLS_ECP_DP_SECP256R1) {
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#if defined(MBEDTLS_ECP_VERIFY_ALT_SOFT_FALLBACK)
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return mbedtls_ecp_check_pubkey_soft(grp, pt);
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#else
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return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
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#endif
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}
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ECP_VALIDATE_RET( grp != NULL );
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ECP_VALIDATE_RET( pt != NULL );
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/* Must use affine coordinates */
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if( mbedtls_mpi_cmp_int( &pt->Z, 1 ) != 0 )
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return( MBEDTLS_ERR_ECP_INVALID_KEY );
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mbedtls_platform_zeroize((void *)&point, sizeof(ecc_point_t));
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memcpy(&point.x, pt->X.p, mbedtls_mpi_size(&pt->X));
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memcpy(&point.y, pt->Y.p, mbedtls_mpi_size(&pt->Y));
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point.len = grp->pbits / 8;
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res = esp_ecc_point_verify(&point);
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if (res == 1) {
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return 0;
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} else {
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return MBEDTLS_ERR_ECP_INVALID_KEY;
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}
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}
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#endif /* defined(MBEDTLS_ECP_VERIFY_ALT) || defined(MBEDTLS_ECP_VERIFY_ALT_SOFT_FALLBACK) */
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