1 /* 2 * Copyright (c) 2023, The TrustedFirmware-M Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 * 6 */ 7 8 #ifndef CC3XX_STDLIB_H 9 #define CC3XX_STDLIB_H 10 11 #include "stdint.h" 12 #include "stddef.h" 13 14 #ifdef __cplusplus 15 extern "C" { 16 #endif 17 18 /** 19 * @brief Generate a randomized sequence of integers from 20 * 0 to len-1 inclusive, in randomized order. 21 * 22 * @param[out] permutation_buf Destination buffer to copy into. Must be len 23 * bytes in length. 24 * @param[in] len The size of the sequence to generate. 25 */ 26 void cc3xx_random_permutation_generate(uint8_t *permutation_buf, size_t len); 27 28 /** 29 * @brief Copy a series of words in a randomised order. 30 * Intended to be used as a DPA countermeasure 31 * when copying key materal. 32 * 33 * @note This function may take a variable amount of 34 * time to execute. 35 * 36 * @param[out] dst Destination buffer to copy into 37 * @param[in] src Source buffer to copy from. 38 * @param[in] word_count The amount of words to copy. 39 */ 40 void cc3xx_dpa_hardened_word_copy(volatile uint32_t *dst, 41 volatile const uint32_t *src, size_t word_count); 42 /** 43 * @brief Securely erases the buffer pointed by buf by overwriting it with random values. Assumes 44 * the size of the buffer in bytes is a multiple of 4 45 * 46 * @param[in,out] buf Pointer to the input buffer, must be 4 byte aligned 47 * @param[in] word_count Length in words of the input buffer 48 * 49 */ 50 void cc3xx_secure_erase_buffer(uint32_t *buf, size_t word_count); 51 52 #ifdef __cplusplus 53 } 54 #endif 55 56 #endif /* CC3XX_STDLIB_H */ 57
