92 lines
2.7 KiB
C
92 lines
2.7 KiB
C
#include <string.h>
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#include <stdlib.h>
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#include "mbedtls/entropy.h"
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#include "mbedtls/ctr_drbg.h"
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#include "mbedtls/aes.h"
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/**
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* functions for aes encryption
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*/
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/**
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* Generate a new AES key
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* @param key where to store the 32 byte key
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* @returns true(1) on success
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*/
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int libp2p_crypto_aes_key_generate(char* key) {
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mbedtls_entropy_context entropy;
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mbedtls_ctr_drbg_context ctr_drbg;
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mbedtls_entropy_init(&entropy);
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char* pers = "aes generate key";
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mbedtls_ctr_drbg_init(&ctr_drbg);
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if (mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
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(const unsigned char *) pers,
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strlen( pers )) != 0)
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return 0;
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if (mbedtls_ctr_drbg_random(&ctr_drbg, key, 32) != 0)
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return 0;
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return 1;
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}
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/**
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* Encrypt a block of text
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* @param key the aes key (32 bytes)
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* @param iv the random part of encryption (16 bytes)
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* @param input the text to encrypt
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* @param input_size the length of the array
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* @param output where the output will be placed
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* @param output_size the length of the memory allocated for output
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* @returns true(1) on success, otherwise false(0)
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*/
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int libp2p_crypto_aes_encrypt(char* key, char* iv, char* input, size_t input_size, unsigned char** output, size_t* output_size) {
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int new_size = 0;
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mbedtls_aes_context ctx;
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mbedtls_aes_init(&ctx);
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mbedtls_aes_setkey_enc(&ctx, key, 256);
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// turn input into a multiple of 16
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new_size = input_size;
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if (new_size % 16 != 0) {
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new_size += new_size % 16;
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}
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char* padded_input = malloc(new_size);
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memcpy(padded_input, input, input_size);
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if (new_size != input_size)
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memset(&padded_input[input_size], 0, new_size - input_size);
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// make room for the output
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*output = malloc(new_size);
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*output_size = new_size;
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int retVal = mbedtls_aes_crypt_cbc(&ctx, MBEDTLS_AES_ENCRYPT, new_size, iv, padded_input, *output);
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free(padded_input);
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if (retVal != 0)
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free(output);
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return retVal == 0;
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}
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/**
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* Decrypt a block of text
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* @param key the aes key (32 bytes)
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* @param iv the random part of encryption (16 bytes)
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* @param input the text to encrypt
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* @param input_size the length of the array
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* @param output where the output will be placed
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* @param output_size the length of the memory allocated for output
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* @returns true(1) on success, otherwise false(0)
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*/
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int libp2p_crypto_aes_decrypt(char* key, char* iv, char* input, size_t input_size, unsigned char** output, size_t* output_size) {
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mbedtls_aes_context ctx;
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mbedtls_aes_init(&ctx);
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mbedtls_aes_setkey_dec(&ctx, key, 256);
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// make room for the output
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*output = malloc(input_size);
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*output_size = input_size;
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if (mbedtls_aes_crypt_cbc(&ctx, MBEDTLS_AES_DECRYPT, input_size, iv, input, *output) != 0)
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return 0;
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return 1;
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}
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