英文:
Trying to encrypt communication with ESP32 (PlatformIO). esp_aes_crypt_ecb fails on the last block
问题
我正在尝试从ESP32加密数据到一个互联网网页。
明文长度为31个字符，需要3个16字符的块。
前两个块可以正常加密，但最后一个失败了。
最后一个块以C/C++字符串标准的0终止。
请查看我的参考代码：
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_system.h"
#include "esp_spi_flash.h"
#include "mbedtls/aes.h"
#include "esp_log.h"
#include "aes/esp_aes.h"
#include "mbedtls/base64.h"
#define ESP_AES_ENCRYPT 1
esp_aes_context aes;
unsigned char key[33] = {'d', 'v', 'i', 'z', 'd', 'u', 'm', 'c', 's', 'm', 'v', 'l', 'v', 'f', 'd', 'v', 'b', 'j', 's', 'v', 'd', 'u', 'i', 'a', 's', 'r', 'u', 'i', 'a', 'e', 'u', 'y', '\0'};
unsigned char encrypted[255] = {0};
void crypto_aes_ecb(char *input){
static const char *TAG = "CryptTest";
bool doEncrypt = true;
uint16_t blockIndex = 0;
uint16_t inputIndex = 0;
uint16_t outputIndex = 0;
// unsigned char input[64] = {'T', 'e', 's', 't', 'i', 'n', 'g', ' ', 'e', 'n', 'c', 'r', 'y', 'p', 't', 'i', 'o', 'n', '.', '.', '.', ' ', 'T', 'e', 's', 't', 'i', 'n', 'g', ' ', 'e', 'n', 'c', 'r', 'y', 'p', 't', 'i', 'o', 'n', '.', '.', '.', '\0'};
unsigned char inputBlock[16] = {0};
unsigned char output[17] = {0};
esp_aes_init(&aes);
esp_aes_setkey(&aes, (const unsigned char*) key, 256);
inputIndex = 0;
while(doEncrypt){
for (blockIndex = 0; blockIndex < 16; blockIndex++){
inputBlock[blockIndex] = input[blockIndex + (inputIndex * 16)];
if(input[blockIndex + (inputIndex * 16)] == '\0'){
for (; blockIndex < 16; blockIndex++){inputBlock[blockIndex] = 0;}
doEncrypt = false;
break;
}
}
inputIndex++;
inputBlock[16] = '\0';
ESP_LOGI(TAG, "inputBlock = '%s'", inputBlock);
esp_aes_crypt_ecb(&aes, ESP_AES_ENCRYPT, (const unsigned char *)inputBlock, output);
for (blockIndex = 0; blockIndex < 16; blockIndex++){
encrypted[blockIndex + (outputIndex * 16)] = output[blockIndex];
}
outputIndex++;
}
ESP_LOGW(TAG, "-----------------------------------------------------------------------------------");
ESP_LOGW(TAG, "Key : '%s'", key);
ESP_LOGW(TAG, "Input : '%s'", input);
// ESP_LOGW(TAG, "Output : '%s'", encrypted);
ESP_LOG_BUFFER_HEXDUMP(TAG, encrypted, 128, ESP_LOG_WARN);
esp_aes_free(&aes);
}
void app_main(){
crypto_aes_ecb("Testing encryption... Testing encryption...");
}
通过使用在线的加密/解密测试工具测试HexDump，它报告“给定的最终块未正确填充。如果在解密过程中使用了错误的密钥，可能会出现此类问题。”
测试明文时，我可以看到最后一个块与我的ESP32不同。
有没有办法解决这个问题？
测试网站：https://www.devglan.com/online-tools/aes-encryption-decryption
从ESP32的Dump：
ea 99 ca 39 2b 62 58 ce 71 5a 75 62 fe ac b7 f0 29 16 0c 1e 20 f5 ba 6f b0 7e c7 ee 0b eb 3a e3 89 51 f4 84 97 61 4b e8 66 22 78 72 60 0f 3e 2d
来自网页的结果：
EA 99 CA 39 2B 62 58 CE 71 5A 75 62 FE AC B7 F0 29 16 0C 1E 20 F5 BA 6F B0 7E C7 EE 0B EB 3A E3 3F 3E 65 3F 78 BA AD 13 AE 74 3E 99 44 1F E1 E5
我已经尝试过Google加密方法，但没有成功。大多数示例都会导致编译错误。
我也尝试了ChatGPT。同样会导致编译错误。
它们警告我使用ECB加密是不安全的。这个警告不适用于我。我的ESP32只会在更新秘密密钥之前发送10-15个块。
英文:
I am trying to encrypt data from ESP32 to an Internet webpage.
The plain text is 31 characters long and will need 3 blocks of 16 characters.
The 2 first blocks encrypts fine, but the last one fails.
The last block is terminated by a 0 in spec for C/C++ string standard.
Please have a look at my code for ref:
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_system.h"
#include "esp_spi_flash.h"
#include "mbedtls/aes.h"
#include "esp_log.h"
#include "aes/esp_aes.h"
#include "mbedtls/base64.h"
#define ESP_AES_ENCRYPT 1
esp_aes_context aes;
unsigned char key[33] = {'d', 'v', 'i', 'z', 'd', 'u', 'm', 'c', 's', 'm', 'v', 'l', 'v', 'f', 'd', 'v', 'b', 'j', 's', 'v', 'd', 'u', 'i', 'a', 's', 'r', 'u', 'i', 'a', 'e', 'u', 'y', '\0'};
unsigned char encrypted[255] = {0};
void crypto_aes_ecb(char *input){
static const char *TAG = "CryptTest";
bool doEncrypt = true;
uint16_t blockIndex = 0;
uint16_t inputIndex = 0;
uint16_t outputIndex = 0;
// unsigned char input[64] = {'T', 'e', 's', 't', 'i', 'n', 'g', ' ', 'e', 'n', 'c', 'r', 'y', 'p', 't', 'i', 'o', 'n', '.', '.', '.', ' ', 'T', 'e', 's', 't', 'i', 'n', 'g', ' ', 'e', 'n', 'c', 'r', 'y', 'p', 't', 'i', 'o', 'n', '.', '.', '.', '\0'};
unsigned char inputBlock[16] = {0};
unsigned char output[17] = {0};
esp_aes_init(&aes);
esp_aes_setkey(&aes, (const unsigned char*) key, 256);
inputIndex = 0;
while(doEncrypt){
for (blockIndex = 0; blockIndex < 16; blockIndex++){
inputBlock[blockIndex] = input[blockIndex + (inputIndex * 16)];
if(input[blockIndex + (inputIndex * 16)] == '\0'){
for (; blockIndex < 16; blockIndex++){inputBlock[blockIndex] = 0;}
doEncrypt = false;
break;
}
}
inputIndex++;
inputBlock[16] = '\0';
ESP_LOGI(TAG, "inputBlock = '%s'", inputBlock);
esp_aes_crypt_ecb(&aes, ESP_AES_ENCRYPT, (const unsigned char *)inputBlock, output);
for (blockIndex = 0; blockIndex < 16; blockIndex++){
encrypted[blockIndex + (outputIndex * 16)] = output[blockIndex];
}
outputIndex++;
}
ESP_LOGW(TAG, "-----------------------------------------------------------------------------------");
ESP_LOGW(TAG, "Key : '%s'", key);
ESP_LOGW(TAG, "Input : '%s'", input);
// ESP_LOGW(TAG, "Output : '%s'", encrypted);
ESP_LOG_BUFFER_HEXDUMP(TAG, encrypted, 128, ESP_LOG_WARN);
esp_aes_free(&aes);
}
void app_main(){
crypto_aes_ecb("Testing encryption... Testing encryption...");
}
Testing the HexDump with an online encrypt / decrypt tester, it reports "Given final block not properly padded. Such issues can arise if a bad key is used during decryption."
Testing the plain text, I can see that the last block is different than my ESP32.
Any idea how to solve this?
Test web site : https://www.devglan.com/online-tools/aes-encryption-decryption
Dump from ESP32 :
ea 99 ca 39 2b 62 58 ce 71 5a 75 62 fe ac b7 f0 29 16 0c 1e 20 f5 ba 6f b0 7e c7 ee 0b eb 3a e3 89 51 f4 84 97 61 4b e8 66 22 78 72 60 0f 3e 2d
Result from web page :
EA 99 CA 39 2B 62 58 CE 71 5A 75 62 FE AC B7 F0 29 16 0C 1E 20 F5 BA 6F B0 7E C7 EE 0B EB 3A E3 3F 3E 65 3F 78 BA AD 13 AE 74 3E 99 44 1F E1 E5
I have tried Googling the encryption method, but no success. Most examples results in compile error.
I have tried ChatGPT. Also results in compile errors.
They warn me of "unsafe" encryption using ECB. The warning does not apply to me. My ESP32 will only send 10-15 blocks before the Secret Key is updated.
答案1
得分: 0
// --- ESP32 侧 ---
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_system.h"
#include "esp_spi_flash.h"
#include "mbedtls/aes.h"
#include "esp_log.h"
#include "aes/esp_aes.h"
#include "mbedtls/base64.h"
#define ESP_AES_ENCRYPT 1
esp_aes_context aes;
unsigned char key[33] = {'d', 'v', 'i', 'z', 'd', 'u', 'm', 'c', 's', 'm', 'v', 'l', 'v', 'f', 'd', 'v', 'b', 'j', 's', 'v', 'd', 'u', 'i', 'a', 's', 'r', 'u', 'i', 'a', 'e', 'u', 'y', '\0'};
unsigned char encoded[1024] = {0};
void crypto_aes_ecb(char *input){
static const char *TAG = "CryptTest";
bool doEncrypt = true;
uint16_t blockIndex = 0;
uint16_t inputIndex = 0;
uint16_t outputIndex = 0;
uint16_t encryptedLength = 0;
size_t encodedLength = 0;
unsigned char inputBlock[16] = {0};
unsigned char outputBlock[17] = {0};
unsigned char encrypted_raw[1024] = {0};
esp_aes_init(&aes);
esp_aes_setkey(&aes, (const unsigned char*) key, 256);
inputIndex = 0;
while(doEncrypt){
for (blockIndex = 0; blockIndex < 16; blockIndex++){
inputBlock[blockIndex] = input[blockIndex + (inputIndex * 16)];
if(input[blockIndex + (inputIndex * 16)] == '\0'){
for (; blockIndex < 16; blockIndex++){inputBlock[blockIndex] = '\0';}
doEncrypt = false;
break;
}
}
if(input[blockIndex + (inputIndex * 16)] == '\0'){doEncrypt = false;}
inputBlock[16] = '\0';
ESP_LOGI(TAG, "inputBlock = '%s'", inputBlock);
esp_aes_crypt_ecb(&aes, ESP_AES_ENCRYPT, (const unsigned char *)inputBlock, outputBlock);
for (blockIndex = 0; blockIndex < 16; blockIndex++){
encrypted_raw[blockIndex + (outputIndex * 16)] = outputBlock[blockIndex];
}
encryptedLength = blockIndex + (outputIndex * 16);
inputIndex++;
outputIndex++;
}
// encodedLength = mbedtls_base64_encode(encrypted_raw, encryptedLength, encoded, sizeof(encoded));
mbedtls_base64_encode((unsigned char*)encoded, sizeof(encoded), &encodedLength, encrypted_raw, encryptedLength);
encoded[encodedLength] = '\0';
ESP_LOGW(TAG, "-----------------------------------------------------------------------------------");
ESP_LOGI(TAG, "Key : '%s'", key);
ESP_LOGI(TAG, "Input : '%s'", input);
ESP_LOGI(TAG, "Output : '%s'", encoded);
esp_aes_free(&aes);
}
void app_main(){
crypto_aes_ecb("Testing encryption... Testing encryption...");
}
// --- PHP 侧 ---
<?php
$cryptoKey = "dvizdumcsmvlvfdvbjsvduiasruiaeuy";
$base64 = "6pnKOStiWM5xWnVi/qy38CkWDB4g9bpvsH7H7gvrOuOJUfSEl2FL6GYieHJgDz4t";
$intRes = openssl_decrypt($base64, 'AES-256-ECB', $cryptoKey, OPENSSL_ZERO_PADDING);
$decrypted = rtrim($intRes, "\0");
echo "<html>\n<body>\n";
echo "Key : '" . $cryptoKey . "'<br />\n";
echo "Input : '" . $base64 . "'<br />\n";
echo "Decrypted : '" . $decrypted . "'<br />\n";
echo "</body>\n</html>\n";
?>
英文:
So - my solution, if anyone wants a working example:
--- ESP32 side ---
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_system.h"
#include "esp_spi_flash.h"
#include "mbedtls/aes.h"
#include "esp_log.h"
#include "aes/esp_aes.h"
#include "mbedtls/base64.h"
#define ESP_AES_ENCRYPT 1
esp_aes_context aes;
unsigned char key[33] = {'d', 'v', 'i', 'z', 'd', 'u', 'm', 'c', 's', 'm', 'v', 'l', 'v', 'f', 'd', 'v', 'b', 'j', 's', 'v', 'd', 'u', 'i', 'a', 's', 'r', 'u', 'i', 'a', 'e', 'u', 'y', '\0'};
unsigned char encoded[1024] = {0};
void crypto_aes_ecb(char *input){
static const char *TAG = "CryptTest";
bool doEncrypt = true;
uint16_t blockIndex = 0;
uint16_t inputIndex = 0;
uint16_t outputIndex = 0;
uint16_t encryptedLength = 0;
size_t encodedLength = 0;
unsigned char inputBlock[16] = {0};
unsigned char outputBlock[17] = {0};
unsigned char encrypted_raw[1024] = {0};
esp_aes_init(&aes);
esp_aes_setkey(&aes, (const unsigned char*) key, 256);
inputIndex = 0;
while(doEncrypt){
for (blockIndex = 0; blockIndex < 16; blockIndex++){
inputBlock[blockIndex] = input[blockIndex + (inputIndex * 16)];
if(input[blockIndex + (inputIndex * 16)] == '\0'){
for (; blockIndex < 16; blockIndex++){inputBlock[blockIndex] = '\0';}
doEncrypt = false;
break;
}
}
if(input[blockIndex + (inputIndex * 16)] == '\0'){doEncrypt = false;}
inputBlock[16] = '\0';
ESP_LOGI(TAG, "inputBlock = '%s'", inputBlock);
esp_aes_crypt_ecb(&aes, ESP_AES_ENCRYPT, (const unsigned char *)inputBlock, outputBlock);
for (blockIndex = 0; blockIndex < 16; blockIndex++){
encrypted_raw[blockIndex + (outputIndex * 16)] = outputBlock[blockIndex];
}
encryptedLength = blockIndex + (outputIndex * 16);
inputIndex++;
outputIndex++;
}
// encodedLength = mbedtls_base64_encode(encrypted_raw, encryptedLength, encoded, sizeof(encoded));
mbedtls_base64_encode((unsigned char*)encoded, sizeof(encoded), &encodedLength, encrypted_raw, encryptedLength);
encoded[encodedLength] = '\0';
ESP_LOGW(TAG, "-----------------------------------------------------------------------------------");
ESP_LOGI(TAG, "Key : '%s'", key);
ESP_LOGI(TAG, "Input : '%s'", input);
ESP_LOGI(TAG, "Output : '%s'", encoded);
esp_aes_free(&aes);
}
void app_main(){
crypto_aes_ecb("Testing encryption... Testing encryption...");
}
--- Result ---
I (325) CryptTest: -----------------------------------------------------------------------------------
I (335) CryptTest: Key : 'dvizdumcsmvlvfdvbjsvduiasruiaeuy'
I (335) CryptTest: Input : 'Testing encryption... Testing encryption...'
I (345) CryptTest: Output : '6pnKOStiWM5xWnVi/qy38CkWDB4g9bpvsH7H7gvrOuOJUfSEl2FL6GYieHJgDz4t'
--- PHP side ---
<?php
$cryptoKey = "dvizdumcsmvlvfdvbjsvduiasruiaeuy";
$base64 = "6pnKOStiWM5xWnVi/qy38CkWDB4g9bpvsH7H7gvrOuOJUfSEl2FL6GYieHJgDz4t";
$intRes = openssl_decrypt($base64, 'AES-256-ECB', $cryptoKey, OPENSSL_ZERO_PADDING);
$decrypted = rtrim($intRes, "\0");
echo "<html>\n<body>\n";
echo "Key : '" . $cryptoKey . "'<br />\n";
echo "Input : '" . $base64 . "'<br />\n";
echo "Decrypted : '" . $decrypted . "'<br />\n";
echo "</body>\n</html>\n";
?>
--- Result ---
Key : 'dvizdumcsmvlvfdvbjsvduiasruiaeuy'
Input : '6pnKOStiWM5xWnVi/qy38CkWDB4g9bpvsH7H7gvrOuOJUfSEl2FL6GYieHJgDz4t'
Decrypted : 'Testing encryption... Testing encryption...'
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