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2.9 kB · 98 lines
C++
at master
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899#include "ObfuscationUtils.h"
#include <Logging.h>#include <base64.h>#include <esp_mac.h>#include <mbedtls/base64.h>
#include <cstring>
namespace obfuscation {
namespace {constexpr size_t HW_KEY_LEN = 6;
// Simple lazy init — no thread-safety concern on single-core ESP32-C3.const uint8_t* getHwKey() { static uint8_t key[HW_KEY_LEN] = {}; static bool initialized = false; if (!initialized) { esp_efuse_mac_get_default(key); initialized = true; } return key;}} // namespace
void xorTransform(std::string& data) { const uint8_t* key = getHwKey(); for (size_t i = 0; i < data.size(); i++) { data[i] ^= key[i % HW_KEY_LEN]; }}
void xorTransform(std::string& data, const uint8_t* key, size_t keyLen) { if (keyLen == 0 || key == nullptr) return; for (size_t i = 0; i < data.size(); i++) { data[i] ^= key[i % keyLen]; }}
String obfuscateToBase64(const std::string& plaintext) { if (plaintext.empty()) return ""; std::string temp = plaintext; xorTransform(temp); return base64::encode(reinterpret_cast<const uint8_t*>(temp.data()), temp.size());}
std::string deobfuscateFromBase64(const char* encoded, bool* ok) { if (encoded == nullptr || encoded[0] == '\0') { if (ok) *ok = false; return ""; } if (ok) *ok = true; size_t encodedLen = strlen(encoded); // First call: get required output buffer size size_t decodedLen = 0; int ret = mbedtls_base64_decode(nullptr, 0, &decodedLen, reinterpret_cast<const unsigned char*>(encoded), encodedLen); if (ret != 0 && ret != MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL) { LOG_ERR("OBF", "Base64 decode size query failed (ret=%d)", ret); if (ok) *ok = false; return ""; } std::string result(decodedLen, '\0'); ret = mbedtls_base64_decode(reinterpret_cast<unsigned char*>(&result[0]), decodedLen, &decodedLen, reinterpret_cast<const unsigned char*>(encoded), encodedLen); if (ret != 0) { LOG_ERR("OBF", "Base64 decode failed (ret=%d)", ret); if (ok) *ok = false; return ""; } result.resize(decodedLen); xorTransform(result); return result;}
void selfTest() { const char* testInputs[] = {"", "hello", "WiFi P@ssw0rd!", "a"}; bool allPassed = true; for (const char* input : testInputs) { String encoded = obfuscateToBase64(std::string(input)); std::string decoded = deobfuscateFromBase64(encoded.c_str()); if (decoded != input) { LOG_ERR("OBF", "FAIL: \"%s\" -> \"%s\" -> \"%s\"", input, encoded.c_str(), decoded.c_str()); allPassed = false; } } // Verify obfuscated form differs from plaintext String enc = obfuscateToBase64("test123"); if (enc == "test123") { LOG_ERR("OBF", "FAIL: obfuscated output identical to plaintext"); allPassed = false; } if (allPassed) { LOG_DBG("OBF", "Obfuscation self-test PASSED"); }}
} // namespace obfuscation