Something went wrong. Try again.
A fork of https://github.com/crosspoint-reader/crosspoint-reader
Something went wrong. Try again.
3.4 kB · 111 lines
C++
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112#include "ObfuscationUtils.h"
#include <Logging.h>#include <base64.h>#include <esp_mac.h>#include <mbedtls/base64.h>
#include <array>#include <cstring>#include <limits>
namespace obfuscation {
namespace {constexpr size_t HW_KEY_LEN = 6;
const uint8_t* getHwKey() { // Function-local static initialization is synchronized by C++, including // on dual-core targets. The previous hand-rolled boolean could expose a // partially initialized key to another task. static const std::array<uint8_t, HW_KEY_LEN> key = [] { std::array<uint8_t, HW_KEY_LEN> value{}; esp_efuse_mac_get_default(value.data()); return value; }(); return key.data();}} // 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) { return deobfuscateFromBase64(encoded, std::numeric_limits<size_t>::max(), ok, nullptr);}
std::string deobfuscateFromBase64(const char* encoded, const size_t maxDecodedLength, bool* ok, bool* tooLong) { if (tooLong) *tooLong = false; 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 ""; } if (decodedLen > maxDecodedLength) { if (ok) *ok = false; if (tooLong) *tooLong = true; 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