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HW::AES: add generator_constant

This commit is contained in:
B3n30 2018-10-17 16:07:11 +02:00
parent c4ed7e75f4
commit 1849e8b09c
1 changed files with 10 additions and 12 deletions
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22
src/core/hw/aes/key.cpp
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@ -19,7 +19,14 @@ namespace AES {
namespace {
std::optional<AESKey> generator_constant;
// The generator constant was calculated using the 0x39 KeyX and KeyY retrieved from a 3DS and the
// normal key dumped from a Wii U solving the equation:
// NormalKey = (((KeyX ROL 2) XOR KeyY) + constant) ROL 87
// On a real 3DS the generation for the normal key is hardware based, and thus the constant can't
// get dumped . generated normal keys are also not accesible on a 3DS. The used formula for
// calculating the constant is a software implementation of what the hardware generator does.
constexpr AESKey generator_constant = {{0x1F, 0xF9, 0xE9, 0xAA, 0xC5, 0xFE, 0x04, 0x08, 0x02, 0x45,
0x91, 0xDC, 0x5D, 0x52, 0x76, 0x8A}};
struct KeyDesc {
char key_type;
@ -48,8 +55,8 @@ struct KeySlot {
}
void GenerateNormalKey() {
if (x && y && generator_constant) {
normal = Lrot128(Add128(Xor128(Lrot128(*x, 2), *y), *generator_constant), 87);
if (x && y) {
normal = Lrot128(Add128(Xor128(Lrot128(*x, 2), *y), generator_constant), 87);
} else {
normal = {};
}
@ -181,11 +188,6 @@ void LoadPresetKeys() {
continue;
}
if (name == "generator") {
generator_constant = key;
continue;
}
std::size_t common_key_index;
if (std::sscanf(name.c_str(), "common%zd", &common_key_index) == 1) {
if (common_key_index >= common_key_y_slots.size()) {
@ -236,10 +238,6 @@ void InitKeys() {
initialized = true;
}
void SetGeneratorConstant(const AESKey& key) {
generator_constant = key;
}
void SetKeyX(std::size_t slot_id, const AESKey& key) {
key_slots.at(slot_id).SetKeyX(key);
}