From 799fee5a686e8d6015aefd27bb6130f42e93de83 Mon Sep 17 00:00:00 2001
From: Andrew <realendermanch@gmail.com>
Date: Sun, 4 Jun 2023 16:32:05 +0300
Subject: [PATCH] QWORD upgrade, abstract NEXTNBITS()

---
 src/header.h |  3 ++-
 src/main.cpp | 17 ++++++++++-------
 src/xp.cpp   | 26 +++++++++++++-------------
 3 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/src/header.h b/src/header.h
index 978a2ef..919afdf 100644
--- a/src/header.h
+++ b/src/header.h
@@ -39,7 +39,8 @@
 #define FIELD_BITS_2003     512
 #define FIELD_BYTES_2003    64
 
-#define FIRSTNBITS(field, n)           ((field) & ((1ULL << (n)) - 1))
+#define NEXTNBITS(field, n, offset)    (((QWORD)field >> offset) & ((1ULL << (n)) - 1))
+#define FIRSTNBITS(field, n)           NEXTNBITS(field, n, 0)
 
 // Confirmation ID generator constants
 #define SUCCESS 0
diff --git a/src/main.cpp b/src/main.cpp
index dc2f804..1e5a9a4 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -124,15 +124,18 @@ int main(int argc, char *argv[]) {
     // generate a key
     BN_sub(privateKey, genOrder, privateKey);
     nRaw <<= 1;
+    int count = 0, total = 1000;
 
-    generateXPKey(eCurve, genPoint, genOrder, privateKey, nRaw, pKey);
-    print_product_key(pKey);
-    std::cout << std::endl << std::endl;
+    for (int i = 0; i < total; i++) {
+        generateXPKey(eCurve, genPoint, genOrder, privateKey, nRaw, pKey);
+        print_product_key(pKey);
+        std::cout << std::endl << std::endl;
 
-    // verify the key
-    if (!verifyXPKey(eCurve, genPoint, pubPoint, pKey)) {
-        std::cout << "Fail! Key is invalid." << std::endl;
+        // verify the key
+        count += verifyXPKey(eCurve, genPoint, pubPoint, pKey);
     }
 
+    std::cout << "Success count: " << std::dec << count << "/" << total << std::endl;
+
     return 0;
-}
\ No newline at end of file
+}
diff --git a/src/xp.cpp b/src/xp.cpp
index 14779f7..28f9ec5 100644
--- a/src/xp.cpp
+++ b/src/xp.cpp
@@ -18,7 +18,7 @@
 #include "header.h"
 
 /* Unpacks the Windows XP Product Key. */
-void unpackXP(DWORD (&pRaw)[4], DWORD &pSerial, DWORD &pHash, QWORD &pSignature) {
+void unpackXP(QWORD (&pRaw)[2], DWORD &pSerial, DWORD &pHash, QWORD &pSignature) {
 
     // We're assuming that the quantity of information within the product key is at most 114 bits.
     // log2(24^25) = 114.
@@ -27,18 +27,18 @@ void unpackXP(DWORD (&pRaw)[4], DWORD &pSerial, DWORD &pHash, QWORD &pSignature)
     pSerial = FIRSTNBITS(pRaw[0], 31);
 
     // Hash (e) = Bits [31..58] -> 28 bits
-    pHash = FIRSTNBITS(pRaw[1] << 1 | pRaw[0] >> 31, 28);
+    pHash = NEXTNBITS(pRaw[0], 28, 31);
 
     // Signature (s) = Bits [59..113] -> 55 bits
-    pSignature = (QWORD)pRaw[3] << (5 + 8 * sizeof(DWORD)) | (QWORD)pRaw[2] << 5 | pRaw[1] >> 27;
+    pSignature = FIRSTNBITS(pRaw[1], 51) << 5 | NEXTNBITS(pRaw[0], 5, 59);
 }
 
 /* Packs the Windows XP Product Key. */
-void packXP(DWORD (&pRaw)[4], DWORD pSerial, DWORD pHash, QWORD pSignature) {
-    pRaw[0] = pSerial | FIRSTNBITS(pHash, 1) << 31;
-    pRaw[1] = FIRSTNBITS(pSignature, 5) << 27 | pHash >> 1;
-    pRaw[2] = (DWORD)(pSignature >> 5);
-    pRaw[3] = (DWORD)(pSignature >> (5 + 8 * sizeof(DWORD)));
+void packXP(QWORD (&pRaw)[2], DWORD pSerial, DWORD pHash, QWORD pSignature) {
+    pRaw[0] = FIRSTNBITS(pSignature, 5) << 59 | FIRSTNBITS(pHash, 28) << 31 | pSerial;
+
+    // sig is 56 bits long, 5 of them are used -> 51 bits remaining
+    pRaw[1] = NEXTNBITS(pSignature, 51, 5);
 }
 
 /* Verify Product Key */
@@ -46,7 +46,7 @@ bool verifyXPKey(EC_GROUP *eCurve, EC_POINT *generator, EC_POINT *publicKey, cha
     BN_CTX *context = BN_CTX_new();
 
     // Convert Base24 CD-key to bytecode.
-    DWORD bKey[4]{};
+    QWORD bKey[2]{};
     DWORD pID, checkHash;
 
     QWORD sig = 0;
@@ -156,13 +156,13 @@ void generateXPKey(EC_GROUP *eCurve, EC_POINT *generator, BIGNUM *order, BIGNUM
     BIGNUM *x = BN_new();
     BIGNUM *y = BN_new();
 
-    DWORD bKey[4]{};
+    QWORD bKey[2]{};
 
     do {
         DWORD hash = 0;
         QWORD sig = 0;
 
-        memset(bKey, 0, 4);
+        memset(bKey, 0, 2 * sizeof(QWORD));
 
         // Generate a random number c consisting of 384 bits without any constraints.
         BN_rand(c, FIELD_BITS, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY);
@@ -235,9 +235,9 @@ void generateXPKey(EC_GROUP *eCurve, EC_POINT *generator, BIGNUM *order, BIGNUM
                   << " Sig: " << std::hex << std::setw(8) << std::setfill('0') << sig  << std::endl
                               << std::endl;
 
-    } while (bKey[3] >= 0x40000);
+    } while (bKey[1] >= (1ULL << 50));
     // ↑ ↑ ↑
-    // bKey[3] can't be longer than 18 bits, else the signature part will make
+    // bKey[1] can't be longer than 50 bits, else the signature part will make
     // the CD-key longer than 25 characters.
 
     // Convert the key to Base24.