From f5423a8eb087551c2655204cb0723543046c2c05 Mon Sep 17 00:00:00 2001
From: Andrew <realendermanch@gmail.com>
Date: Thu, 1 Jun 2023 16:09:22 +0300
Subject: [PATCH] Refactor, improved readability

---
 .idea/misc.xml       |   8 +
 .idea/modules.xml    |   8 -
 CMakeLists.txt       |  27 +--
 cli.cpp              |  44 +++++
 header.h             |  76 ++++++++
 key.cpp              |  68 +++++++
 main.cpp             |  83 +++++++++
 server_algorithm.cpp |  95 +++++-----
 shared.cpp           | 102 ----------
 shared.h             |  54 ------
 util.cpp             |  14 ++
 xp_algorithm.cpp     | 433 ++++++++++++++++++++-----------------------
 12 files changed, 548 insertions(+), 464 deletions(-)
 delete mode 100644 .idea/modules.xml
 create mode 100644 cli.cpp
 create mode 100644 header.h
 create mode 100644 key.cpp
 create mode 100644 main.cpp
 delete mode 100644 shared.cpp
 delete mode 100644 shared.h
 create mode 100644 util.cpp

diff --git a/.idea/misc.xml b/.idea/misc.xml
index be0f224..0ee1767 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,5 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="CidrRootsConfiguration">
+    <sourceRoots>
+      <file path="$PROJECT_DIR$" />
+    </sourceRoots>
+    <libraryRoots>
+      <file path="$PROJECT_DIR$/lib" />
+    </libraryRoots>
+  </component>
   <component name="ExternalStorageConfigurationManager" enabled="true" />
   <component name="MakefileSettings">
     <option name="linkedExternalProjectsSettings">
diff --git a/.idea/modules.xml b/.idea/modules.xml
deleted file mode 100644
index c7712ed..0000000
--- a/.idea/modules.xml
+++ /dev/null
@@ -1,8 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ProjectModuleManager">
-    <modules>
-      <module fileurl="file://$PROJECT_DIR$/.idea/WindowsXPKg.iml" filepath="$PROJECT_DIR$/.idea/WindowsXPKg.iml" />
-    </modules>
-  </component>
-</project>
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 285f1e5..c405b80 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,30 +2,17 @@ CMAKE_MINIMUM_REQUIRED(VERSION 2.8.11)
 PROJECT(WindowsXPKg)
 SET(CMAKE_CXX_STANDARD 17)
 
-set(OPENSSL_USE_STATIC_LIBS TRUE)
-find_package(PkgConfig REQUIRED)
-pkg_search_module(OPENSSL REQUIRED openssl)
+FIND_PACKAGE(PkgConfig REQUIRED)
+PKG_SEARCH_MODULE(OPENSSL REQUIRED openssl)
 
-if (!OPENSSL_FOUND)
-    message(FATAL_ERROR "OpenSSL Development Libraries Not Found")
-endif()
+IF(!OPENSSL_FOUND)
+    MESSAGE(FATAL_ERROR "OpenSSL Not Found")
+ENDIF()
 
-# generate bink.h
-add_custom_command(
-        OUTPUT bink.h
-        COMMAND ${PROJECT_SOURCE_DIR}/convert_keys_to_cpp.py
-        WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
-        DEPENDS bink.h
-)
-
-set(BUILD_SHARED_LIBS OFF)
-set(CMAKE_EXE_LINKER_FLAGS "-static")
-ADD_EXECUTABLE(xpkey xp_algorithm.cpp shared.cpp bink.h)
+ADD_EXECUTABLE(xpkey xp_algorithm.cpp key.cpp)
 TARGET_INCLUDE_DIRECTORIES(xpkey PUBLIC crypto)
 TARGET_LINK_LIBRARIES(xpkey PUBLIC crypto)
-add_dependencies(xpkey bink.h)
 
-ADD_EXECUTABLE(srv2003key server_algorithm.cpp shared.cpp bink.h)
+ADD_EXECUTABLE(srv2003key server_algorithm.cpp key.cpp)
 TARGET_INCLUDE_DIRECTORIES(srv2003key PUBLIC crypto)
 TARGET_LINK_LIBRARIES(srv2003key PUBLIC crypto)
-add_dependencies(srv2003key bink.h)
diff --git a/cli.cpp b/cli.cpp
new file mode 100644
index 0000000..808dbbf
--- /dev/null
+++ b/cli.cpp
@@ -0,0 +1,44 @@
+//
+// Created by Andrew on 01/06/2023.
+//
+
+#include "header.h"
+
+void print_product_id(ul32 *pid)
+{
+    char raw[12];
+    char b[6], c[8];
+    int i, digit = 0;
+
+    //	Cut a away last bit of pid and convert it to an accii-number (=raw)
+    sprintf(raw, "%lu", pid[0] >> 1);
+
+    // Make b-part {640-....}
+    strncpy(b, raw, 3);
+    b[3] = 0;
+
+    // Make c-part {...-123456X...}
+    strcpy(c, raw + 3);
+    printf("> %s\n", c);
+
+    // Make checksum digit-part {...56X-}
+    assert(strlen(c) == 6);
+    for (i = 0; i < 6; i++)
+        digit -= c[i] - '0';	// Sum digits
+
+    while (digit < 0)
+        digit += 7;
+    c[6] = digit + '0';
+    c[7] = 0;
+
+    printf("Product ID: PPPPP-%s-%s-23xxx\n", b, c);
+}
+
+void print_product_key(char *pk) {
+    int i;
+    assert(strlen(pk) == 25);
+    for (i = 0; i < 25; i++) {
+        putchar(pk[i]);
+        if (i != 24 && i % 5 == 4) putchar('-');
+    }
+}
\ No newline at end of file
diff --git a/header.h b/header.h
new file mode 100644
index 0000000..e29356a
--- /dev/null
+++ b/header.h
@@ -0,0 +1,76 @@
+//
+// Created by neo on 5/26/2023.
+//
+
+#ifndef WINDOWSXPKG_HEADER_H
+#define WINDOWSXPKG_HEADER_H
+
+#include <cassert>
+#include <cstdio>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <ctime>
+#include <string>
+#include <vector>
+#include <unordered_map>
+
+#include <openssl/bn.h>
+#include <openssl/ec.h>
+#include <openssl/sha.h>
+#include <openssl/rand.h>
+
+#define PK_LENGTH           25
+#define NULL_TERMINATOR     1
+
+#define FIELD_BITS          384
+#define FIELD_BYTES         48
+#define FIELD_BITS_2003     512
+#define FIELD_BYTES_2003    64
+
+typedef unsigned char byte;
+typedef unsigned long ul32;
+
+extern char charset[];
+
+// util.cpp
+void endian(byte *data, int length);
+
+// key.cpp
+void unbase24(ul32 *byteSeq, char *cdKey);
+void base24(char *cdKey, ul32 *byteSeq);
+
+// cli.cpp
+void print_product_key(char *pk);
+void print_product_id(ul32 *pid);
+
+// xp.cpp
+bool verifyXPKey(EC_GROUP *eCurve, EC_POINT *generator, EC_POINT *publicKey, char *cdKey);
+void generateXPKey(char *pKey, EC_GROUP *eCurve, EC_POINT *generator, BIGNUM *order, BIGNUM *privateKey, ul32 *pRaw);
+
+// server.cpp
+
+struct ECDLP_Params {
+    //         p,           a,           b
+    std::tuple<std::string, std::string, std::string> E;
+
+    //         x,           y
+    std::tuple<std::string, std::string> K;
+
+    //         x,           y
+    std::tuple<std::string, std::string> G;
+
+    std::string n;
+    std::string k;
+};
+
+struct ProductID {
+    uint8_t SiteID;
+    uint16_t Serial;
+};
+
+extern std::unordered_map<std::string, std::unordered_map<int, std::string>> Products;
+extern std::unordered_map<std::string, ECDLP_Params> BINKData;
+void initBink();
+
+#endif //WINDOWSXPKG_HEADER_H
diff --git a/key.cpp b/key.cpp
new file mode 100644
index 0000000..fb2b83c
--- /dev/null
+++ b/key.cpp
@@ -0,0 +1,68 @@
+//
+// Created by neo on 5/26/2023.
+//
+
+#include "header.h"
+
+/* Converts from CD-key to a byte sequence. */
+void unbase24(ul32 *byteSeq, const char *cdKey) {
+    byte pDecodedKey[PK_LENGTH + NULL_TERMINATOR]{};
+    BIGNUM *y = BN_new();
+
+    BN_zero(y);
+
+    // Remove dashes from the CD-key and put it into a Base24 byte array.
+    for (int i = 0, k = 0; i < strlen(cdKey) && k < PK_LENGTH; i++) {
+        for (int j = 0; j < 24; j++) {
+            if (cdKey[i] != '-' && cdKey[i] == charset[j]) {
+                pDecodedKey[k++] = j;
+                break;
+            }
+        }
+    }
+
+    // Empty byte sequence.
+    memset(byteSeq, 0, 16);
+
+    // Calculate the weighed sum of byte array elements.
+    for (int i = 0; i < PK_LENGTH; i++) {
+        BN_mul_word(y, PK_LENGTH - 1);
+        BN_add_word(y, pDecodedKey[i]);
+    }
+
+    // Acquire length.
+    int n = BN_num_bytes(y);
+
+    // Place the generated code into the byte sequence.
+    BN_bn2bin(y, (byte *)byteSeq);
+    BN_free(y);
+
+    // Reverse the byte sequence.
+    endian((byte *) byteSeq, n);
+}
+
+/* Converts from byte sequence to the CD-key. */
+void base24(char *cdKey, ul32 *byteSeq) {
+    byte rbyteSeq[16];
+    BIGNUM *z;
+
+    // Copy byte sequence to the reversed byte sequence.
+    memcpy(rbyteSeq, byteSeq, sizeof(rbyteSeq));
+
+    // Skip trailing zeroes and reverse y.
+    int length;
+
+    for (length = 15; rbyteSeq[length] == 0; length--);
+    endian(rbyteSeq, ++length);
+
+    // Convert reversed byte sequence to BigNum z.
+    z = BN_bin2bn(rbyteSeq, length, nullptr);
+
+    // Divide z by 24 and convert the remainder to a CD-key char.
+    cdKey[25] = 0;
+
+    for (int i = 24; i >= 0; i--)
+        cdKey[i] = charset[BN_div_word(z, 24)];
+
+    BN_free(z);
+}
\ No newline at end of file
diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..0dbe375
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,83 @@
+//
+// Created by Andrew on 01/06/2023.
+//
+
+#include "header.h"
+
+char charset[] = "BCDFGHJKMPQRTVWXY2346789";
+
+int main()
+{
+    initBink();
+
+    rand();
+    srand(time(nullptr));
+    rand();
+
+    // Init
+    BIGNUM *a, *b, *p, *gx, *gy, *pubx, *puby, *n, *priv;
+    BN_CTX *ctx = BN_CTX_new();
+
+    // make BigNumbers
+    a = BN_new();
+    b = BN_new();
+    p = BN_new();
+    gx = BN_new();
+    gy = BN_new();
+    pubx = BN_new();
+    puby = BN_new();
+    n = BN_new();
+    priv = BN_new();
+
+    char* BINKID = "2E";
+
+    // Data from pidgen-Bink-resources
+    /* Elliptic curve parameters: y^2 = x^3 + ax + b mod p */
+    BN_dec2bn(&p,    std::get<0>(BINKData[BINKID].E).c_str());
+    BN_dec2bn(&a,    std::get<1>(BINKData[BINKID].E).c_str());
+    BN_dec2bn(&b,    std::get<2>(BINKData[BINKID].E).c_str());
+
+
+    /* base point (generator) G */
+    BN_dec2bn(&gx,   std::get<0>(BINKData[BINKID].G).c_str());
+    BN_dec2bn(&gy,   std::get<1>(BINKData[BINKID].G).c_str());
+
+    /* inverse of public key */
+    BN_dec2bn(&pubx, std::get<0>(BINKData[BINKID].K).c_str());
+    BN_dec2bn(&puby, std::get<1>(BINKData[BINKID].K).c_str());
+
+    // Computed data
+    /* order of G - computed in 18 hours using a P3-450 */
+    BN_dec2bn(&n,    BINKData[BINKID].n.c_str());
+
+    /* THE private key  - computed in 10 hours using a P3-450 */
+    BN_dec2bn(&priv, BINKData[BINKID].k.c_str());
+
+    // Calculation
+    EC_GROUP *ec = EC_GROUP_new_curve_GFp(p, a, b, ctx);
+    EC_POINT *g = EC_POINT_new(ec);
+    EC_POINT_set_affine_coordinates_GFp(ec, g, gx, gy, ctx);
+    EC_POINT *pub = EC_POINT_new(ec);
+    EC_POINT_set_affine_coordinates_GFp(ec, pub, pubx, puby, ctx);
+
+    char pkey[26];
+    ul32 pid[1];
+    pid[0] = 640 * 1000000 ; /* <- change */
+    pid[0] += rand() & 999999;
+
+    printf("> PID: %lu\n", pid[0]);
+
+    // generate a key
+    BN_sub(priv, n, priv);
+    generateXPKey(pkey, ec, g, n, priv, pid);
+    print_product_key(pkey);
+    printf("\n\n");
+
+    // verify the key
+    verifyXPKey(ec, g, pub, (char*)pkey);
+
+    // Cleanup
+    BN_CTX_free(ctx);
+
+    return 0;
+}
\ No newline at end of file
diff --git a/server_algorithm.cpp b/server_algorithm.cpp
index acf5818..e5bd315 100644
--- a/server_algorithm.cpp
+++ b/server_algorithm.cpp
@@ -1,10 +1,6 @@
-#include "shared.h"
-#include "bink.h"
+#include "header.h"
 
-#define FIELD_BITS_2003 512
-#define FIELD_BYTES_2003 64
-
-void unpack2003(uint32_t *osfamily, uint32_t *hash, uint32_t *sig, uint32_t *prefix, uint32_t *raw)
+void unpack2003(ul32 *osfamily, ul32 *hash, ul32 *sig, ul32 *prefix, ul32 *raw)
 {
 	osfamily[0] = raw[0] & 0x7ff;
 	hash[0] = ((raw[0] >> 11) | (raw[1] << 21)) & 0x7fffffff;
@@ -13,7 +9,7 @@ void unpack2003(uint32_t *osfamily, uint32_t *hash, uint32_t *sig, uint32_t *pre
 	prefix[0] = (raw[3] >> 8) & 0x3ff;
 }
 
-void pack2003(uint32_t *raw, uint32_t *osfamily, uint32_t *hash, uint32_t *sig, uint32_t *prefix)
+void pack2003(ul32 *raw, ul32 *osfamily, ul32 *hash, ul32 *sig, ul32 *prefix)
 {
 	raw[0] = osfamily[0] | (hash[0] << 11);
 	raw[1] = (hash[0] >> 21) | (sig[0] << 10);
@@ -23,12 +19,12 @@ void pack2003(uint32_t *raw, uint32_t *osfamily, uint32_t *hash, uint32_t *sig,
 
 int verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cdkey)
 {
-	uint8_t key[25];
+	char key[25];
 	BN_CTX *ctx = BN_CTX_new();
 
 	for (int i = 0, k = 0; i < strlen(cdkey); i++) {
 		for (int j = 0; j < 24; j++) {
-			if (cdkey[i] != '-' && cdkey[i] == cset[j]) {
+			if (cdkey[i] != '-' && cdkey[i] == charset[j]) {
 				key[k++] = j;
 				break;
 			}
@@ -37,16 +33,18 @@ int verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cd
 		if (k >= 25) break;
 	}
 	
-	uint32_t bkey[4] = {0};
-	uint32_t osfamily[1], hash[1], sig[2], prefix[1];
+	ul32 bkey[4] = {0};
+	ul32 osfamily[1], hash[1], sig[2], prefix[1];
+
 	unbase24(bkey, key);
-	printf("%.8x %.8x %.8x %.8x\n", bkey[3], bkey[2], bkey[1], bkey[0]);
+
+	printf("%.8lx %.8lx %.8lx %.8lx\n", bkey[3], bkey[2], bkey[1], bkey[0]);
 	unpack2003(osfamily, hash, sig, prefix, bkey);
 	
-	printf("OS Family: %u\nHash: %.8x\nSig: %.8x %.8x\nPrefix: %.8x\n", osfamily[0], hash[0], sig[1], sig[0], prefix[0]);
+	printf("OS Family: %lu\nHash: %.8lx\nSig: %.8lx %.8lx\nPrefix: %.8lx\n", osfamily[0], hash[0], sig[1], sig[0], prefix[0]);
 	
-	uint8_t buf[FIELD_BYTES_2003], md[20];
-	uint32_t h1[2];
+	byte buf[FIELD_BYTES_2003], md[20];
+	ul32 h1[2];
 	SHA_CTX h_ctx;
 	
 	/* h1 = SHA-1(5D || OS Family || Hash || Prefix || 00 00) */
@@ -66,26 +64,26 @@ int verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cd
 	h1[0] = md[0] | (md[1] << 8) | (md[2] << 16) | (md[3] << 24);
 	h1[1] = (md[4] | (md[5] << 8) | (md[6] << 16) | (md[7] << 24)) >> 2;
 	h1[1] &= 0x3FFFFFFF;
-	printf("h1: %.8x %.8x\n", h1[1], h1[0]);
+	printf("h1: %.8lx %.8lx\n", h1[1], h1[0]);
 	
 	BIGNUM *s, *h, *x, *y;
 	x = BN_new();
 	y = BN_new();
-	endian((uint8_t *)sig, 8);
-	endian((uint8_t *)h1, 8);
-	s = BN_bin2bn((uint8_t *)sig, 8, NULL);
-	h = BN_bin2bn((uint8_t *)h1, 8, NULL);
+	endian((byte *)sig, 8);
+	endian((byte *)h1, 8);
+	s = BN_bin2bn((byte *)sig, 8, nullptr);
+	h = BN_bin2bn((byte *)h1, 8, nullptr);
 
 	EC_POINT *r = EC_POINT_new(ec);
 	EC_POINT *t = EC_POINT_new(ec);
 	/* r = sig*(sig*generator + h1*public_key) */
-	EC_POINT_mul(ec, t, NULL, generator, s, ctx);
-	EC_POINT_mul(ec, r, NULL, public_key, h, ctx);
+	EC_POINT_mul(ec, t, nullptr, generator, s, ctx);
+	EC_POINT_mul(ec, r, nullptr, public_key, h, ctx);
 	EC_POINT_add(ec, r, r, t, ctx);
-	EC_POINT_mul(ec, r, NULL, r, s, ctx);
-	EC_POINT_get_affine_coordinates_GFp(ec, r, x, y, ctx);
+	EC_POINT_mul(ec, r, nullptr, r, s, ctx);
+	EC_POINT_get_affine_coordinates(ec, r, x, y, ctx);
 	
-	uint32_t h2[1];
+	ul32 h2[1];
 	/* h2 = SHA-1(79 || OS Family || r.x || r.y) */
 	SHA1_Init(&h_ctx);
 	buf[0] = 0x79;
@@ -95,17 +93,17 @@ int verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cd
 	
 	memset(buf, 0, FIELD_BYTES_2003);
 	BN_bn2bin(x, buf);
-	endian((uint8_t *)buf, FIELD_BYTES_2003);
+	endian((byte *)buf, FIELD_BYTES_2003);
 	SHA1_Update(&h_ctx, buf, FIELD_BYTES_2003);
 	
 	memset(buf, 0, FIELD_BYTES_2003);
 	BN_bn2bin(y, buf);
-	endian((uint8_t *)buf, FIELD_BYTES_2003);
+	endian((byte *)buf, FIELD_BYTES_2003);
 	SHA1_Update(&h_ctx, buf, FIELD_BYTES_2003);
 	
 	SHA1_Final(md, &h_ctx);
 	h2[0] = (md[0] | (md[1] << 8) | (md[2] << 16) | (md[3] << 24)) & 0x7fffffff;
-	printf("Calculated hash: %.8x\n", h2[0]);
+	printf("Calculated hash: %.8lx\n", h2[0]);
 	
 	BN_free(s);
 	BN_free(h);
@@ -125,7 +123,7 @@ int verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cd
 	}
 }
 
-void generate2003(uint8_t *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BIGNUM *priv, uint32_t *osfamily, uint32_t *prefix)
+void generate2003(char *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BIGNUM *priv, ul32 *osfamily, ul32 *prefix)
 {
 	BN_CTX *ctx = BN_CTX_new();
 
@@ -136,17 +134,17 @@ void generate2003(uint8_t *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *orde
 	BIGNUM *b = BN_new();
 	EC_POINT *r = EC_POINT_new(ec);
 
-	uint32_t bkey[4];
-	uint8_t buf[FIELD_BYTES_2003], md[20];
-	uint32_t h1[2];
-	uint32_t hash[1], sig[2];
+	ul32 bkey[4];
+	byte buf[FIELD_BYTES_2003], md[20];
+	ul32 h1[2];
+	ul32 hash[1], sig[2];
 	
 	SHA_CTX h_ctx;
 	
 	for (;;) {
 		/* r = k*generator */
 		BN_pseudo_rand(k, FIELD_BITS_2003, -1, 0);
-		EC_POINT_mul(ec, r, NULL, generator, k, ctx);
+		EC_POINT_mul(ec, r, nullptr, generator, k, ctx);
 		EC_POINT_get_affine_coordinates_GFp(ec, r, x, y, ctx);
 			
 		/* hash = SHA-1(79 || OS Family || r.x || r.y) */
@@ -158,12 +156,12 @@ void generate2003(uint8_t *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *orde
 		
 		memset(buf, 0, FIELD_BYTES_2003);
 		BN_bn2bin(x, buf);
-		endian((uint8_t *)buf, FIELD_BYTES_2003);
+		endian((byte *)buf, FIELD_BYTES_2003);
 		SHA1_Update(&h_ctx, buf, FIELD_BYTES_2003);
 		
 		memset(buf, 0, FIELD_BYTES_2003);
 		BN_bn2bin(y, buf);
-		endian((uint8_t *)buf, FIELD_BYTES_2003);
+		endian((byte *)buf, FIELD_BYTES_2003);
 		SHA1_Update(&h_ctx, buf, FIELD_BYTES_2003);
 		
 		SHA1_Final(md, &h_ctx);
@@ -186,11 +184,11 @@ void generate2003(uint8_t *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *orde
 		h1[0] = md[0] | (md[1] << 8) | (md[2] << 16) | (md[3] << 24);
 		h1[1] = (md[4] | (md[5] << 8) | (md[6] << 16) | (md[7] << 24)) >> 2;
 		h1[1] &= 0x3FFFFFFF;
-		printf("h1: %.8x %.8x\n", h1[1], h1[0]);
+		printf("h1: %.8lx %.8lx\n", h1[1], h1[0]);
 	
 		/* s = ( -h1*priv + sqrt( (h1*priv)^2 + 4k ) ) / 2 */
-		endian((uint8_t *)h1, 8);
-		BN_bin2bn((uint8_t *)h1, 8, b);
+		endian((byte *)h1, 8);
+		BN_bin2bn((byte *)h1, 8, b);
 		BN_mod_mul(b, b, priv, order, ctx);
 		BN_copy(s, b);
 		BN_mod_sqr(s, s, order, ctx);
@@ -203,14 +201,15 @@ void generate2003(uint8_t *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *orde
 		}
 		BN_rshift1(s, s);
 		sig[0] = sig[1] = 0;
-		BN_bn2bin(s, (uint8_t *)sig);
-		endian((uint8_t *)sig, BN_num_bytes(s));
+		BN_bn2bin(s, (byte *)sig);
+		endian((byte *)sig, BN_num_bytes(s));
 		if (sig[1] < 0x40000000) break;
 	}
 	pack2003(bkey, osfamily, hash, sig, prefix);
-	printf("OS family: %u\nHash: %.8x\nSig: %.8x %.8x\nPrefix: %.8x\n", osfamily[0], hash[0], sig[1], sig[0], prefix[0]);
-	printf("%.8x %.8x %.8x %.8x\n", bkey[3], bkey[2], bkey[1], bkey[0]);
-	base24(pkey, bkey);
+	printf("OS family: %lu\nHash: %.8lx\nSig: %.8lx %.8lx\nPrefix: %.8lx\n", osfamily[0], hash[0], sig[1], sig[0], prefix[0]);
+	printf("%.8lx %.8lx %.8lx %.8lx\n", bkey[3], bkey[2], bkey[1], bkey[0]);
+
+    base24(pkey, bkey);
 	
 	BN_free(k);
 	BN_free(s);
@@ -223,7 +222,7 @@ void generate2003(uint8_t *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *orde
 	
 }
 
-int main()
+int gen2003()
 {
 	BIGNUM *a, *b, *p, *gx, *gy, *pubx, *puby, *n, *priv;
 	BN_CTX *ctx = BN_CTX_new();
@@ -259,11 +258,11 @@ int main()
 	assert(EC_POINT_is_on_curve(ec, g, ctx) == 1);
 	assert(EC_POINT_is_on_curve(ec, pub, ctx) == 1);
 	
-	uint8_t pkey[25];
-	uint32_t osfamily[1], prefix[1];
+	char pkey[25];
+	ul32 osfamily[1], prefix[1];
 	
 	osfamily[0] = 1280;
-	RAND_pseudo_bytes((uint8_t *)prefix, 4);
+	RAND_pseudo_bytes((byte *)prefix, 4);
 	prefix[0] &= 0x3ff;
 	
 	do {
diff --git a/shared.cpp b/shared.cpp
deleted file mode 100644
index 0dcb564..0000000
--- a/shared.cpp
+++ /dev/null
@@ -1,102 +0,0 @@
-//
-// Created by neo on 5/26/2023.
-//
-
-#include "shared.h"
-
-uint8_t cset[] = "BCDFGHJKMPQRTVWXY2346789";
-
-// Reverse data
-void endian(uint8_t *data, int len)
-{
-    int i;
-    for (i = 0; i < len/2; i++) {
-        uint8_t temp;
-        temp = data[i];
-        data[i] = data[len-i-1];
-        data[len-i-1] = temp;
-    }
-}
-
-void unbase24(uint32_t *x, uint8_t *c)
-{
-    memset(x, 0, 16);
-    int i, n;
-
-    BIGNUM *y = BN_new();
-    BN_zero(y);
-
-    for (i = 0; i < 25; i++)
-    {
-        BN_mul_word(y, 24);
-        BN_add_word(y, c[i]);
-    }
-
-    n = BN_num_bytes(y);
-    BN_bn2bin(y, (uint8_t *)x);
-    BN_free(y);
-
-    endian((uint8_t *)x, n);
-}
-
-void base24(uint8_t *c, uint32_t *x)
-{
-    uint8_t y[16];
-    int i;
-    BIGNUM *z;
-
-    // Convert x to BigNum z
-    memcpy(y, x, sizeof(y));				// Copy X to Y; Y=X
-    for (i = 15; y[i] == 0; i--) {} i++;	// skip following nulls
-    endian(y, i);							// Reverse y
-    z = BN_bin2bn(y, i, NULL);				// Convert y to BigNum z
-
-    // Divide z by 24 and convert remainder with cset to Base24-CDKEY Char
-    c[25] = 0;
-    for (i = 24; i >= 0; i--) {
-        uint8_t t = BN_div_word(z, 24);
-        c[i] = cset[t];
-    }
-
-    BN_free(z);
-}
-
-void print_product_id(uint32_t *pid)
-{
-    char raw[12];
-    char b[6], c[8];
-    int i, digit = 0;
-
-    //	Cut a away last bit of pid and convert it to an accii-number (=raw)
-    sprintf(raw, "%d", pid[0] >> 1);
-
-    // Make b-part {640-....}
-    strncpy(b, raw, 3);
-    b[3] = 0;
-
-    // Make c-part {...-123456X...}
-    strcpy(c, raw + 3);
-    printf("> %s\n", c);
-
-    // Make checksum digit-part {...56X-}
-    assert(strlen(c) == 6);
-    for (i = 0; i < 6; i++)
-        digit -= c[i] - '0';	// Sum digits
-
-    while (digit < 0)
-        digit += 7;
-    c[6] = digit + '0';
-    c[7] = 0;
-
-    printf("Product ID: PPPPP-%s-%s-23xxx\n", b, c);
-}
-
-void print_product_key(uint8_t *pk)
-{
-    int i;
-    assert(strlen((const char *)pk) == 25);
-    for (i = 0; i < 25; i++) {
-        putchar(pk[i]);
-        if (i != 24 && i % 5 == 4) putchar('-');
-    }
-}
\ No newline at end of file
diff --git a/shared.h b/shared.h
deleted file mode 100644
index a93302b..0000000
--- a/shared.h
+++ /dev/null
@@ -1,54 +0,0 @@
-//
-// Created by neo on 5/26/2023.
-//
-
-#ifndef WINDOWSXPKG_SHARED_H
-#define WINDOWSXPKG_SHARED_H
-
-#include <assert.h>
-#include <stdio.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-#include <string>
-#include <vector>
-#include <unordered_map>
-
-#include <openssl/bn.h>
-#include <openssl/ec.h>
-#include <openssl/sha.h>
-#include <openssl/rand.h>
-
-extern uint8_t cset[];
-
-void endian(uint8_t *data, int len);
-void unbase24(uint32_t *x, uint8_t *c);
-void base24(uint8_t *c, uint32_t *x);
-void print_product_key(uint8_t *pk);
-void print_product_id(uint32_t *pid);
-
-struct ECDLP_Params {
-    //         p,           a,           b
-    std::tuple<std::string, std::string, std::string> E;
-
-    //         x,           y
-    std::tuple<std::string, std::string> K;
-
-    //         x,           y
-    std::tuple<std::string, std::string> G;
-
-    std::string n;
-    std::string k;
-};
-
-struct ProductID {
-    uint8_t SiteID;
-    uint16_t Serial;
-};
-
-extern std::unordered_map<std::string, std::unordered_map<int, std::string>> Products;
-extern std::unordered_map<std::string, ECDLP_Params> BINKData;
-void initBink();
-
-#endif //WINDOWSXPKG_SHARED_H
diff --git a/util.cpp b/util.cpp
new file mode 100644
index 0000000..e73f8b4
--- /dev/null
+++ b/util.cpp
@@ -0,0 +1,14 @@
+//
+// Created by Andrew on 01/06/2023.
+//
+
+#include "header.h"
+
+/* Convert data between endianness types. */
+void endian(byte *data, int length) {
+    for (int i = 0; i < length / 2; i++) {
+        byte temp = data[i];
+        data[i] = data[length - i - 1];
+        data[length - i - 1] = temp;
+    }
+}
diff --git a/xp_algorithm.cpp b/xp_algorithm.cpp
index 6656499..ca92e12 100644
--- a/xp_algorithm.cpp
+++ b/xp_algorithm.cpp
@@ -15,265 +15,234 @@
 
 */
 
-#include "shared.h"
-#include "bink.h"
+#include "header.h"
 
-#define FIELD_BITS 384
-#define FIELD_BYTES 48
+/* Unpacks the Windows XP Product Key. */
+void unpackXP(ul32 *serial, ul32 *hash, ul32 *sig, ul32 *raw) {
 
+    // We're assuming that the quantity of information within the product key is at most 114 bits.
+    // log2(24^25) = 114.
 
-static void unpack(uint32_t *pid, uint32_t *hash, uint32_t *sig, uint32_t *raw)
-{
- // pid = Bit 0..30 
-	pid[0] = raw[0] & 0x7fffffff;
- 
- // hash(s) = Bit 31..58
-	hash[0] = ((raw[0] >> 31) | (raw[1] << 1)) & 0xfffffff;
- 
- // sig(e) = bit 58..113
-	sig[0] = (raw[1] >> 27) | (raw[2] << 5);
-	sig[1] = (raw[2] >> 27) | (raw[3] << 5);
+    // Serial = Bits [0..30] -> 31 bits
+    if (serial)
+        serial[0] = raw[0] & 0x7fffffff;
+
+    // Hash (e) = Bits [31..58] -> 28 bits
+    if (hash)
+        hash[0] = ((raw[0] >> 31) | (raw[1] << 1)) & 0xfffffff;
+
+    // Signature (s) = Bits [59..113] -> 55 bits
+    if (sig) {
+        sig[0] = (raw[1] >> 27) | (raw[2] << 5);
+        sig[1] = (raw[2] >> 27) | (raw[3] << 5);
+    }
 }
 
-static void pack(uint32_t *raw, uint32_t *pid, uint32_t *hash, uint32_t *sig)
-{
-	raw[0] = pid[0] | ((hash[0] & 1) << 31);
-	raw[1] = (hash[0] >> 1) | ((sig[0] & 0x1f) << 27);
-	raw[2] = (sig[0] >> 5) | (sig[1] << 27);
-	raw[3] = sig[1] >> 5;
+/* Packs the Windows XP Product Key. */
+void packXP(ul32 *raw, const ul32 *serial, const ul32 *hash, const ul32 *sig) {
+    raw[0] = serial[0] | ((hash[0] & 1) << 31);
+    raw[1] = (hash[0] >> 1) | ((sig[0] & 0x1f) << 27);
+    raw[2] = (sig[0] >> 5) | (sig[1] << 27);
+    raw[3] = sig[1] >> 5;
 }
 
-void verify(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cdkey)
-{
-	uint8_t key[25];
-	int i, j, k;
+/* Verify Product Key */
+bool verifyXPKey(EC_GROUP *eCurve, EC_POINT *generator, EC_POINT *publicKey, char *cdKey) {
+    BN_CTX *context = BN_CTX_new();
 
-	BN_CTX *ctx = BN_CTX_new();
-// remove Dashs from CDKEY
-	for (i = 0, k = 0; i < strlen(cdkey); i++) {
-		for (j = 0; j < 24; j++) {
-			if (cdkey[i] != '-' && cdkey[i] == cset[j]) {
-				key[k++] = j;
-				break;
-			}
-			assert(j < 24);
-		}
-		if (k >= 25) break;
-	}
-	
- // Base24_CDKEY -> Bin_CDKEY
-	uint32_t bkey[4] = {0};
-	uint32_t pid[1], hash[1], sig[2];
-	unbase24(bkey, key);
- 
- // Output Bin_CDKEY
-	printf("%.8x %.8x %.8x %.8x\n", bkey[3], bkey[2], bkey[1], bkey[0]);
+    // Convert Base24 CD-key to bytecode.
+    ul32 bKey[4]{};
+    ul32 pID, checkHash, sig[2];
 
- // Divide/Extract pid_data, hash, sig  from Bin_CDKEY
-	unpack(pid, hash, sig, bkey);
-	print_product_id(pid);
-	
-	printf("PID: %.8x\nHash: %.8x\nSig: %.8x %.8x\n", pid[0], hash[0], sig[1], sig[0]);
+    unbase24(bKey, cdKey);
 
-	
-	BIGNUM *e, *s;
-	
-	/* e = hash, s = sig */
-	e = BN_new();
-	BN_set_word(e, hash[0]);
-	endian((uint8_t *)sig, sizeof(sig));
-	s = BN_bin2bn((uint8_t *)sig, sizeof(sig), NULL);
-	
-	BIGNUM *x = BN_new();
-	BIGNUM *y = BN_new();
-	EC_POINT *u = EC_POINT_new(ec);
-	EC_POINT *v = EC_POINT_new(ec);
-	
-	/* v = s*generator + e*(-public_key) */
-	EC_POINT_mul(ec, u, NULL, generator, s, ctx);
-	EC_POINT_mul(ec, v, NULL, public_key, e, ctx);
-	EC_POINT_add(ec, v, u, v, ctx);
-	EC_POINT_get_affine_coordinates_GFp(ec, v, x, y, ctx);
-	
-	uint8_t buf[FIELD_BYTES], md[20];
-	uint32_t h;
-	uint8_t t[4];
-	SHA_CTX h_ctx;
-	
-	/* h = (fist 32 bits of SHA1(pid || v.x, v.y)) >> 4 */
-	SHA1_Init(&h_ctx);
-	t[0] =  pid[0] & 0xff;
-	t[1] = (pid[0] & 0xff00) >> 8;
-	t[2] = (pid[0] & 0xff0000) >> 16;
-	t[3] = (pid[0] & 0xff000000) >> 24;
-	SHA1_Update(&h_ctx, t, sizeof(t));
-	
-	memset(buf, 0, sizeof(buf));
-	BN_bn2bin(x, buf);
-	endian((uint8_t *)buf, sizeof(buf));
-	SHA1_Update(&h_ctx, buf, sizeof(buf));
-	
-	memset(buf, 0, sizeof(buf));
-	BN_bn2bin(y, buf);
-	endian((uint8_t *)buf, sizeof(buf));
-	SHA1_Update(&h_ctx, buf, sizeof(buf));
-	
-	SHA1_Final(md, &h_ctx);
-	h = (md[0] | (md[1] << 8) | (md[2] << 16) | (md[3] << 24)) >> 4;
-	h &= 0xfffffff;
-	
-	printf("Calculated hash: %.8x\n", h);
-	if (h == hash[0]) printf("Key valid\n");
-	else printf("Key invalid\n");
-	putchar('\n');
-	
-	BN_free(e);
-	BN_free(s);
-	BN_free(x);
-	BN_free(y);
-	EC_POINT_free(u);
-	EC_POINT_free(v);
+    // Extract data, hash and signature from the bytecode.
+    unpackXP(&pID, &checkHash, sig, bKey);
 
-	BN_CTX_free(ctx);
+    // e = Hash
+    // s = Signature
+    BIGNUM *e, *s;
+
+    // Put hash word into BigNum e.
+    e = BN_new();
+    BN_set_word(e, checkHash);
+
+    // Reverse signature and create a new BigNum s.
+    endian((byte *)sig, sizeof(sig));
+    s = BN_bin2bn((byte *)sig, sizeof(sig), nullptr);
+
+    // Create x and y.
+    BIGNUM *x = BN_new();
+    BIGNUM *y = BN_new();
+
+    // Create 2 new points on the existing elliptic curve.
+    EC_POINT *u = EC_POINT_new(eCurve);
+    EC_POINT *v = EC_POINT_new(eCurve);
+
+    // EC_POINT_mul calculates r = generator * n + q * m.
+    // v = s * generator + e * (-publicKey)
+
+    // u = generator * s
+    EC_POINT_mul(eCurve, u, nullptr, generator, s, context);
+
+    // v = publicKey * e
+    EC_POINT_mul(eCurve, v, nullptr, publicKey, e, context);
+
+    // v += u
+    EC_POINT_add(eCurve, v, u, v, context);
+
+    // EC_POINT_get_affine_coordinates() sets x and y, either of which may be nullptr, to the corresponding coordinates of p.
+    // x = v.x; y = v.y;
+    EC_POINT_get_affine_coordinates(eCurve, v, x, y, context);
+
+    byte buf[FIELD_BYTES], md[SHA_DIGEST_LENGTH], t[4];
+    ul32 newHash;
+
+    SHA_CTX hContext;
+
+    // h = First32(SHA-1(pID || v.x || v.y)) >> 4
+    SHA1_Init(&hContext);
+
+    // Chop Product ID into 4 bytes.
+    t[0] = (pID & 0xff);                 // First 8 bits
+    t[1] = (pID & 0xff00) >> 8;          // Second 8 bits
+    t[2] = (pID & 0xff0000) >> 16;       // Third 8 bits
+    t[3] = (pID & 0xff000000) >> 24;     // Fourth 8 bits
+
+    // Hash chunk of data.
+    SHA1_Update(&hContext, t, sizeof(t));
+
+    // Empty buffer, place v.x in little-endian.
+    memset(buf, 0, FIELD_BYTES);
+    BN_bn2bin(x, buf);
+    endian(buf, FIELD_BYTES);
+
+    // Hash chunk of data.
+    SHA1_Update(&hContext, buf, FIELD_BYTES);
+
+    // Empty buffer, place v.y in little-endian.
+    memset(buf, 0, FIELD_BYTES);
+    BN_bn2bin(y, buf);
+    endian(buf, FIELD_BYTES);
+
+    // Hash chunk of data.
+    SHA1_Update(&hContext, buf, FIELD_BYTES);
+
+    // Store the final message from hContext in md.
+    SHA1_Final(md, &hContext);
+
+    // h = First32(SHA-1(pID || v.x || v.y)) >> 4
+    newHash = (md[0] | (md[1] << 8) | (md[2] << 16) | (md[3] << 24)) >> 4;
+    newHash &= 0xfffffff;
+
+    BN_free(e);
+    BN_free(s);
+    BN_free(x);
+    BN_free(y);
+
+    BN_CTX_free(context);
+
+    EC_POINT_free(u);
+    EC_POINT_free(v);
+
+    // If we managed to generate a key with the same hash, the key is correct.
+    return newHash == checkHash;
 }
 
-void generate(uint8_t *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BIGNUM *priv, uint32_t *pid)
-{
-	BN_CTX *ctx = BN_CTX_new();
+/* Generate a valid Product Key. */
+void generateXPKey(char *pKey, EC_GROUP *eCurve, EC_POINT *generator, BIGNUM *order, BIGNUM *privateKey, ul32 *pRaw) {
+    EC_POINT *r = EC_POINT_new(eCurve);
+    BN_CTX *ctx = BN_CTX_new();
 
-	BIGNUM *k = BN_new();
-	BIGNUM *s = BN_new();
-	BIGNUM *x = BN_new();
-	BIGNUM *y = BN_new();
-	EC_POINT *r = EC_POINT_new(ec);
-	uint32_t bkey[4];
+    BIGNUM *c = BN_new();
+    BIGNUM *s = BN_new();
+    BIGNUM *x = BN_new();
+    BIGNUM *y = BN_new();
 
- // Loop in case signaturepart will make cdkey(base-24 "digits") longer than 25 
-	do {
-		BN_pseudo_rand(k, FIELD_BITS, -1, 0);
-		EC_POINT_mul(ec, r, NULL, generator, k, ctx);
-		EC_POINT_get_affine_coordinates_GFp(ec, r, x, y, ctx);
-		
-		SHA_CTX h_ctx;
-		uint8_t t[4], md[20], buf[FIELD_BYTES];
-		uint32_t hash[1];
-		/* h = (fist 32 bits of SHA1(pid || r.x, r.y)) >> 4 */
-		SHA1_Init(&h_ctx);
-		t[0] =  pid[0] & 0xff;
-		t[1] = (pid[0] & 0xff00) >> 8;
-		t[2] = (pid[0] & 0xff0000) >> 16;
-		t[3] = (pid[0] & 0xff000000) >> 24;
-		SHA1_Update(&h_ctx, t, sizeof(t));
-		
-		memset(buf, 0, sizeof(buf));
-		BN_bn2bin(x, buf);
-		endian((uint8_t *)buf, sizeof(buf));
-		SHA1_Update(&h_ctx, buf, sizeof(buf));
-		
-		memset(buf, 0, sizeof(buf));
-		BN_bn2bin(y, buf);
-		endian((uint8_t *)buf, sizeof(buf));
-		SHA1_Update(&h_ctx, buf, sizeof(buf));
-		
-		SHA1_Final(md, &h_ctx);
-		hash[0] = (md[0] | (md[1] << 8) | (md[2] << 16) | (md[3] << 24)) >> 4;
-		hash[0] &= 0xfffffff;
-		
-		/* s = priv*h + k */
-		BN_copy(s, priv);
-		BN_mul_word(s, hash[0]);
-		BN_mod_add(s, s, k, order, ctx);
-		
-		uint32_t sig[2] = {0};
-		BN_bn2bin(s, (uint8_t *)sig);
-		endian((uint8_t *)sig, BN_num_bytes(s));
-		pack(bkey, pid, hash, sig);
-		printf("PID: %.8x\nHash: %.8x\nSig: %.8x %.8x\n", pid[0], hash[0], sig[1], sig[0]);
-	} while (bkey[3] >= 0x40000);
+    ul32 bKey[4]{};
 
-	base24(pkey, bkey);
-	
-	BN_free(k);
-	BN_free(s);
-	BN_free(x);
-	BN_free(y);
-	EC_POINT_free(r);
+    do {
+        ul32 hash = 0, sig[2]{};
 
-	BN_CTX_free(ctx);
-}
+        memset(bKey, 0, 4);
 
-int main()
-{
-    initBink();
+        // 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);
 
-    rand();
-    srand(time(nullptr));
-    rand();
+        // r = generator * c;
+        EC_POINT_mul(eCurve, r, nullptr, generator, c, ctx);
 
- // Init
-	BIGNUM *a, *b, *p, *gx, *gy, *pubx, *puby, *n, *priv;
-	BN_CTX *ctx = BN_CTX_new();
-	
-	// make BigNumbers
-	a = BN_new();
-	b = BN_new();
-	p = BN_new();
-	gx = BN_new();
-	gy = BN_new();
-	pubx = BN_new();
-	puby = BN_new();
-	n = BN_new();
-	priv = BN_new();
+        // x = r.x; y = r.y;
+        EC_POINT_get_affine_coordinates(eCurve, r, x, y, ctx);
 
-    char* BINKID = "2E";
+        SHA_CTX hContext;
+        byte md[SHA_DIGEST_LENGTH]{}, buf[FIELD_BYTES]{}, t[4]{};
 
- // Data from pidgen-Bink-resources
-	/* Elliptic curve parameters: y^2 = x^3 + ax + b mod p */
-	BN_dec2bn(&p,    std::get<0>(BINKData[BINKID].E).c_str());
-    BN_dec2bn(&a,    std::get<1>(BINKData[BINKID].E).c_str());
-    BN_dec2bn(&b,    std::get<2>(BINKData[BINKID].E).c_str());
-	
+        // h = (First-32(SHA1(pRaw, r.x, r.y)) >> 4
+        SHA1_Init(&hContext);
 
-	/* base point (generator) G */
-    BN_dec2bn(&gx,   std::get<0>(BINKData[BINKID].G).c_str());
-    BN_dec2bn(&gy,   std::get<1>(BINKData[BINKID].G).c_str());
+        // Chop Raw Product Key into 4 bytes.
+        t[0] = (*pRaw & 0xff);
+        t[1] = (*pRaw & 0xff00) >> 8;
+        t[2] = (*pRaw & 0xff0000) >> 16;
+        t[3] = (*pRaw & 0xff000000) >> 24;
 
-	/* inverse of public key */
-    BN_dec2bn(&pubx, std::get<0>(BINKData[BINKID].K).c_str());
-    BN_dec2bn(&puby, std::get<1>(BINKData[BINKID].K).c_str());
+        // Hash chunk of data.
+        SHA1_Update(&hContext, t, sizeof(t));
 
- // Computed data
-	/* order of G - computed in 18 hours using a P3-450 */
-    BN_dec2bn(&n,    BINKData[BINKID].n.c_str());
+        // Empty buffer, place r.x in little-endian
+        memset(buf, 0, FIELD_BYTES);
+        BN_bn2bin(x, buf);
+        endian(buf, FIELD_BYTES);
 
-	/* THE private key  - computed in 10 hours using a P3-450 */
-    BN_dec2bn(&priv, BINKData[BINKID].k.c_str());
+        // Hash chunk of data.
+        SHA1_Update(&hContext, buf, FIELD_BYTES);
 
- // Calculation
-	EC_GROUP *ec = EC_GROUP_new_curve_GFp(p, a, b, ctx);
-	EC_POINT *g = EC_POINT_new(ec);
-	EC_POINT_set_affine_coordinates_GFp(ec, g, gx, gy, ctx);
-	EC_POINT *pub = EC_POINT_new(ec);
-	EC_POINT_set_affine_coordinates_GFp(ec, pub, pubx, puby, ctx);
-	
-	uint8_t pkey[26];
-	uint32_t pid[1];
-    pid[0] = 640 * 1000000 ; /* <- change */
-    pid[0] += rand() & 999999;
+        // Empty buffer, place r.y in little-endian.
+        memset(buf, 0, FIELD_BYTES);
+        BN_bn2bin(y, buf);
+        endian(buf, FIELD_BYTES);
 
-    printf("> PID: %d\n", pid[0]);
+        // Hash chunk of data.
+        SHA1_Update(&hContext, buf, FIELD_BYTES);
 
- // generate a key
-    BN_sub(priv, n, priv);
-	generate(pkey, ec, g, n, priv, pid);
-	print_product_key(pkey);
-    printf("\n\n");
+        // Store the final message from hContext in md.
+        SHA1_Final(md, &hContext);
 
- // verify the key
-	verify(ec, g, pub, (char*)pkey);
-	
- // Cleanup
-	BN_CTX_free(ctx);
-	
-	return 0;
-}
+        // h = (First-32(SHA1(pRaw, r.x, r.y)) >> 4
+        hash = (md[0] | (md[1] << 8) | (md[2] << 16) | (md[3] << 24)) >> 4;
+        hash &= 0xfffffff;
+
+        /* s = privateKey * hash + c; */
+        // s = privateKey;
+        BN_copy(s, privateKey);
+
+        // s *= hash;
+        BN_mul_word(s, hash);
+
+        // BN_mod_add() adds a to b % m and places the non-negative result in r.
+        // s = |s + c % order|;
+        BN_mod_add(s, s, c, order, ctx);
+
+        // Convert s from BigNum back to bytecode and reverse the endianness.
+        BN_bn2bin(s, (byte *)sig);
+        endian((byte *)sig, BN_num_bytes(s));
+
+        // Pack product key.
+        packXP(bKey, pRaw, &hash, sig);
+    } while (bKey[3] >= 0x40000);
+    // ↑ ↑ ↑
+    // bKey[3] can't be longer than 18 bits, else the signature part will make
+    // the CD-key longer than 25 characters.
+
+    // Convert the key to Base24.
+    base24(pKey, bKey);
+
+    BN_free(c);
+    BN_free(s);
+    BN_free(x);
+    BN_free(y);
+
+    BN_CTX_free(ctx);
+    EC_POINT_free(r);
+}
\ No newline at end of file