diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..7f6b7e2
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,15 @@
+CPPFLAGS := $(INC_FLAGS) -Bstatic
+LDFLAGS := -lssl -lcrypto -ldl -pthread
+
+.SILENT: all xpkey srv2003key clean
+
+all: xpkey srv2003key
+
+xpkey:
+	$(CXX) $(CPPFLAGS) main.cpp -o $@ $(LDFLAGS)
+
+srv2003key:
+	$(CXX) $(CPPFLAGS) Srv2003KGmain.cpp -o $@ $(LDFLAGS)
+
+clean:
+	rm -f xpkey srv2003key
\ No newline at end of file
diff --git a/README.md b/README.md
index 9168385..207a187 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@
 
 * **How does it work?**
 
- This program is based on [this paper](https://www.licenturion.com/xp/fully-licensed-wpa.txt) Basically,
+ This program is based on [this paper](fully-licensed-wpa.txt) Basically,
  it uses a cracked private key from Microsoft to sign some stuff encoded in the 25-digit product key. It also does this process in reverse to check for the validation of the keys.
 
 * **How do I use it?**
diff --git a/Srv2003KGmain.cpp b/Srv2003KGmain.cpp
index 48b10c9..5527a88 100644
--- a/Srv2003KGmain.cpp
+++ b/Srv2003KGmain.cpp
@@ -6,15 +6,12 @@
 #include <openssl/rand.h>
 #include <assert.h>
 
-typedef unsigned char U8;
-typedef unsigned long U32;
-
-U8 cset[] = "BCDFGHJKMPQRTVWXY2346789";
+uint8_t cset[] = "BCDFGHJKMPQRTVWXY2346789";
 
 #define FIELD_BITS_2003 512
 #define FIELD_BYTES_2003 64
 
-void unpack2003(U32 *osfamily, U32 *hash, U32 *sig, U32 *prefix, U32 *raw)
+void unpack2003(uint32_t *osfamily, uint32_t *hash, uint32_t *sig, uint32_t *prefix, uint32_t *raw)
 {
 	osfamily[0] = raw[0] & 0x7ff;
 	hash[0] = ((raw[0] >> 11) | (raw[1] << 21)) & 0x7fffffff;
@@ -23,7 +20,7 @@ void unpack2003(U32 *osfamily, U32 *hash, U32 *sig, U32 *prefix, U32 *raw)
 	prefix[0] = (raw[3] >> 8) & 0x3ff;
 }
 
-void pack2003(U32 *raw, U32 *osfamily, U32 *hash, U32 *sig, U32 *prefix)
+void pack2003(uint32_t *raw, uint32_t *osfamily, uint32_t *hash, uint32_t *sig, uint32_t *prefix)
 {
 	raw[0] = osfamily[0] | (hash[0] << 11);
 	raw[1] = (hash[0] >> 21) | (sig[0] << 10);
@@ -31,18 +28,18 @@ void pack2003(U32 *raw, U32 *osfamily, U32 *hash, U32 *sig, U32 *prefix)
 	raw[3] = (sig[1] >> 22) | (prefix[0] << 8);
 }
 
-static void endian(U8 *x, int n)
+static void endian(uint8_t *x, int n)
 {
 	int i;
 	for (i = 0; i < n/2; i++) {
-		U8 t;
+		uint8_t t;
 		t = x[i];
 		x[i] = x[n-i-1];
 		x[n-i-1] = t;
 	}
 }
 
-void unbase24(U32 *x, U8 *c)
+void unbase24(uint32_t *x, uint8_t *c)
 {
 	memset(x, 0, 16);
 	int i, n;
@@ -56,15 +53,15 @@ void unbase24(U32 *x, U8 *c)
 		BN_add_word(y, c[i]);
 	}
 	n = BN_num_bytes(y);
-	BN_bn2bin(y, (U8 *)x);
+	BN_bn2bin(y, (uint8_t *)x);
 	BN_free(y);
 	
-	endian((U8 *)x, n);
+	endian((uint8_t *)x, n);
 }
 
-void base24(U8 *c, U32 *x)
+void base24(uint8_t *c, uint32_t *x)
 {
-	U8 y[16];
+	uint8_t y[16];
 	int i;
 	
 	BIGNUM *z;
@@ -75,16 +72,16 @@ void base24(U8 *c, U32 *x)
 	
 	c[25] = 0;
 	for (i = 24; i >= 0; i--) {
-		U8 t = BN_div_word(z, 24);
+		uint8_t t = BN_div_word(z, 24);
 		c[i] = cset[t];
 	}
 	BN_free(z);
 }
 
-void print_product_key(U8 *pk)
+void print_product_key(uint8_t *pk)
 {
 	int i;
-	assert(strlen(pk) == 25);
+	assert(strlen((const char *)pk) == 25);
 	for (i = 0; i < 25; i++) {
 		putchar(pk[i]);
 		if (i != 24 && i % 5 == 4) putchar('-');
@@ -93,7 +90,7 @@ void print_product_key(U8 *pk)
 
 void verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cdkey)
 {
-	U8 key[25];
+	uint8_t key[25];
 	int i, j, k;
 	
 	BN_CTX *ctx = BN_CTX_new();
@@ -109,16 +106,16 @@ void verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *c
 		if (k >= 25) break;
 	}
 	
-	U32 bkey[4] = {0};
-	U32 osfamily[1], hash[1], sig[2], prefix[1];
+	uint32_t bkey[4] = {0};
+	uint32_t 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]);
 	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]);
 	
-	U8 buf[FIELD_BYTES_2003], md[20];
-	U32 h1[2];
+	uint8_t buf[FIELD_BYTES_2003], md[20];
+	uint32_t h1[2];
 	SHA_CTX h_ctx;
 	
 	/* h1 = SHA-1(5D || OS Family || Hash || Prefix || 00 00) */
@@ -143,10 +140,10 @@ void verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *c
 	BIGNUM *s, *h, *x, *y;
 	x = BN_new();
 	y = BN_new();
-	endian((U8 *)sig, 8);
-	endian((U8 *)h1, 8);
-	s = BN_bin2bn((U8 *)sig, 8, NULL);
-	h = BN_bin2bn((U8 *)h1, 8, NULL);
+	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);
 
 	EC_POINT *r = EC_POINT_new(ec);
 	EC_POINT *t = EC_POINT_new(ec);
@@ -157,7 +154,7 @@ void verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *c
 	EC_POINT_mul(ec, r, NULL, r, s, ctx);
 	EC_POINT_get_affine_coordinates_GFp(ec, r, x, y, ctx);
 	
-	U32 h2[1];
+	uint32_t h2[1];
 	/* h2 = SHA-1(79 || OS Family || r.x || r.y) */
 	SHA1_Init(&h_ctx);
 	buf[0] = 0x79;
@@ -167,12 +164,12 @@ void verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *c
 	
 	memset(buf, 0, FIELD_BYTES_2003);
 	BN_bn2bin(x, buf);
-	endian((U8 *)buf, FIELD_BYTES_2003);
+	endian((uint8_t *)buf, FIELD_BYTES_2003);
 	SHA1_Update(&h_ctx, buf, FIELD_BYTES_2003);
 	
 	memset(buf, 0, FIELD_BYTES_2003);
 	BN_bn2bin(y, buf);
-	endian((U8 *)buf, FIELD_BYTES_2003);
+	endian((uint8_t *)buf, FIELD_BYTES_2003);
 	SHA1_Update(&h_ctx, buf, FIELD_BYTES_2003);
 	
 	SHA1_Final(md, &h_ctx);
@@ -191,7 +188,7 @@ void verify2003(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *c
 	BN_CTX_free(ctx);
 }
 
-void generate2003(U8 *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BIGNUM *priv, U32 *osfamily, U32 *prefix)
+void generate2003(uint8_t *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BIGNUM *priv, uint32_t *osfamily, uint32_t *prefix)
 {
 	BN_CTX *ctx = BN_CTX_new();
 
@@ -202,10 +199,10 @@ void generate2003(U8 *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BI
 	BIGNUM *b = BN_new();
 	EC_POINT *r = EC_POINT_new(ec);
 
-	U32 bkey[4];
-	U8 buf[FIELD_BYTES_2003], md[20];
-	U32 h1[2];
-	U32 hash[1], sig[2];
+	uint32_t bkey[4];
+	uint8_t buf[FIELD_BYTES_2003], md[20];
+	uint32_t h1[2];
+	uint32_t hash[1], sig[2];
 	
 	SHA_CTX h_ctx;
 	
@@ -224,12 +221,12 @@ void generate2003(U8 *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BI
 		
 		memset(buf, 0, FIELD_BYTES_2003);
 		BN_bn2bin(x, buf);
-		endian((U8 *)buf, FIELD_BYTES_2003);
+		endian((uint8_t *)buf, FIELD_BYTES_2003);
 		SHA1_Update(&h_ctx, buf, FIELD_BYTES_2003);
 		
 		memset(buf, 0, FIELD_BYTES_2003);
 		BN_bn2bin(y, buf);
-		endian((U8 *)buf, FIELD_BYTES_2003);
+		endian((uint8_t *)buf, FIELD_BYTES_2003);
 		SHA1_Update(&h_ctx, buf, FIELD_BYTES_2003);
 		
 		SHA1_Final(md, &h_ctx);
@@ -255,8 +252,8 @@ void generate2003(U8 *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BI
 		printf("h1: %.8x %.8x\n", h1[1], h1[0]);
 	
 		/* s = ( -h1*priv + sqrt( (h1*priv)^2 + 4k ) ) / 2 */
-		endian((U8 *)h1, 8);
-		BN_bin2bn((U8 *)h1, 8, b);
+		endian((uint8_t *)h1, 8);
+		BN_bin2bn((uint8_t *)h1, 8, b);
 		BN_mod_mul(b, b, priv, order, ctx);
 		BN_copy(s, b);
 		BN_mod_sqr(s, s, order, ctx);
@@ -269,8 +266,8 @@ void generate2003(U8 *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BI
 		}
 		BN_rshift1(s, s);
 		sig[0] = sig[1] = 0;
-		BN_bn2bin(s, (U8 *)sig);
-		endian((U8 *)sig, BN_num_bytes(s));
+		BN_bn2bin(s, (uint8_t *)sig);
+		endian((uint8_t *)sig, BN_num_bytes(s));
 		if (sig[1] < 0x40000000) break;
 	}
 	pack2003(bkey, osfamily, hash, sig, prefix);
@@ -325,15 +322,15 @@ int main()
 	assert(EC_POINT_is_on_curve(ec, g, ctx) == 1);
 	assert(EC_POINT_is_on_curve(ec, pub, ctx) == 1);
 	
-	U8 pkey[25];
-	U32 osfamily[1], prefix[1];
+	uint8_t pkey[25];
+	uint32_t osfamily[1], prefix[1];
 	
 	osfamily[0] = 1280;
-	RAND_pseudo_bytes((U8 *)prefix, 4);
+	RAND_pseudo_bytes((uint8_t *)prefix, 4);
 	prefix[0] &= 0x3ff;
 	generate2003(pkey, ec, g, n, priv, osfamily, prefix);
 	print_product_key(pkey); printf("\n\n");
-	verify2003(ec, g, pub, pkey);
+	verify2003(ec, g, pub, (char*)pkey);
 
 	BN_CTX_free(ctx);
 	
diff --git a/fully-licensed-wpa.txt b/fully-licensed-wpa.txt
new file mode 100644
index 0000000..0de4d0d
--- /dev/null
+++ b/fully-licensed-wpa.txt
@@ -0,0 +1,607 @@
+
+                  Inside Windows Product Activation
+
+                        A Fully Licensed Paper
+
+                              July 2001
+
+   Fully Licensed GmbH, Rudower Chaussee 29, 12489 Berlin, Germany
+
+                      http://www.licenturion.com
+
+
+>> INTRODUCTION
+
+The current public discussion of Windows Product Activation (WPA) is
+characterized by uncertainty and speculation. In this paper we supply
+the technical details of WPA - as implemented in Windows XP - that
+Microsoft should have published long ago.
+
+While we strongly believe that every software vendor has the right to
+enforce the licensing terms governing the use of a piece of licensed
+software by technical means, we also do believe that each individual
+has the right to detailed knowledge about the full implications of the
+employed means and possible limitations imposed by it on software
+usage.
+
+In this paper we answer what we think are currently the two most
+important open questions related to Windows Product Activation.
+
+  * Exactly what information is transmitted during activation?
+
+  * How do hardware modifications affect an already activated
+    installation of Windows XP?
+
+Our answers to these questions are based on Windows XP Release
+Candidate 1 (build 2505). Later builds as well as the final version of
+Windows XP might differ from build 2505, e.g. in the employed
+cryptographic keys or the layout of some of the data
+structures.
+
+However, beyond such minor modifications we expect Microsoft to cling
+to the general architecture of their activation mechanism. Thus, we
+are convinced that the answers provided by this paper will still be
+useful when the final version of Windows XP ships.
+
+This paper supplies in-depth technical information about the inner
+workings of WPA. Still, the discussion is a little vague at some
+points in order not to facilitate the task of an attacker attempting
+to circumvent the license enforcement supplied by the activation
+mechanism.
+
+XPDec, a command line utility suitable for verifying the presented
+information, can be obtained from http://www.licenturion.com/xp/. It
+implements the algorithms presented in this paper. Reading its source
+code, which is available from the same location, is highly
+recommended.
+
+We have removed an important cryptographic key from the XPDec source
+code. Recompiling the source code will thus fail to produce a working
+executable. The XPDec executable on our website, however, contains
+this key and is fully functional.
+
+So, download the source code to learn about the inner workings of WPA,
+but obtain the executable to experiment with your installation of
+Windows XP.
+
+We expect the reader to be familiar with the general procedure of
+Windows Product Activation.
+
+>> INSIDE THE INSTALLATION ID
+
+We focused our research on product activation via telephone. We did
+so, because we expected this variant of activation to be the most
+straight-forward to analyze.
+
+The first step in activating Windows XP via telephone is supplying the
+call-center agent with the Installation ID displayed by msoobe.exe,
+the application that guides a user through the activation process. The
+Installation ID is a number consisting of 50 decimal digits that are
+divided into groups of six digits each, as in
+
+      002666-077894-484890-114573-XXXXXX-XXXXXX-XXXXXX-XXXXXX-XX
+
+In this authentic Installation ID we have substituted digits that we
+prefer not to disclose by 'X' characters.
+
+If msoobe.exe is invoked more than once, it provides a different
+Installation ID each time.
+
+In return, the call-center agent provides a Confirmation ID matching
+the given Installation ID. Entering the Confirmation ID completes the
+activation process.
+
+Since the Installation ID is the only piece of information revealed
+during activation, the above question concerning the information
+transmitted during the activation process is equivalent to the
+question
+
+               'How is the Installation ID generated?'
+
+To find an answer to this question, we trace back each digit of the
+Installation ID to its origins.
+
+>>> Check digits
+
+The rightmost digit in each of the groups is a check digit to guard
+against simple errors such as the call center agent's mistyping of one
+of the digits read to him or her. The value of the check digit is
+calculated by adding the other five digits in the group, adding the
+digits at even positions a second time, and dividing the sum by
+seven. The remainder of the division is the value of the check
+digit. In the above example the check digit for the first group (6) is
+calculated as follows.
+
+         1 | 2 | 3 | 4 | 5  <- position
+        ---+---+---+---+---
+         0 | 0 | 2 | 6 | 6  <- digits
+
+         0 + 0 + 2 + 6 + 6 = 14       (step 1: add all digits)
+             0     + 6     + 14 = 20  (step 2: add even digits again)
+
+     step 3: division
+             20 / 7 = 2, remainder is 20 - (2 * 7) = 6
+
+             => check digit is 6
+
+Adding the even digits twice is probably intended to guard against the
+relatively frequent error of accidentally swapping two digits while
+typing, as in 00626 vs. 00266, which yield different check digits.
+
+>>> Decoding
+
+Removing the check digits results in a 41-digit decimal number. A
+decimal number of this length roughly corresponds to a 136-bit binary
+number. In fact, the 41-digit number is just the decimal encoding of
+such a 136-bit multi-precision integer, which is stored in little
+endian byte order as a byte array. Hence, the above Installation ID
+can also be represented as a sequence of 17 bytes as in
+
+               0xXX 0xXX 0xXX 0xXX 0xXX 0xXX 0xXX 0xXX
+               0x94 0xAA 0x46 0xD6 0x0F 0xBD 0x2C 0xC8
+               0x00
+
+In this representation of the above Installation ID 'X' characters
+again substitute the digits that we prefer not to disclose. The '0x'
+prefix denotes hex notation throughout this paper.
+
+>>> Decryption
+
+When decoding arbitrary Installation IDs it can be noticed that the
+most significant byte always seems to be 0x00 or 0x01, whereas the
+other bytes look random. The reason for this is that the lower 16
+bytes of the Installation ID are encrypted, whereas the most
+significant byte is kept in plaintext.
+
+The cryptographic algorithm employed to encrypt the Installation ID is
+a proprietary four-round Feistel cipher. Since the block of input
+bytes passed to a Feistel cipher is divided into two blocks of equal
+size, this class of ciphers is typically applied to input blocks
+consisting of an even number of bytes - in this case the lower 16 of
+the 17 input bytes. The round function of the cipher is the SHA-1
+message digest algorithm keyed with a four-byte sequence.
+
+Let + denote the concatenation of two byte sequences, ^ the XOR
+operation, L and R the left and right eight-byte input half for one
+round, L' and R' the output halves of said round, and First-8() a
+function that returns the first eight bytes of an SHA-1 message
+digest. Then one round of decryption looks as follows.
+
+          L' = R ^ First-8(SHA-1(L + Key))
+          R' = L
+
+The result of the decryption is 16 bytes of plaintext, which are -
+together with the 17th unencrypted byte - from now on interpreted as
+four double words in little endian byte order followed by a single
+byte as in
+
+                     name | size        | offset
+                     -----+-------------+-------
+                      H1  | double word |      0
+                      H2  | double word |      4
+                      P1  | double word |      8
+                      P2  | double word |     12
+                      P3  | byte        |     16
+
+H1 and H2 specify the hardware configuration that the Installation ID
+is linked to. P1 and P2 as well as the remaining byte P3 contain the
+Product ID associated with the Installation ID.
+
+>>> Product ID
+
+The Product ID consists of five groups of decimal digits, as in
+
+                       AAAAA-BBB-CCCCCCC-DDEEE
+
+If you search your registry for a value named 'ProductID', you will
+discover the ID that applies to your installation. The 'About' window
+of Internet Explorer should also yield your Product ID.
+
+>>>> Decoding
+
+The mapping between the Product ID in decimal representation and its
+binary encoding in the double words P1 and P2 and the byte P3 is
+summarized in the following table.
+
+       digits |  length | encoding
+      --------+---------+---------------------------------------
+        AAAAA | 17 bits | bit  0 to bit 16 of P1
+          BBB | 10 bits | bit 17 to bit 26 of P1
+      CCCCCCC | 28 bits | bit 27 to bit 31 of P1 (lower  5 bits)
+              |         | bit  0 to bit 22 of P2 (upper 23 bits)
+        DDEEE | 17 bits | bit 23 to bit 31 of P2 (lower  9 bits)
+              |         | bit  0 to bit  7 of P3 (upper  8 bits)
+
+The meaning of each of the five groups of digits is documented in the
+next table.
+
+       digits | meaning
+      --------+-------------------------------------------------
+        AAAAA | apparently always 55034 (in Windows XP RC1)
+          BBB | most significant three digits of Raw Product Key
+              | (see below)
+      CCCCCCC | least significant six digits of Raw Product Key
+              | plus check digit (see below)
+           DD | index of the public key used to verify the
+              | Product Key (see below)
+          EEE | random value
+
+As can be seen, the (Raw) Product Key plays an important role in
+generating the Product ID.
+
+>>>> Product Key
+
+The Raw Product Key is buried inside the Product Key that is printed
+on the sticker distributed with each Windows XP CD. It consists of
+five alphanumeric strings separated by '-' characters, where each
+string is composed of five characters, as in
+
+                    FFFFF-GGGGG-HHHHH-JJJJJ-KKKKK
+
+Each character is one of the following 24 letters and digits:
+
+           B C D F G H J K M P Q R T V W X Y 2 3 4 6 7 8 9
+
+Very similar to the decimal encoding of the Installation ID the 25
+characters of the Product Key form a base-24 encoding of the binary
+representation of the Product Key. Decoding the Product Key yields a
+multi-precision integer of roughly 115 bits, which is stored - again
+in little endian byte order - in an array of 15 bytes. Decoding the
+above Product Key results in the following byte sequence.
+
+               0x6F 0xFA 0x95 0x45 0xFC 0x75 0xB5 0x52
+               0xBB 0xEF 0xB1 0x17 0xDA 0xCD 0x00
+
+Of these 15 bytes the least significant four bytes contain the Raw
+Product Key in little endian byte order. The least significant bit is
+removed by shifting this 32-bit value (0x4595FA6F - remember the
+little endian byte order) to the left by one bit position, resulting
+in a Raw Product Key of 0x22CAFD37, or
+
+                              583728439
+
+in decimal notation.
+
+The eleven remaining bytes form a digital signature, allowing
+verification of the authenticity of the Product Key by means of a
+hard-coded public key.
+
+>>>> Product Key -> Product ID
+
+The three most significant digits, i.e. 583, of the Raw Product Key's
+nine-digit decimal representation directly map to the BBB component of
+the Product ID described above.
+
+To obtain the CCCCCCC component, a check digit is appended to the
+remaining six digits 728439. The check digit is chosen such that the
+sum of all digits - including the check digit - is divisible by
+seven. In the given case, the sum of the six digits is
+
+               7 + 2 + 8 + 4 + 3 + 9     = 33
+
+which results in a check digit of 2, since
+
+               7 + 2 + 8 + 4 + 3 + 9 + 2 = 33 + 2 = 35
+
+which is divisible by seven. The CCCCCCC component of the Product ID
+is therefore 7284392.
+
+For verifying a Product Key, more than one public key is available. If
+verification with the first public key fails, the second is tried,
+etc. The DD component of the Product ID specifies which of the public
+keys in this sequence was successfully used to verify the Product Key.
+
+This mechanism might be intended to support several different parties
+generating valid Product Keys with different individual private keys.
+
+However, the different private keys might also represent different
+versions of a product. A Product Key for the 'professional' release
+could then be signed with a different key than a Product Key for the
+'server' release. The DD component would then represent the product
+version.
+
+Finally, a valid Product ID derived from our example Product Key might
+be
+
+                       55034-583-7284392-00123
+
+which indicates that the first public key (DD = index = 0) matched and
+123 was chosen as the random number EEE.
+
+The randomly selected EEE component is the reason for msoobe.exe
+presenting a different Installation ID at each invocation. Because of
+the applied encryption this small change results in a completely
+different Installation ID.
+
+So, the Product ID transmitted during activation will most probably
+differ in the last three digits from your Product ID as displayed by
+Internet Explorer or as stored in the registry.
+
+>>> Hardware Information
+
+As discussed above, the hardware configuration linked to the
+Installation ID is represented by the two double words H1 and H2.
+
+>>>> Bit-fields
+
+For this purpose, the double words are divided into twelve
+bit-fields. The relationship between the computer hardware and the
+bit-fields is given in the following table.
+
+    double word | offset | length | bit-field value based on
+    ------------+--------+--------+----------------------------
+         H1     |      0 |     10 | volume serial number string
+                |        |        | of system volume
+         H1     |     10 |     10 | network adapter MAC address
+                |        |        | string
+         H1     |     20 |      7 | CD-ROM drive hardware
+                |        |        | identification string
+         H1     |     27 |      5 | graphics adapter hardware
+                |        |        | identification string
+         H2     |      0 |      3 | unused, set to 001
+         H2     |      3 |      6 | CPU serial number string
+         H2     |      9 |      7 | harddrive hardware
+                |        |        | identification string
+         H2     |     16 |      5 | SCSI host adapter hardware
+                |        |        | identification string
+         H2     |     21 |      4 | IDE controller hardware
+                |        |        | identification string
+         H2     |     25 |      3 | processor model string
+         H2     |     28 |      3 | RAM size
+         H2     |     31 |      1 | 1 = dockable
+                |        |        | 0 = not dockable
+
+Bit 31 of H2 specifies, whether the bit-fields represent a notebook
+computer that supports a docking station. If docking is possible, the
+activation mechanism will be more tolerant with respect to future
+hardware modifications. Here, the idea is that plugging a notebook
+into its docking station possibly results in changes to its hardware
+configuration, e.g. a SCSI host adapter built into the docking station
+may become available.
+
+Bits 2 through 0 of H2 are unused and always set to 001.
+
+If the hardware component corresponding to one of the remaining ten
+bit-fields is present, the respective bit-field contains a non-zero
+value describing the component. A value of zero marks the hardware
+component as not present.
+
+All hardware components are identified by a hardware identification
+string obtained from the registry. Hashing this string provides the
+value for the corresponding bit-field.
+
+>>>> Hashing
+
+The hash result is obtained by feeding the hardware identification
+string into the MD5 message digest algorithm and picking the number of
+bits required for a bit-field from predetermined locations in the
+resulting message digest. Different predetermined locations are used
+for different bit-fields. In addition, a hash result of zero is
+avoided by calculating
+
+                   Hash = (Hash % BitFieldMax) + 1
+
+where BitFieldMax is the maximal value that may be stored in the
+bit-field in question, e.g. 1023 for a 10-bit bit-field, and 'x % y'
+denotes the remainder of the division of x by y. This results in
+values between 1 and BitFieldMax. The obtained value is then stored in
+the respective bit-field.
+
+>>>> RAM bit-field
+
+The bit-field related to the amount of RAM available to the operating
+system is calculated differently. The seven valid values specify the
+approximate amount of available RAM as documented in the following
+table.
+
+                  value | amount of RAM available
+                  ------+---------------------------
+                      0 | (bit-field unused)
+                      1 | below    32 MB
+                      2 | between  32 MB and   63 MB
+                      3 | between  64 MB and  127 MB
+                      4 | between 128 MB and  255 MB
+                      5 | between 256 MB and  511 MB
+                      6 | between 512 MB and 1023 MB
+                      7 | above              1023 MB
+
+It is important to note that the amount of RAM is retrieved by calling
+the GlobalMemoryStatus() function, which reports a few hundred
+kilobytes less than the amount of RAM physically installed. So, 128 MB
+of RAM would typically be classified as "between 64 MB and 127 MB".
+
+>>>> Real-world example
+
+Let us have a look at a real-world example. On one of our test systems
+the hardware information consists of the following eight bytes.
+
+               0xC5 0x95 0x12 0xAC 0x01 0x6E 0x2C 0x32
+
+Converting the bytes into H1 and H2, we obtain
+
+                 H1 = 0xAC1295C5 and H2 = 0x322C6E01
+
+Splitting H1 and H2 yields the next table in which we give the value
+of each of the bit-fields and the information from which each value is
+derived.
+
+   dw &  |       |
+  offset | value | derived from
+  -------+-------+-----------------------------------------------
+   H1  0 | 0x1C5 | '1234-ABCD'
+   H1 10 | 0x0A5 | '00C0DF089E44'
+   H1 20 |  0x37 | 'SCSI\CDROMPLEXTOR_CD-ROM_PX-32TS__1.01'
+   H1 27 |  0x15 | 'PCI\VEN_102B&DEV_0519&SUBSYS_00000000&REV_01'
+   H2  0 |   0x1 | (unused, always 0x1)
+   H2  3 |  0x00 | (CPU serial number not present)
+   H2  9 |  0x37 | 'SCSI\DISKIBM_____DCAS-34330______S65A'
+   H2 16 |  0x0C | 'PCI\VEN_9004&DEV_7178&SUBSYS_00000000&REV_03'
+   H2 21 |   0x1 | 'PCI\VEN_8086&DEV_7111&SUBSYS_00000000&REV_01'
+   H2 25 |   0x1 | 'GenuineIntel Family 6 Model 3'
+   H2 28 |   0x3 | (system has 128 MB of RAM)
+   H2 31 |   0x0 | (system is not dockable)
+
+>>> Using XPDec
+
+XPDec is a utility to be run from the command prompt. It may be
+invoked with one of four command line options to carry out one of four
+tasks.
+
+>>>> XPDec -i
+
+This option enables you to access the information hidden in an
+Installation ID. It decodes the Installation ID, decrypts it, and
+displays the values of the hardware bit-fields as well as the Product
+ID of your product. Keep in mind that the last three digits of the
+Product ID contained in the Installation ID are randomly selected and
+differ from the Product ID displayed by Internet Explorer.
+
+The only argument needed for the '-i' option is the Installation ID,
+as in
+
+ XPDec -i 002666-077894-484890-114573-XXXXXX-XXXXXX-XXXXXX-XXXXXX-XX
+
+>>>> XPDec -p
+
+To help you trace the origin of your Product ID, this option decodes a
+Product Key and displays the Raw Product Key as it would be used in a
+Product ID.
+
+The only argument needed for the '-p' option is the Product Key, as in
+
+                XPDec -p FFFFF-GGGGG-HHHHH-JJJJJ-KKKKK
+
+Note that this option does not verify the digital signature of the
+Product Key.
+
+>>>> XPDec -v
+
+This option calculates the hash of a given volume serial number. It
+was implemented to illustrate our description of string hashing. First
+use '-i' to display the hardware bit-fields. Then use this option to
+verify our claims concerning the volume serial number hash.
+
+The only argument needed for the '-v' option is the volume serial
+number of your system volume, as in
+
+                          XPDec -v 1234-ABCD
+
+(The volume serial number is part of the 'dir' command's output.)
+
+>>>> XPDec -m
+
+This option calculates the network adapter bit-field value
+corresponding to the given MAC address. Similar to '-v' this option
+was implemented as a proof of concept.
+
+The only argument needed for the '-m' option is the MAC address of
+your network adapter, as in
+
+                      XPDec -m 00-C0-DF-08-9E-44
+
+(Use the 'route print' command to obtain the MAC address of your
+network adapter.)
+
+>> HARDWARE MODIFICATIONS
+
+When looking at the effects of hardware modifications on an already
+activated installation of Windows XP, the file 'wpa.dbl' in the
+'system32' directory plays a central role. It is a simple
+RC4-encrypted database that stores, among other things like expiration
+information and the Confirmation ID of an activated installation,
+
+  a) the bit-field values representing the current hardware
+     configuration,
+
+  and
+
+  b) the bit-field values representing the hardware configuration
+     at the time of product activation.
+
+While a) is automatically updated each time the hardware configuration
+is modified in order to reflect the changes, b) remains fixed. Hence,
+b) can be thought of as a snapshot of the hardware configuration at
+the time of product activation.
+
+This snapshot does not exist in the database before product activation
+and if we compare the size of 'wpa.dbl' before and after activation,
+we will notice an increased file size. This is because the snapshot is
+added to the database.
+
+When judging whether re-activation is necessary, the bit-field values
+of a) are compared to the bit-field values of b), i.e. the current
+hardware configuration is compared to the hardware configuration at
+the time of activation.
+
+>>> Non-dockable computer
+
+Typically all bit-fields with the exception of the unused field and
+the 'dockable' field are compared. If more than three of these ten
+bit-fields have changed in a) since product activation, re-activation
+is required.
+
+This means, for example, that in our above real-world example, we
+could replace the harddrive and the CD-ROM drive and substantially
+upgrade our RAM without having to re-activate our Windows XP
+installation.
+
+However, if we completely re-installed Windows XP, the information in
+b) would be lost and we would have to re-activate our installation,
+even if we had not changed our hardware.
+
+>>> Dockable computer
+
+If bit 31 of H2 indicates that our computer supports a docking
+station, however, only seven of the ten bit-fields mentioned above are
+compared. The bit-fields corresponding to the SCSI host adapter, the
+IDE controller, and the graphics board are omitted. But again, of
+these remaining seven bit-fields, only up to three may change without
+requiring re-activation.
+
+>> CONCLUSIONS
+
+In this paper we have given a technical overview of Windows Product
+Activation as implemented in Windows XP. We have shown what
+information the data transmitted during product activation is derived
+from and how hardware upgrades affect an already activated
+installation.
+
+Looking at the technical details of WPA, we do not think that it is as
+problematic as many people have expected. We think so, because WPA is
+tolerant with respect to hardware modifications. In addition, it is
+likely that more than one hardware component map to a certain value
+for a given bit-field. From the above real-world example we know that
+the PX-32TS maps to the value 0x37 = 55. But there are probably many
+other CD-ROM drives that map to the same value. Hence, it is
+impossible to tell from the bit-field value whether it is a PX-32TS
+that we are using or one of the other drives that map to the same
+value.
+
+In contrast to many critics of Windows Product Activation, we think
+that WPA does not prevent typical hardware modifications and,
+moreover, respects the user's right to privacy.
+
+>> ABOUT THE AUTHORS
+
+Fully Licensed GmbH is a start-up company focusing on novel approaches
+to online software licensing and distribution. Have a look at their
+website at
+
+                      http://www.licenturion.com
+
+for more information.
+
+Their research branch every now and then analyzes licensing solutions
+implemented by other companies.
+
+>> COPYRIGHT
+
+Copyright (C) 2001 Fully Licensed GmbH (www.licenturion.com)
+All rights reserved.
+
+You are free to do whatever you want with this paper. However, you
+have to supply the URL of its online version
+
+                    http://www.licenturion.com/xp/
+
+with any work derived from this paper to give credit to its authors.
diff --git a/main.cpp b/main.cpp
index 8f45a12..bcbe02c 100644
--- a/main.cpp
+++ b/main.cpp
@@ -25,10 +25,10 @@
 
 #define FIELD_BITS 384
 #define FIELD_BYTES 48
-unsigned char cset[] = "BCDFGHJKMPQRTVWXY2346789";
+uint8_t cset[] = "BCDFGHJKMPQRTVWXY2346789";
 
 
-static void unpack(unsigned long *pid, unsigned long *hash, unsigned long *sig, unsigned long *raw)
+static void unpack(uint32_t *pid, uint32_t *hash, uint32_t *sig, uint32_t *raw)
 {
  // pid = Bit 0..30 
 	pid[0] = raw[0] & 0x7fffffff;
@@ -41,7 +41,7 @@ static void unpack(unsigned long *pid, unsigned long *hash, unsigned long *sig,
 	sig[1] = (raw[2] >> 27) | (raw[3] << 5);
 }
 
-static void pack(unsigned long *raw, unsigned long *pid, unsigned long *hash, unsigned long *sig)
+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);
@@ -50,18 +50,18 @@ static void pack(unsigned long *raw, unsigned long *pid, unsigned long *hash, un
 }
 
 // Reverse data
-static void endian(unsigned char *data, int len)
+static void endian(uint8_t *data, int len)
 {
 	int i;
 	for (i = 0; i < len/2; i++) {
-		unsigned char temp;
+		uint8_t temp;
 		temp = data[i];
 		data[i] = data[len-i-1];
 		data[len-i-1] = temp;
 	}
 }
 
-void unbase24(unsigned long *x, unsigned char *c)
+void unbase24(uint32_t *x, uint8_t *c)
 {
 
 	memset(x, 0, 16);
@@ -76,15 +76,15 @@ void unbase24(unsigned long *x, unsigned char *c)
 		BN_add_word(y, c[i]);
 	}
 	n = BN_num_bytes(y);
-	BN_bn2bin(y, (unsigned char *)x);
+	BN_bn2bin(y, (uint8_t *)x);
 	BN_free(y);
 	
-	endian((unsigned char *)x, n);
+	endian((uint8_t *)x, n);
 }
 
-void base24(unsigned char *c, unsigned long *x)
+void base24(uint8_t *c, uint32_t *x)
 {
-	unsigned char y[16];
+	uint8_t y[16];
 	int i;
 	BIGNUM *z;
 
@@ -98,14 +98,14 @@ void base24(unsigned char *c, unsigned long *x)
  // Divide z by 24 and convert remainder with cset to Base24-CDKEY Char
 	c[25] = 0;
 	for (i = 24; i >= 0; i--) {
-		unsigned char t = BN_div_word(z, 24);
+		uint8_t t = BN_div_word(z, 24);
 		c[i] = cset[t];
 	}
 
 	BN_free(z);
 }
 
-void print_product_id(unsigned long *pid)
+void print_product_id(uint32_t *pid)
 {
 	char raw[12];
 	char b[6], c[8];
@@ -134,7 +134,7 @@ void print_product_id(unsigned long *pid)
 	printf("Product ID: 55274-%s-%s-23xxx\n", b, c);
 }
 
-void print_product_key(unsigned char *pk)
+void print_product_key(uint8_t *pk)
 {
 	int i;
 	assert(strlen((const char *)pk) == 25);
@@ -146,7 +146,7 @@ void print_product_key(unsigned char *pk)
 
 void verify(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cdkey)
 {
-	unsigned char key[25];
+	uint8_t key[25];
 	int i, j, k;
 
 	BN_CTX *ctx = BN_CTX_new();
@@ -163,8 +163,8 @@ void verify(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cdkey
 	}
 	
  // Base24_CDKEY -> Bin_CDKEY
-	unsigned long bkey[4] = {0};
-	unsigned long pid[1], hash[1], sig[2];
+	uint32_t bkey[4] = {0};
+	uint32_t pid[1], hash[1], sig[2];
 	unbase24(bkey, key);
  
  // Output Bin_CDKEY
@@ -182,8 +182,8 @@ void verify(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cdkey
 	/* e = hash, s = sig */
 	e = BN_new();
 	BN_set_word(e, hash[0]);
-	endian((unsigned char *)sig, sizeof(sig));
-	s = BN_bin2bn((unsigned char *)sig, sizeof(sig), NULL);
+	endian((uint8_t *)sig, sizeof(sig));
+	s = BN_bin2bn((uint8_t *)sig, sizeof(sig), NULL);
 	
 	BIGNUM *x = BN_new();
 	BIGNUM *y = BN_new();
@@ -196,9 +196,9 @@ void verify(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cdkey
 	EC_POINT_add(ec, v, u, v, ctx);
 	EC_POINT_get_affine_coordinates_GFp(ec, v, x, y, ctx);
 	
-	unsigned char buf[FIELD_BYTES], md[20];
-	unsigned long h;
-	unsigned char t[4];
+	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 */
@@ -211,12 +211,12 @@ void verify(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cdkey
 	
 	memset(buf, 0, sizeof(buf));
 	BN_bn2bin(x, buf);
-	endian((unsigned char *)buf, sizeof(buf));
+	endian((uint8_t *)buf, sizeof(buf));
 	SHA1_Update(&h_ctx, buf, sizeof(buf));
 	
 	memset(buf, 0, sizeof(buf));
 	BN_bn2bin(y, buf);
-	endian((unsigned char *)buf, sizeof(buf));
+	endian((uint8_t *)buf, sizeof(buf));
 	SHA1_Update(&h_ctx, buf, sizeof(buf));
 	
 	SHA1_Final(md, &h_ctx);
@@ -238,7 +238,7 @@ void verify(EC_GROUP *ec, EC_POINT *generator, EC_POINT *public_key, char *cdkey
 	BN_CTX_free(ctx);
 }
 
-void generate(unsigned char *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BIGNUM *priv, unsigned long *pid)
+void generate(uint8_t *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *order, BIGNUM *priv, uint32_t *pid)
 {
 	BN_CTX *ctx = BN_CTX_new();
 
@@ -247,7 +247,7 @@ void generate(unsigned char *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *or
 	BIGNUM *x = BN_new();
 	BIGNUM *y = BN_new();
 	EC_POINT *r = EC_POINT_new(ec);
-	unsigned long bkey[4];
+	uint32_t bkey[4];
 
  // Loop in case signaturepart will make cdkey(base-24 "digits") longer than 25 
 	do {
@@ -256,8 +256,8 @@ void generate(unsigned char *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *or
 		EC_POINT_get_affine_coordinates_GFp(ec, r, x, y, ctx);
 		
 		SHA_CTX h_ctx;
-		unsigned char t[4], md[20], buf[FIELD_BYTES];
-		unsigned long hash[1];
+		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;
@@ -268,12 +268,12 @@ void generate(unsigned char *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *or
 		
 		memset(buf, 0, sizeof(buf));
 		BN_bn2bin(x, buf);
-		endian((unsigned char *)buf, sizeof(buf));
+		endian((uint8_t *)buf, sizeof(buf));
 		SHA1_Update(&h_ctx, buf, sizeof(buf));
 		
 		memset(buf, 0, sizeof(buf));
 		BN_bn2bin(y, buf);
-		endian((unsigned char *)buf, sizeof(buf));
+		endian((uint8_t *)buf, sizeof(buf));
 		SHA1_Update(&h_ctx, buf, sizeof(buf));
 		
 		SHA1_Final(md, &h_ctx);
@@ -285,9 +285,9 @@ void generate(unsigned char *pkey, EC_GROUP *ec, EC_POINT *generator, BIGNUM *or
 		BN_mul_word(s, hash[0]);
 		BN_mod_add(s, s, k, order, ctx);
 		
-		unsigned long sig[2] = {0};
-		BN_bn2bin(s, (unsigned char *)sig);
-		endian((unsigned char *)sig, BN_num_bytes(s));
+		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] >= 0x62a32);
@@ -349,8 +349,8 @@ int main()
 	EC_POINT *pub = EC_POINT_new(ec);
 	EC_POINT_set_affine_coordinates_GFp(ec, pub, pubx, puby, ctx);
 	
-	unsigned char pkey[26];
-	unsigned long pid[1];
+	uint8_t pkey[26];
+	uint32_t pid[1];
 	pid[0] = 640000000 << 1; /* <- change */
 
  // generate a key