Further readability improvement

This commit is contained in:
Andrew 2023-06-07 02:22:36 +03:00
parent cc3900d4d0
commit 4f7fb772a5
2 changed files with 54 additions and 54 deletions

View File

@ -96,7 +96,7 @@ bool verifyServerKey(
SHA1(msgBuffer, 11, msgDigest);
// Translate the byte digest into a 64-bit integer - this is our computed intermediate signature.
// As the signature is only 62 bits long at most, we have to truncate it by shifting the high DWORD right 2 bits (by spec).
// As the signature is only 62 bits long at most, we have to truncate it by shifting the high DWORD right 2 bits (per spec).
QWORD iSignature = NEXTSNBITS(BYDWORD(&msgDigest[4]), 30, 2) << 32 | BYDWORD(msgDigest);
/*
@ -150,7 +150,7 @@ bool verifyServerKey(
memcpy((void *)&msgBuffer[3], (void *)xBin, FIELD_BYTES_2003);
memcpy((void *)&msgBuffer[3 + FIELD_BYTES_2003], (void *)yBin, FIELD_BYTES_2003);
// newHash = SHA1(79 || Channel ID || p.x || p.y)
// compHash = SHA1(79 || Channel ID || p.x || p.y)
SHA1(msgBuffer, SHA_MSG_LENGTH_2003, msgDigest);
// Translate the byte digest into a 32-bit integer - this is our computed hash.
@ -182,30 +182,30 @@ void generateServerKey(
) {
BN_CTX *numContext = BN_CTX_new();
BIGNUM *c = BN_new();
BIGNUM *s = BN_new();
BIGNUM *x = BN_new();
BIGNUM *y = BN_new();
BIGNUM *e = BN_new();
BIGNUM *c = BN_new(),
*e = BN_new(),
*s = BN_new(),
*x = BN_new(),
*y = BN_new();
QWORD pRaw[2]{},
pSignature = 0;
QWORD pRaw[2]{};
BOOL wrong = false;
QWORD pSignature = 0;
do {
EC_POINT *r = EC_POINT_new(eCurve);
wrong = false;
QWORD sig = 0;
// Generate a random number c consisting of 512 bits without any constraints.
BN_rand(c, FIELD_BITS_2003, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY);
// r = basePoint * c
// R = cG
EC_POINT_mul(eCurve, r, nullptr, basePoint, c, numContext);
// x = r.x; y = r.y;
// Acquire its coordinates.
// x = R.x; y = R.y;
EC_POINT_get_affine_coordinates(eCurve, r, x, y, numContext);
BYTE msgDigest[SHA_DIGEST_LENGTH]{},
@ -217,8 +217,7 @@ void generateServerKey(
BN_bn2lebin(x, xBin, FIELD_BYTES_2003);
BN_bn2lebin(y, yBin, FIELD_BYTES_2003);
// Assemble the SHA message.
// Hash = SHA-1(79 || OS Family || r.x || r.y)
// Assemble the first SHA message.
msgBuffer[0x00] = 0x79;
msgBuffer[0x01] = (pChannelID & 0x00FF);
msgBuffer[0x02] = (pChannelID & 0xFF00) >> 8;
@ -226,30 +225,34 @@ void generateServerKey(
memcpy((void *)&msgBuffer[3], (void *)xBin, FIELD_BYTES_2003);
memcpy((void *)&msgBuffer[3 + FIELD_BYTES_2003], (void *)yBin, FIELD_BYTES_2003);
// Retrieve the message digest.
// pHash = SHA1(79 || Channel ID || R.x || R.y)
SHA1(msgBuffer, SHA_MSG_LENGTH_2003, msgDigest);
DWORD hash = BYDWORD(msgDigest) & BITMASK(31);
// Translate the byte digest into a 32-bit integer - this is our computed hash.
// Truncate the hash to 31 bits.
DWORD pHash = BYDWORD(msgDigest) & BITMASK(31);
// H = SHA-1(5D || OS Family || Hash || Prefix || 00 00)
// Assemble the second SHA message.
msgBuffer[0x00] = 0x5D;
msgBuffer[0x01] = (pChannelID & 0x00FF);
msgBuffer[0x02] = (pChannelID & 0xFF00) >> 8;
msgBuffer[0x03] = (hash & 0x000000FF);
msgBuffer[0x04] = (hash & 0x0000FF00) >> 8;
msgBuffer[0x05] = (hash & 0x00FF0000) >> 16;
msgBuffer[0x06] = (hash & 0xFF000000) >> 24;
msgBuffer[0x03] = (pHash & 0x000000FF);
msgBuffer[0x04] = (pHash & 0x0000FF00) >> 8;
msgBuffer[0x05] = (pHash & 0x00FF0000) >> 16;
msgBuffer[0x06] = (pHash & 0xFF000000) >> 24;
msgBuffer[0x07] = (pAuthInfo & 0x00FF);
msgBuffer[0x08] = (pAuthInfo & 0xFF00) >> 8;
msgBuffer[0x09] = 0x00;
msgBuffer[0x0A] = 0x00;
// newSignature = SHA1(5D || Channel ID || Hash || AuthInfo || 00 00)
SHA1(msgBuffer, 11, msgDigest);
// First word.
sig = NEXTSNBITS(BYDWORD(&msgDigest[4]), 30, 2) << 32 | BYDWORD(msgDigest);
// Translate the byte digest into a 64-bit integer - this is our computed intermediate signature.
// As the signature is only 62 bits long at most, we have to truncate it by shifting the high DWORD right 2 bits (per spec).
QWORD iSignature = NEXTSNBITS(BYDWORD(&msgDigest[4]), 30, 2) << 32 | BYDWORD(msgDigest);
BN_lebin2bn((BYTE *)&sig, sizeof(sig), e);
BN_lebin2bn((BYTE *)&iSignature, sizeof(iSignature), e);
/*
* Signature * (Signature * G + H * K) = rG (mod p)
@ -274,62 +277,59 @@ void generateServerKey(
* s = ( ( -e * privateKey +- sqrt( (e * privateKey)^2 + 4c ) ) / 2 ) % genOrder
*/
// e = (e * privateKey) % genOrder
// e = ek (mod n)
BN_mod_mul(e, e, privateKey, genOrder, numContext);
// s = e
BN_copy(s, e);
// s = (s % genOrder)^2
// s = (s (mod n))^2
BN_mod_sqr(s, s, genOrder, numContext);
// c <<= 2 (c = 4c)
// c <<= 2 (c *= 4)
BN_lshift(c, c, 2);
// s = s + c
// s += c
BN_add(s, s, c);
// s^2 = s % genOrder (genOrder must be prime)
// Around half of numbers modulo a prime are not squares -> BN_sqrt_mod fails about half of the times,
// hence if BN_sqrt_mod returns NULL, we need to restart with a different seed.
// s = sqrt(s (mod n))
if (BN_mod_sqrt(s, s, genOrder, numContext) == nullptr) wrong = true;
// s = s - e
// s = s (mod n) - e
BN_mod_sub(s, s, e, genOrder, numContext);
// if s is odd, s = s + genOrder
if (BN_is_odd(s)) {
// If s is odd, add order to it.
// s += n
if (BN_is_odd(s))
BN_add(s, s, genOrder);
}
// s >>= 1 (s = s / 2)
// s >>= 1 (s /= 2)
BN_rshift1(s, s);
// Convert s from BigNum back to bytecode and reverse the endianness.
// Translate resulting scalar into a 64-bit integer (the byte order is little-endian).
BN_bn2lebinpad(s, (BYTE *)&pSignature, BN_num_bytes(s));
// Pack product key.
packServer(pRaw, pChannelID, hash, pSignature, pAuthInfo);
packServer(pRaw, pChannelID, pHash, pSignature, pAuthInfo);
if (options.verbose) {
fmt::print("Generation results:\n");
fmt::print(" Serial: 0x{:08x}\n", pChannelID);
fmt::print(" Hash: 0x{:08x}\n", hash);
fmt::print(" Hash: 0x{:08x}\n", pHash);
fmt::print(" Signature: 0x{:08x}\n", pSignature);
fmt::print(" AuthInfo: 0x{:08x}\n", pAuthInfo);
fmt::print("\n");
}
EC_POINT_free(r);
} while (pSignature > BITMASK(62) || wrong);
// ↑ ↑ ↑
// The signature can't be longer than 62 bits, else it will
// overlap with the AuthInfo segment next to it.
DWORD chkChannelID, chkHash, chkAuthInfo;
QWORD chkSignature;
unpackServer(pRaw, chkChannelID, chkHash, chkSignature, chkAuthInfo);
if (chkHash != hash || chkSignature != pSignature) {
wrong = true;
}
} while ((HIBYTES(pSignature, sizeof(DWORD)) >= 0x40000000) || wrong);
// Convert bytecode to Base24 CD-key.
base24(pKey, (BYTE *)pRaw);
BN_free(c);

View File

@ -111,7 +111,7 @@ bool verifyXPKey(
memcpy((void *)&msgBuffer[4], (void *)xBin, FIELD_BYTES);
memcpy((void *)&msgBuffer[4 + FIELD_BYTES], (void *)yBin, FIELD_BYTES);
// Retrieve the message digest.
// compHash = SHA1(pSerial || P.x || P.y)
SHA1(msgBuffer, SHA_MSG_LENGTH_XP, msgDigest);
// Translate the byte digest into a 32-bit integer - this is our computed hash.
@ -143,10 +143,10 @@ void generateXPKey(
) {
BN_CTX *numContext = BN_CTX_new();
BIGNUM *c = BN_new();
BIGNUM *s = BN_new();
BIGNUM *x = BN_new();
BIGNUM *y = BN_new();
BIGNUM *c = BN_new(),
*s = BN_new(),
*x = BN_new(),
*y = BN_new();
QWORD pRaw[2]{};
@ -181,7 +181,7 @@ void generateXPKey(
memcpy((void *)&msgBuffer[4], (void *)xBin, FIELD_BYTES);
memcpy((void *)&msgBuffer[4 + FIELD_BYTES], (void *)yBin, FIELD_BYTES);
// Retrieve the message digest.
// pHash = SHA1(pSerial || R.x || R.y)
SHA1(msgBuffer, SHA_MSG_LENGTH_XP, msgDigest);
// Translate the byte digest into a 32-bit integer - this is our computed pHash.