Function generateServerKey

src/server.cpp:201–390

Generates the Windows Server 2003-like Product Key. */

/* Generates the Windows Server 2003-like Product Key. */
VOID generateServerKey(
    EC_GROUP *eCurve,
    EC_POINT *basePoint,
      BIGNUM *genOrder,
      BIGNUM *privateKey,
       DWORD pChannelID,
       DWORD pAuthInfo,
        BOOL pUpgrade,
        CHAR (&pKey)[PK_LENGTH + NULL_TERMINATOR]
) {
    BN_CTX *numContext = BN_CTX_new();

    BIGNUM *c = BN_new(),
           *e = BN_new(),
           *s = BN_new(),
           *x = BN_new(),
           *y = BN_new();

    QWORD pRaw[2]{},
          pSignature = 0;

    // Data segment of the RPK.
    DWORD pData = pChannelID << 1 | pUpgrade;
    BOOL  noSquare;

    do {
        EC_POINT *r = EC_POINT_new(eCurve);

        // 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 = cG
        EC_POINT_mul(eCurve, r, nullptr, basePoint, c, numContext);

        // Acquire its coordinates.
        // x = R.x; y = R.y;
        EC_POINT_get_affine_coordinates(eCurve, r, x, y, numContext);

        BYTE msgDigest[SHA_DIGEST_LENGTH]{},
             msgBuffer[SHA_MSG_LENGTH_2003]{},
             xBin[FIELD_BYTES_2003]{},
             yBin[FIELD_BYTES_2003]{};

        // Convert resulting point coordinates to bytes.
        BN_bn2lebin(x, xBin, FIELD_BYTES_2003);
        BN_bn2lebin(y, yBin, FIELD_BYTES_2003);

        // Assemble the first SHA message.
        msgBuffer[0x00] = 0x79;
        msgBuffer[0x01] = (pData & 0x00FF);
        msgBuffer[0x02] = (pData & 0xFF00) >> 8;

        memcpy((void *)&msgBuffer[3], (void *)xBin, FIELD_BYTES_2003);
        memcpy((void *)&msgBuffer[3 + FIELD_BYTES_2003], (void *)yBin, FIELD_BYTES_2003);

        // pHash = SHA1(79 || Channel ID || R.x || R.y)
        SHA1(msgBuffer, SHA_MSG_LENGTH_2003, msgDigest);