package emu.grasscutter.utils; import emu.grasscutter.Grasscutter; import emu.grasscutter.server.http.objects.QueryCurRegionRspJson; import java.io.ByteArrayOutputStream; import java.nio.file.Path; import java.security.KeyFactory; import java.security.PrivateKey; import java.security.PublicKey; import java.security.SecureRandom; import java.security.Signature; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import java.util.Arrays; import java.util.HashMap; import java.util.Map; import java.util.regex.Pattern; import javax.crypto.Cipher; public final class Crypto { private static final SecureRandom secureRandom = new SecureRandom(); public static byte[] DISPATCH_KEY; public static byte[] DISPATCH_SEED; public static byte[] ENCRYPT_KEY; public static long ENCRYPT_SEED = Long.parseUnsignedLong("11468049314633205968"); public static byte[] ENCRYPT_SEED_BUFFER = new byte[0]; public static PrivateKey CUR_SIGNING_KEY; public static Map EncryptionKeys = new HashMap<>(); public static void loadKeys() { DISPATCH_KEY = FileUtils.readResource("/keys/dispatchKey.bin"); DISPATCH_SEED = FileUtils.readResource("/keys/dispatchSeed.bin"); ENCRYPT_KEY = FileUtils.readResource("/keys/secretKey.bin"); ENCRYPT_SEED_BUFFER = FileUtils.readResource("/keys/secretKeyBuffer.bin"); try { CUR_SIGNING_KEY = KeyFactory.getInstance("RSA") .generatePrivate( new PKCS8EncodedKeySpec(FileUtils.readResource("/keys/SigningKey.der"))); Pattern pattern = Pattern.compile("([0-9]*)_Pub\\.der"); for (Path path : FileUtils.getPathsFromResource("/keys/game_keys")) { if (path.toString().endsWith("_Pub.der")) { var m = pattern.matcher(path.getFileName().toString()); if (m.matches()) { var key = KeyFactory.getInstance("RSA") .generatePublic(new X509EncodedKeySpec(FileUtils.read(path))); EncryptionKeys.put(Integer.valueOf(m.group(1)), key); } } } } catch (Exception e) { Grasscutter.getLogger().error("An error occurred while loading keys.", e); } } public static void xor(byte[] packet, byte[] key) { try { for (int i = 0; i < packet.length; i++) { packet[i] ^= key[i % key.length]; } } catch (Exception e) { Grasscutter.getLogger().error("Crypto error.", e); } } public static byte[] createSessionKey(int length) { byte[] bytes = new byte[length]; secureRandom.nextBytes(bytes); return bytes; } public static QueryCurRegionRspJson encryptAndSignRegionData(byte[] regionInfo, String key_id) throws Exception { if (key_id == null) { throw new Exception("Key ID was not set"); } Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); cipher.init(Cipher.ENCRYPT_MODE, EncryptionKeys.get(Integer.valueOf(key_id))); // Encrypt regionInfo in chunks ByteArrayOutputStream encryptedRegionInfoStream = new ByteArrayOutputStream(); // Thank you so much GH Copilot int chunkSize = 256 - 11; int regionInfoLength = regionInfo.length; int numChunks = (int) Math.ceil(regionInfoLength / (double) chunkSize); for (int i = 0; i < numChunks; i++) { byte[] chunk = Arrays.copyOfRange( regionInfo, i * chunkSize, Math.min((i + 1) * chunkSize, regionInfoLength)); byte[] encryptedChunk = cipher.doFinal(chunk); encryptedRegionInfoStream.write(encryptedChunk); } Signature privateSignature = Signature.getInstance("SHA256withRSA"); privateSignature.initSign(CUR_SIGNING_KEY); privateSignature.update(regionInfo); var rsp = new QueryCurRegionRspJson(); rsp.content = Utils.base64Encode(encryptedRegionInfoStream.toByteArray()); rsp.sign = Utils.base64Encode(privateSignature.sign()); return rsp; } }