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source/patch/de/maxhenkel/voicechat/voice/common/Secret.java

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+package de.maxhenkel.voicechat.voice.common;
+
+import io.netty.buffer.ByteBuf;
+import java.security.InvalidAlgorithmParameterException;
+import java.security.InvalidKeyException;
+import java.security.Key;
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+import java.util.Arrays;
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.spec.GCMParameterSpec;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+
+public class Secret {
+    public static final int SECRET_SIZE_BYTES = 16;
+    public static final int IV_SIZE_BYTES = 12;
+    public static final int TAG_LEN_BITS = 128;
+    public static final String CIPHER = "AES/GCM/NoPadding";
+    private static final SecureRandom RANDOM = new SecureRandom();
+    private final byte[] secret;
+    private final SecretKeySpec keySpec;
+    private volatile boolean legacyProtocol;
+
+    protected Secret(byte[] secret) {
+        if (secret == null || secret.length != SECRET_SIZE_BYTES) {
+            throw new IllegalArgumentException("Voice chat secret must contain exactly 16 bytes");
+        }
+        this.secret = secret.clone();
+        this.keySpec = new SecretKeySpec(this.secret, "AES");
+    }
+
+    public static Secret generateNewRandomSecret() {
+        byte[] secret = new byte[SECRET_SIZE_BYTES];
+        RANDOM.nextBytes(secret);
+        return new Secret(secret);
+    }
+
+    public static Secret fromBytes(byte[] secret) {
+        return new Secret(secret);
+    }
+
+    public static Secret fromBytes(ByteBuf buf) {
+        byte[] secretBytes = new byte[SECRET_SIZE_BYTES];
+        buf.readBytes(secretBytes);
+        return Secret.fromBytes(secretBytes);
+    }
+
+    public void toBytes(ByteBuf buf) {
+        buf.writeBytes(this.secret);
+    }
+
+    public byte[] getSecret() {
+        return this.secret.clone();
+    }
+
+    public SecretKeySpec getKeySpec() {
+        return this.keySpec;
+    }
+
+    public void setLegacyProtocol(boolean legacyProtocol) {
+        this.legacyProtocol = legacyProtocol;
+    }
+
+    public boolean isLegacyProtocol() {
+        return this.legacyProtocol;
+    }
+
+    public static byte[] generateIV() {
+        byte[] iv = new byte[IV_SIZE_BYTES];
+        RANDOM.nextBytes(iv);
+        return iv;
+    }
+
+    private static byte[] generateLegacyIV() {
+        byte[] iv = new byte[16];
+        RANDOM.nextBytes(iv);
+        return iv;
+    }
+
+    public byte[] encrypt(byte[] data) throws NoSuchPaddingException, NoSuchAlgorithmException,
+            InvalidAlgorithmParameterException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
+        if (this.legacyProtocol) {
+            byte[] iv = Secret.generateLegacyIV();
+            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+            cipher.init(Cipher.ENCRYPT_MODE, (Key) this.keySpec, new IvParameterSpec(iv));
+            byte[] encrypted = cipher.doFinal(data);
+            byte[] payload = new byte[iv.length + encrypted.length];
+            System.arraycopy(iv, 0, payload, 0, iv.length);
+            System.arraycopy(encrypted, 0, payload, iv.length, encrypted.length);
+            return payload;
+        }
+        byte[] iv = Secret.generateIV();
+        Cipher cipher = Cipher.getInstance(CIPHER);
+        cipher.init(Cipher.ENCRYPT_MODE, (Key) this.keySpec, new GCMParameterSpec(TAG_LEN_BITS, iv));
+        byte[] encrypted = cipher.doFinal(data);
+        byte[] payload = new byte[iv.length + encrypted.length];
+        System.arraycopy(iv, 0, payload, 0, iv.length);
+        System.arraycopy(encrypted, 0, payload, iv.length, encrypted.length);
+        return payload;
+    }
+
+    public byte[] decrypt(byte[] payload) throws NoSuchPaddingException, NoSuchAlgorithmException,
+            InvalidAlgorithmParameterException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
+        if (this.legacyProtocol) {
+            if (payload.length < 32 || (payload.length - 16) % 16 != 0) {
+                throw new IllegalBlockSizeException("Invalid legacy AES-CBC packet size");
+            }
+            byte[] iv = Arrays.copyOfRange(payload, 0, 16);
+            byte[] encrypted = Arrays.copyOfRange(payload, 16, payload.length);
+            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+            cipher.init(Cipher.DECRYPT_MODE, (Key) this.keySpec, new IvParameterSpec(iv));
+            return cipher.doFinal(encrypted);
+        }
+        if (payload.length < IV_SIZE_BYTES + 16) {
+            throw new IllegalBlockSizeException("Invalid AES-GCM packet size");
+        }
+        byte[] iv = Arrays.copyOfRange(payload, 0, IV_SIZE_BYTES);
+        byte[] encrypted = Arrays.copyOfRange(payload, IV_SIZE_BYTES, payload.length);
+        Cipher cipher = Cipher.getInstance(CIPHER);
+        cipher.init(Cipher.DECRYPT_MODE, (Key) this.keySpec, new GCMParameterSpec(TAG_LEN_BITS, iv));
+        return cipher.doFinal(encrypted);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        return o instanceof Secret && Arrays.equals(this.secret, ((Secret) o).secret);
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(this.secret);
+    }
+}