diff --git a/generator/src/main/java/io/github/lonamiwebs/overgram/generator/Generator.java b/generator/src/main/java/io/github/lonamiwebs/overgram/generator/Generator.java
index e153015..3ed08f1 100644
--- a/generator/src/main/java/io/github/lonamiwebs/overgram/generator/Generator.java
+++ b/generator/src/main/java/io/github/lonamiwebs/overgram/generator/Generator.java
@@ -180,12 +180,16 @@ public class Generator {
                 writer.write(arg.javaSetCheck());
                 writer.write(") { ");
             }
-            if (!arg.flags) {
-                writer.write("writer.write(" + VARIABLE_SUFFIX + i + ");");
-            } else {
+            if (arg.flags) {
                 writer.write("writer.write(");
                 writer.write(arg.name);
                 writer.write(");");
+            } else {
+                writer.write("writer.write(" + VARIABLE_SUFFIX + i);
+                if (arg.bigIntSize() != 0) {
+                    writer.write(", " + arg.bigIntSize());
+                }
+                writer.write(");");
             }
             if (arg.flag != null) {
                 writer.write(" }\n");
diff --git a/generator/src/main/java/io/github/lonamiwebs/overgram/parser/TLArg.java b/generator/src/main/java/io/github/lonamiwebs/overgram/parser/TLArg.java
index 9a41bf5..830b703 100644
--- a/generator/src/main/java/io/github/lonamiwebs/overgram/parser/TLArg.java
+++ b/generator/src/main/java/io/github/lonamiwebs/overgram/parser/TLArg.java
@@ -158,6 +158,17 @@ public class TLArg {
         return builder.toString();
     }
 
+    public int bigIntSize() {
+        switch (types.get(types.size() - 1)) {
+            case "int128":
+                return 32;
+            case "int256":
+                return 64;
+            default:
+                return 0;
+        }
+    }
+
     public String javaSetCheck() {
         return types.size() == 1 && types.get(0).equals("true") ? "" : " != null";
     }
diff --git a/lib/src/main/java/io/github/lonamiwebs/overgram/Overgram.java b/lib/src/main/java/io/github/lonamiwebs/overgram/Overgram.java
index 8807b08..95ecb20 100644
--- a/lib/src/main/java/io/github/lonamiwebs/overgram/Overgram.java
+++ b/lib/src/main/java/io/github/lonamiwebs/overgram/Overgram.java
@@ -3,14 +3,19 @@ package io.github.lonamiwebs.overgram;
 import io.github.lonamiwebs.overgram.network.MTProtoSender;
 import io.github.lonamiwebs.overgram.network.MTProtoState;
 import io.github.lonamiwebs.overgram.network.connection.TcpFull;
+import io.github.lonamiwebs.overgram.tl.Functions;
 
 import java.io.IOException;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
 
 public class Overgram {
-    public static void main(final String... args) throws IOException {
+    public static void main(final String... args) throws IOException, InterruptedException, ExecutionException {
         final MTProtoSender sender = new MTProtoSender(new MTProtoState(), new TcpFull());
         try {
             sender.connect("149.154.167.91", 443);
+            final Future result = sender.send(new Functions.help.GetConfig());
+            System.out.println(result.get());
         } finally {
             sender.disconnect();
         }
diff --git a/lib/src/main/java/io/github/lonamiwebs/overgram/crypto/AuthKey.java b/lib/src/main/java/io/github/lonamiwebs/overgram/crypto/AuthKey.java
index ea28eec..9aa70b6 100644
--- a/lib/src/main/java/io/github/lonamiwebs/overgram/crypto/AuthKey.java
+++ b/lib/src/main/java/io/github/lonamiwebs/overgram/crypto/AuthKey.java
@@ -1,10 +1,12 @@
 package io.github.lonamiwebs.overgram.crypto;
 
+import io.github.lonamiwebs.overgram.utils.BinaryWriter;
 import io.github.lonamiwebs.overgram.utils.Utils;
 
 import java.math.BigInteger;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.util.Arrays;
 
 public class AuthKey {
     public final byte[] key;
@@ -21,20 +23,12 @@ public class AuthKey {
     }
 
     public BigInteger calcNewNonceHash(final BigInteger newNonce, final int number) {
-        // Big integer is big endian but we need little endian
-        final byte[] data = Utils.sha1digest(Utils.concat(
-                Utils.reversed(newNonce.toByteArray()), Utils.concat(
-                        ByteBuffer.allocate(1).put((byte) number).array(),
-                        ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN).putLong(auxHash).array()
-                )
-        ));
+        final BinaryWriter writer = new BinaryWriter(41);
+        writer.write(newNonce, 32);
+        writer.write((byte) number);
+        writer.write(auxHash);
 
-        // Little endian once again so read (20..4]
-        final byte[] numberBytes = new byte[16];
-        for (int i = 16; i-- != 0; ) {
-            numberBytes[i] = data[19 - i];
-        }
-
-        return new BigInteger(numberBytes);
+        final byte[] sha = Utils.sha1digest(writer.toBytes());
+        return new BigInteger(Utils.reversed(Arrays.copyOfRange(sha, 4, 20)));
     }
 }
diff --git a/lib/src/main/java/io/github/lonamiwebs/overgram/network/MTProtoSender.java b/lib/src/main/java/io/github/lonamiwebs/overgram/network/MTProtoSender.java
index 638b731..2cdbf35 100644
--- a/lib/src/main/java/io/github/lonamiwebs/overgram/network/MTProtoSender.java
+++ b/lib/src/main/java/io/github/lonamiwebs/overgram/network/MTProtoSender.java
@@ -211,7 +211,12 @@ public class MTProtoSender {
                 return;
             }
 
-            final TLMessage message = state.unpackMessage(body);
+            final TLMessage message;
+            try {
+                message = state.unpackMessage(body);
+            } catch (ClassNotFoundException ignored) {
+                continue;
+            }
             try {
                 processMessage(message);
             } catch (InterruptedException ignored) {
diff --git a/lib/src/main/java/io/github/lonamiwebs/overgram/network/MTProtoState.java b/lib/src/main/java/io/github/lonamiwebs/overgram/network/MTProtoState.java
index 2a9ea49..18bae40 100644
--- a/lib/src/main/java/io/github/lonamiwebs/overgram/network/MTProtoState.java
+++ b/lib/src/main/java/io/github/lonamiwebs/overgram/network/MTProtoState.java
@@ -1,10 +1,18 @@
 package io.github.lonamiwebs.overgram.network;
 
+import io.github.lonamiwebs.overgram.crypto.AES;
 import io.github.lonamiwebs.overgram.crypto.AuthKey;
 import io.github.lonamiwebs.overgram.tl.TLMessage;
 import io.github.lonamiwebs.overgram.tl.TLObject;
+import io.github.lonamiwebs.overgram.tl.TLRequest;
+import io.github.lonamiwebs.overgram.utils.BinaryReader;
+import io.github.lonamiwebs.overgram.utils.BinaryWriter;
+import io.github.lonamiwebs.overgram.utils.Utils;
+import javafx.util.Pair;
 
+import java.nio.ByteBuffer;
 import java.security.SecureRandom;
+import java.util.Arrays;
 
 public class MTProtoState {
 
@@ -25,19 +33,93 @@ public class MTProtoState {
     }
 
     public TLMessage createMessage(final TLObject object) {
-        throw new UnsupportedOperationException();
+        return new TLMessage(getNewMsgId(), getSeqNo(object instanceof TLRequest), object);
     }
 
-    public static Object calcKey(final Object authKey, final byte[] msgKey, final boolean client) {
-        throw new UnsupportedOperationException();
+    private Pair<byte[], byte[]> calcKey(final byte[] msgKey, final boolean client) {
+        final int x = client ? 0 : 8;
+        final byte[] sha256a = Utils.sha256digest(msgKey, ByteBuffer.wrap(authKey.key, x, 36).array());
+        final byte[] sha256b = Utils.sha256digest(ByteBuffer.wrap(authKey.key, x + 40, 36).array(), msgKey);
+
+        final BinaryWriter writer = new BinaryWriter(32);
+        writer.writeRaw(sha256a, 0, 8);
+        writer.writeRaw(sha256b, 8, 16);
+        writer.writeRaw(sha256a, 24, 8);
+        final byte[] key = writer.toBytes();
+        writer.clear();
+        writer.writeRaw(sha256b, 0, 8);
+        writer.writeRaw(sha256a, 8, 16);
+        writer.writeRaw(sha256b, 24, 8);
+
+        return new Pair<>(key, writer.toBytes());
     }
 
     public byte[] packMessage(final TLMessage message) {
-        throw new UnsupportedOperationException();
+        final BinaryWriter writer = new BinaryWriter();
+        writer.write(salt);
+        writer.write(id);
+        writer.write(message);
+
+        int padding = writer.size() % 16;
+        if (padding != 0) {
+            writer.writeRaw(Utils.randomBytes(16 - padding));
+        }
+
+        final byte[] paddedData = writer.toBytes();
+        writer.clear();
+
+        final byte[] msgKeyLarge = Utils.sha256digest(
+                Arrays.copyOfRange(authKey.key, 88, 88 + 32), paddedData);
+
+        final byte[] msgKey = Arrays.copyOfRange(msgKeyLarge, 8, 24);
+        final Pair<byte[], byte[]> keyIv = calcKey(msgKey, true);
+
+        writer.write(authKey.keyId);
+        writer.writeRaw(msgKey);
+        writer.writeRaw(AES.encryptIge(paddedData, keyIv.getKey(), keyIv.getValue()));
+        return writer.toBytes();
     }
 
-    public TLMessage unpackMessage(final byte[] body) {
-        throw new UnsupportedOperationException();
+    public TLMessage unpackMessage(final byte[] body) throws ClassNotFoundException {
+        if (body.length < 8) {
+            if (body[0] == (byte) 0x6c
+                    && body[1] == (byte) 0xfe
+                    && body[2] == (byte) 0xff
+                    && body[3] == (byte) 0xff) {
+                // -404 as little endian, broken authorization
+                throw new RuntimeException();
+            } else {
+                throw new RuntimeException();
+            }
+        }
+
+        final BinaryReader reader = new BinaryReader(ByteBuffer.wrap(body));
+        final long keyId = reader.readLong();
+        if (keyId != authKey.keyId) {
+            throw new SecurityException("Server replied with an invalid auth key");
+        }
+
+        final byte[] msgKey = reader.read(16);
+        final Pair<byte[], byte[]> keyIv = calcKey(msgKey, false);
+        final byte[] plainText = AES.decryptIge(reader.read(), keyIv.getKey(), keyIv.getValue());
+
+        final byte[] ourKey = Utils.sha256digest(ByteBuffer.wrap(authKey.key, 96, 32).array(), body);
+        if (!Arrays.equals(msgKey, ourKey)) {
+            throw new SecurityException("Received message key doesn't match with expected one");
+        }
+
+        final BinaryReader tlReader = new BinaryReader(ByteBuffer.wrap(plainText));
+        tlReader.readLong(); // remote salt
+        if (tlReader.readLong() != id) {
+            throw new SecurityException("Server replied with a wrong session ID");
+        }
+
+        final long remoteMsgId = reader.readLong();
+        final int remoteSeq = reader.readInt();
+        reader.readInt(); // inner message length
+
+        final TLObject object = reader.readTl();
+        return new TLMessage(remoteMsgId, remoteSeq, object);
     }
 
     public long getNewMsgId() {
diff --git a/lib/src/main/java/io/github/lonamiwebs/overgram/tl/TLMessage.java b/lib/src/main/java/io/github/lonamiwebs/overgram/tl/TLMessage.java
index 3c50f44..4410f74 100644
--- a/lib/src/main/java/io/github/lonamiwebs/overgram/tl/TLMessage.java
+++ b/lib/src/main/java/io/github/lonamiwebs/overgram/tl/TLMessage.java
@@ -1,10 +1,36 @@
 package io.github.lonamiwebs.overgram.tl;
 
+import io.github.lonamiwebs.overgram.utils.BinaryReader;
+import io.github.lonamiwebs.overgram.utils.BinaryWriter;
+
 import java.util.concurrent.CompletableFuture;
 
-public class TLMessage {
+public class TLMessage extends TLObject {
     public CompletableFuture<Object> future;
-    public long id;
 
+    public long id;
+    public int seqNo;
     public TLObject object;
+
+    public TLMessage(final long id, final int seqNo, final TLObject object) {
+        this.id = id;
+        this.seqNo = seqNo;
+        this.object = object;
+        future = new CompletableFuture<>();
+    }
+
+    @Override
+    public void serialize(BinaryWriter writer) {
+        final BinaryWriter tmp = new BinaryWriter();
+        tmp.write(object);
+        writer.write(id);
+        writer.write(seqNo);
+        writer.write(tmp.size());
+        writer.writeRaw(tmp.toBytes());
+    }
+
+    @Override
+    public void deserialize(BinaryReader reader) throws ClassNotFoundException {
+        throw new UnsupportedOperationException();
+    }
 }
diff --git a/lib/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryReader.java b/lib/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryReader.java
index 55f8dc6..08b06f4 100644
--- a/lib/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryReader.java
+++ b/lib/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryReader.java
@@ -129,4 +129,16 @@ public class BinaryReader {
     public void seek(final int delta) {
         buffer.position(buffer.position() + delta);
     }
+
+    public byte[] read(final int size) {
+        final byte[] result = new byte[size];
+        buffer.get(result);
+        return result;
+    }
+
+    public byte[] read() {
+        final byte[] result = new byte[buffer.remaining()];
+        buffer.get(result);
+        return result;
+    }
 }
diff --git a/lib/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryWriter.java b/lib/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryWriter.java
index 0e92c3f..464f01f 100644
--- a/lib/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryWriter.java
+++ b/lib/src/main/java/io/github/lonamiwebs/overgram/utils/BinaryWriter.java
@@ -22,6 +22,14 @@ public class BinaryWriter {
         buffer = new ByteArrayOutputStream(128);
     }
 
+    public BinaryWriter(final int capacity) {
+        buffer = new ByteArrayOutputStream(capacity);
+    }
+
+    public void write(final byte value) {
+        buffer.write(value);
+    }
+
     public void write(final int value) {
         try {
             buffer.write(ByteBuffer.allocate(4).order(ORDER).putInt(value).array());
@@ -38,20 +46,21 @@ public class BinaryWriter {
         }
     }
 
-    public void write(final BigInteger value) {
+    public void write(final BigInteger value, final int size) {
         final byte[] bytes = value.toByteArray();
-
-        // It's really unlike an int256 has only 16 bytes so we're good
-        final int size = bytes.length > 16 ? 32 : 16;
-        if (ORDER == ByteOrder.BIG_ENDIAN) {
-            for (int i = 0; i < size; ++i) {
-                buffer.write(i < bytes.length ? bytes[i] : 0);
-            }
+        final byte[] result;
+        if (bytes.length == size) {
+            result = bytes;
         } else {
-            for (int i = size; i-- != 0; ) {
-                buffer.write(i < bytes.length ? bytes[i] : 0);
+            result = new byte[size];
+            final byte fill = value.signum() > 0 ? 0 : (byte) 0xff;
+            System.arraycopy(bytes, 0, result, size - bytes.length, bytes.length);
+            for (int i = size - bytes.length; i-- != 0; ) {
+                result[i] = fill;
             }
         }
+
+        buffer.write(ORDER == ByteOrder.BIG_ENDIAN ? result : Utils.reversed(result), 0, size);
     }
 
     public void write(final double value) {
@@ -89,10 +98,11 @@ public class BinaryWriter {
     }
 
     public void writeRaw(final byte[] bytes) {
-        try {
-            buffer.write(bytes);
-        } catch (IOException ignored) {
-        }
+        buffer.write(bytes, 0, bytes.length);
+    }
+
+    public void writeRaw(final byte[] bytes, final int start, final int length) {
+        buffer.write(bytes, start, length);
     }
 
     public void write(final String string) {
diff --git a/lib/src/main/java/io/github/lonamiwebs/overgram/utils/Utils.java b/lib/src/main/java/io/github/lonamiwebs/overgram/utils/Utils.java
index b9fe5c3..ef40efb 100644
--- a/lib/src/main/java/io/github/lonamiwebs/overgram/utils/Utils.java
+++ b/lib/src/main/java/io/github/lonamiwebs/overgram/utils/Utils.java
@@ -11,6 +11,7 @@ import java.util.Arrays;
 public class Utils {
 
     private static MessageDigest sha1;
+    private static MessageDigest sha256;
     private static SecureRandom random;
 
     static {
@@ -19,6 +20,10 @@ public class Utils {
             sha1 = MessageDigest.getInstance("SHA-1");
         } catch (NoSuchAlgorithmException ignored) {
         }
+        try {
+            sha256 = MessageDigest.getInstance("SHA-256");
+        } catch (NoSuchAlgorithmException ignored) {
+        }
     }
 
     public static BigInteger randomBigInteger(final BigInteger max) {
@@ -112,16 +117,32 @@ public class Utils {
         return new Pair<>(x.min(y), x.max(y));
     }
 
-    public static byte[] sha1digest(final byte[] data) throws SecurityException {
+    public static byte[] sha1digest(final byte[]... data) throws SecurityException {
         if (sha1 == null) {
             throw new SecurityException("SHA-1 is required but not available");
         }
 
-        final byte[] result = sha1.digest(data);
+        for (final byte[] datum : data) {
+            sha1.update(datum);
+        }
+        final byte[] result = sha1.digest();
         sha1.reset();
         return result;
     }
 
+    public static byte[] sha256digest(final byte[]... data) throws SecurityException {
+        if (sha256 == null) {
+            throw new SecurityException("SHA-256 is required but not available");
+        }
+
+        for (final byte[] datum : data) {
+            sha256.update(datum);
+        }
+        final byte[] result = sha256.digest();
+        sha256.reset();
+        return result;
+    }
+
     public static Pair<byte[], byte[]> generateKeyDataFromNonce(BigInteger serverNonce, BigInteger newNonce) {
         final byte[] serverNonceBytes = reversed(serverNonce.toByteArray());
         final byte[] newNonceBytes = reversed(newNonce.toByteArray());