Merge branch 'query_signer' of github.com:m-chrzan/CloudAtlas into query_signer

12 files changed, 520 insertions, 32 deletions

diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/ByteSerializer.java b/src/main/java/pl/edu/mimuw/cloudatlas/ByteSerializer.java
new file mode 100644
index 0000000..ee7a6f0
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/ByteSerializer.java
@@ -0,0 +1,182 @@
+package pl.edu.mimuw.cloudatlas;
+
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.Serializer;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+import pl.edu.mimuw.cloudatlas.agent.messages.*;
+import pl.edu.mimuw.cloudatlas.agent.modules.ModuleType;
+import pl.edu.mimuw.cloudatlas.agent.modules.RecursiveScheduledTask;
+import pl.edu.mimuw.cloudatlas.agent.modules.TimerScheduledTask;
+import pl.edu.mimuw.cloudatlas.model.*;
+import pl.edu.mimuw.cloudatlas.querysigner.QueryData;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.rmi.Remote;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+
+/**
+ * Serializes classes to and from byte arrays
+ */
+// TODO remove udupserializer
+public class ByteSerializer {
+    private Kryo kryo;
+
+    public ByteSerializer() {
+        kryo = new Kryo();
+        kryo.setReferences(true);
+        kryo.setRegistrationRequired(true);
+        registerClasses();
+    }
+
+    private void registerClasses() {
+
+        kryo.register(Inet4Address.class, new Serializer() {
+
+            @Override
+            public void write(Kryo kryo, Output output, Object object) {
+                InetAddress ia = (InetAddress) object;
+                kryo.writeObject(output, ia.getAddress());
+            }
+
+            @Override
+            public Object read(Kryo kryo, Input input, Class type) {
+                try {
+                    byte[] buf = kryo.readObject(input, byte[].class);
+                    InetAddress addr = Inet4Address.getByAddress(buf);
+                    return addr;
+                } catch (UnknownHostException e) {
+                    System.out.println("Custom InetAddress read failed");
+                    e.printStackTrace();
+                    return null;
+                }
+            }
+        });
+
+        kryo.register(PathName.class, new Serializer() {
+
+            @Override
+            public void write(Kryo kryo, Output output, Object object) {
+                PathName pn = (PathName) object;
+                kryo.writeObject(output, pn.getName());
+            }
+
+            @Override
+            public Object read(Kryo kryo, Input input, Class type) {
+                String addr = input.readString();
+                return new PathName(addr);
+            }
+        });
+
+        kryo.register(ValueList.class, new Serializer() {
+            @Override
+            public void write(Kryo kryo, Output output, Object object) {
+                ValueList vl = (ValueList) object;
+                kryo.writeObject(output, ((TypeCollection) vl.getType()).getElementType());
+                kryo.writeObject(output, vl.getValue());
+            }
+
+            @Override
+            public Object read(Kryo kryo, Input input, Class type) {
+                Type t = kryo.readObject(input, Type.class);
+                ArrayList list = kryo.readObject(input, ArrayList.class);
+                return new ValueList(list, t);
+            }
+        });
+
+        kryo.register(ValueSet.class, new Serializer() {
+            @Override
+            public void write(Kryo kryo, Output output, Object object) {
+                ValueSet vs = (ValueSet) object;
+                kryo.writeObject(output, ((TypeCollection) vs.getType()).getElementType());
+                kryo.writeObject(output, vs.getValue());
+            }
+
+            @Override
+            public Object read(Kryo kryo, Input input, Class type) {
+                Type t = kryo.readObject(input, Type.class);
+                HashSet set = kryo.readObject(input, HashSet.class);
+                return new ValueSet(set, t);
+            }
+        });
+
+        // model
+        kryo.register(Value.class);
+        kryo.register(ValueBoolean.class);
+        kryo.register(ValueContact.class);
+        kryo.register(ValueDuration.class);
+        kryo.register(ValueInt.class);
+        kryo.register(ValueNull.class);
+        kryo.register(ValueQuery.class);
+        kryo.register(ValueSet.class);
+        kryo.register(ValueString.class);
+        kryo.register(ValueTime.class);
+        kryo.register(ValueUtils.class);
+        kryo.register(ZMI.class);
+
+        kryo.register(Attribute.class);
+        kryo.register(AttributesMap.class);
+        kryo.register(AttributesUtil.class);
+
+        kryo.register(Type.class);
+        kryo.register(TypeCollection.class);
+        kryo.register(TypePrimitive.class);
+
+        // messages in chronological order so it's easier to keep track
+        kryo.register(AgentMessage.class);
+        kryo.register(AttributesMessage.class);
+        kryo.register(GetStateMessage.class);
+        kryo.register(HejkaMessage.class);
+        kryo.register(NoCoTamMessage.class);
+        kryo.register(QueryMessage.class);
+        kryo.register(QurnikMessage.class);
+        kryo.register(RemikMessage.class);
+        kryo.register(RemoveZMIMessage.class);
+        kryo.register(RequestStateMessage.class);
+        kryo.register(ResponseMessage.class);
+        kryo.register(RunQueriesMessage.class);
+        kryo.register(SetAttributeMessage.class);
+        kryo.register(StanikMessage.Type.class);
+        kryo.register(StanikMessage.class);
+        kryo.register(TimerSchedulerMessage.class);
+        kryo.register(UDUPMessage.class);
+        kryo.register(UpdateAttributesMessage.class);
+        kryo.register(UpdateQueriesMessage.class);
+        kryo.register(GossipGirlMessage.class);
+        kryo.register(GossipGirlMessage.Type.class);
+        kryo.register(RemoteGossipGirlMessage.class);
+
+        // modules
+        kryo.register(TimerScheduledTask.class);
+        kryo.register(RecursiveScheduledTask.class);
+
+        // other
+        kryo.register(byte[].class);
+        kryo.register(LinkedHashMap.class);
+        kryo.register(HashMap.class);
+        kryo.register(ModuleType.class);
+        kryo.register(QueryData.class);
+    }
+
+    public Object deserialize(byte[] packetData, Class objClass) {
+        ByteArrayInputStream in = new ByteArrayInputStream(packetData);
+        Input kryoInput = new Input(in);
+        return kryo.readObject(kryoInput, objClass);
+    }
+
+    public byte[] serialize(Object obj) {
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        Output kryoOut = new Output(out);
+        kryo.writeObject(kryoOut, obj);
+        kryoOut.flush();
+        kryoOut.close();
+        return out.toByteArray();
+    }
+}
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/agent/ApiImplementation.java b/src/main/java/pl/edu/mimuw/cloudatlas/agent/ApiImplementation.java
index d2e808a..90e7789 100644
--- a/src/main/java/pl/edu/mimuw/cloudatlas/agent/ApiImplementation.java
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/agent/ApiImplementation.java
@@ -28,6 +28,8 @@ import pl.edu.mimuw.cloudatlas.model.Type;
 import pl.edu.mimuw.cloudatlas.model.TypePrimitive;
 import pl.edu.mimuw.cloudatlas.model.ZMI;
 import pl.edu.mimuw.cloudatlas.api.Api;
+import pl.edu.mimuw.cloudatlas.querysigner.QueryData;
+import pl.edu.mimuw.cloudatlas.querysigner.QueryUtils;
 
 public class ApiImplementation implements Api {
     ZMI root;
@@ -60,16 +62,11 @@ public class ApiImplementation implements Api {
         }
     }
 
-    public void installQuery(String name, String queryCode) throws RemoteException {
-        Pattern queryNamePattern = Pattern.compile("&[a-zA-Z][\\w_]*");
-        Matcher matcher = queryNamePattern.matcher(name);
-        if (!matcher.matches()) {
-            throw new RemoteException("Invalid query identifier");
-        }
+    public void installQuery(String name, QueryData query) throws RemoteException {
+        QueryUtils.validateQueryName(name);
         try {
-            ValueQuery query = new ValueQuery(queryCode);
             Attribute attributeName = new Attribute(name);
-            installQueryInHierarchy(root, attributeName, query);
+            installQueryInHierarchy(root, attributeName, new ValueQuery(query));
             executeAllQueries(root);
         } catch (Exception e) {
             throw new RemoteException("Failed to install query", e);
@@ -85,7 +82,8 @@ public class ApiImplementation implements Api {
         }
     }
 
-    public void uninstallQuery(String queryName) throws RemoteException {
+    public void uninstallQuery(String queryName, QueryData query) throws RemoteException {
+        QueryUtils.validateQueryName(queryName);
         uninstallQueryInHierarchy(root, new Attribute(queryName));
     }
 
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/agent/NewApiImplementation.java b/src/main/java/pl/edu/mimuw/cloudatlas/agent/NewApiImplementation.java
index b293446..0bf4338 100644
--- a/src/main/java/pl/edu/mimuw/cloudatlas/agent/NewApiImplementation.java
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/agent/NewApiImplementation.java
@@ -22,6 +22,8 @@ import pl.edu.mimuw.cloudatlas.interpreter.Main;
 import pl.edu.mimuw.cloudatlas.interpreter.QueryResult;
 import pl.edu.mimuw.cloudatlas.model.*;
 import pl.edu.mimuw.cloudatlas.api.Api;
+import pl.edu.mimuw.cloudatlas.querysigner.QueryData;
+import pl.edu.mimuw.cloudatlas.querysigner.QueryUtils;
 
 public class NewApiImplementation implements Api {
     private EventBus eventBus;
@@ -79,18 +81,13 @@ public class NewApiImplementation implements Api {
         }
     }
 
-    public void installQuery(String name, String queryCode) throws RemoteException {
-        Pattern queryNamePattern = Pattern.compile("&[a-zA-Z][\\w_]*");
-        Matcher matcher = queryNamePattern.matcher(name);
-        if (!matcher.matches()) {
-            throw new RemoteException("Invalid query identifier");
-        }
+    public void installQuery(String name, QueryData query) throws RemoteException {
+        QueryUtils.validateQueryName(name);
         try {
-            ValueQuery query = new ValueQuery(queryCode);
             Attribute attributeName = new Attribute(name);
             ValueTime timestamp = new ValueTime(System.currentTimeMillis());
             Map<Attribute, Entry<ValueQuery, ValueTime>> queries = new HashMap();
-            queries.put(attributeName, new SimpleImmutableEntry(query, timestamp));
+            queries.put(attributeName, new SimpleImmutableEntry(new ValueQuery(query), timestamp));
             UpdateQueriesMessage message = new UpdateQueriesMessage("", 0, queries);
             eventBus.addMessage(message);
         } catch (Exception e) {
@@ -98,7 +95,8 @@ public class NewApiImplementation implements Api {
         }
     }
 
-    public void uninstallQuery(String queryName) throws RemoteException {
+    public void uninstallQuery(String queryName, QueryData query) throws RemoteException {
+        QueryUtils.validateQueryName(queryName);
         try {
             Attribute attributeName = new Attribute(queryName);
             ValueTime timestamp = new ValueTime(System.currentTimeMillis());
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/api/Api.java b/src/main/java/pl/edu/mimuw/cloudatlas/api/Api.java
index c62ee39..7cc629d 100644
--- a/src/main/java/pl/edu/mimuw/cloudatlas/api/Api.java
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/api/Api.java
@@ -6,6 +6,8 @@ import java.rmi.RemoteException;
 import pl.edu.mimuw.cloudatlas.model.Value;
 import pl.edu.mimuw.cloudatlas.model.ValueContact;
 import pl.edu.mimuw.cloudatlas.model.AttributesMap;
+import pl.edu.mimuw.cloudatlas.model.ValueQuery;
+import pl.edu.mimuw.cloudatlas.querysigner.QueryData;
 
 /**
  *
@@ -27,9 +29,9 @@ public interface Api extends Remote {
 
     public AttributesMap getZoneAttributeValues(String zoneName) throws RemoteException;
 
-    public void installQuery(String queryName, String query) throws RemoteException;
+    public void installQuery(String queryName, QueryData query) throws RemoteException;
 
-    public void uninstallQuery(String queryName) throws RemoteException;
+    public void uninstallQuery(String queryName, QueryData query) throws RemoteException;
 
     public void setAttributeValue(String zoneName, String attributeName, Value value) throws RemoteException;
 
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/client/ClientController.java b/src/main/java/pl/edu/mimuw/cloudatlas/client/ClientController.java
index 4019696..5f34fe9 100644
--- a/src/main/java/pl/edu/mimuw/cloudatlas/client/ClientController.java
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/client/ClientController.java
@@ -7,6 +7,8 @@ import org.springframework.web.bind.annotation.*;
 import org.springframework.stereotype.Controller;
 import pl.edu.mimuw.cloudatlas.api.Api;
 import pl.edu.mimuw.cloudatlas.model.*;
+import pl.edu.mimuw.cloudatlas.querysigner.QueryData;
+import pl.edu.mimuw.cloudatlas.querysignerapi.QuerySignerApi;
 
 import java.net.InetAddress;
 import java.rmi.registry.LocateRegistry;
@@ -32,17 +34,21 @@ import java.util.*;
 
 @Controller
 public class ClientController {
-    private Api api;
-
+    private Api agentApi;
+    private QuerySignerApi querySignerApi;
     private Map<ValueTime, AttributesMap> attributes;
     private String currentZoneName;
     private static final int MAX_ENTRIES = 10;
 
     ClientController() {
         try {
-            String hostname = System.getProperty("agent_hostname");	
-            Registry registry = LocateRegistry.getRegistry(hostname);
-            this.api = (Api) registry.lookup("Api");
+            String agentHostname = System.getProperty("agent_hostname");
+            Registry registry = LocateRegistry.getRegistry(agentHostname);
+            this.agentApi = (Api) registry.lookup("Api");
+
+            String querySignerHostname = System.getProperty("querysigner_hostname");
+            Registry querySignerRegistry = LocateRegistry.getRegistry(querySignerHostname);
+            this.querySignerApi = (QuerySignerApi) querySignerRegistry.lookup("QuerySignerApi");
         } catch (Exception e) {
             System.err.println("Client exception:");
             e.printStackTrace();
@@ -74,7 +80,8 @@ public class ClientController {
         boolean success = true;
 
         try {
-            this.api.installQuery(queryObject.getName(), queryObject.getValue());
+            QueryData query = this.querySignerApi.signInstallQuery(queryObject.getName(), queryObject.getValue());
+            this.agentApi.installQuery(queryObject.getName(), query);
         } catch (Exception e) {
             success = false;
             System.err.println("Client exception:");
@@ -99,7 +106,8 @@ public class ClientController {
         boolean success = true;
 
         try {
-            this.api.uninstallQuery(queryObject.getName());
+            QueryData query = querySignerApi.signUninstallQuery(queryObject.getName());
+            this.agentApi.uninstallQuery(queryObject.getName(), query);
         } catch (Exception e) {
             success = false;
             System.err.println("Client exception:");
@@ -153,7 +161,7 @@ public class ClientController {
 
         try {
             contactObjects = parseContactsString(contactsObject);
-            this.api.setFallbackContacts(contactObjects);
+            this.agentApi.setFallbackContacts(contactObjects);
         } catch (Exception e) {
             success = false;
             System.err.println("Client exception:");
@@ -284,7 +292,7 @@ public class ClientController {
 
         try {
             attributeValue = parseAttributeValue(attributeObject);
-            api.setAttributeValue(
+            agentApi.setAttributeValue(
                     attributeObject.getZoneName(),
                     attributeObject.getAttributeName(),
                     attributeValue);
@@ -309,7 +317,7 @@ public class ClientController {
         String availableZonesString = "";
 
         try {
-            availableZones = api.getZoneSet();
+            availableZones = agentApi.getZoneSet();
             availableZonesString = availableZones.toString().substring(1, availableZones.toString().length() - 1);
         } catch (Exception e) {
             success = false;
@@ -336,7 +344,7 @@ public class ClientController {
 
         try {
             if (!this.currentZoneName.isEmpty()) {
-                attribData = api.getZoneAttributeValues(this.currentZoneName);
+                attribData = agentApi.getZoneAttributeValues(this.currentZoneName);
                 currentTime = new ValueTime(System.currentTimeMillis());
                 this.attributes.put(currentTime, attribData);
             }
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/model/ValueQuery.java b/src/main/java/pl/edu/mimuw/cloudatlas/model/ValueQuery.java
index 6d233ea..ece50b5 100644
--- a/src/main/java/pl/edu/mimuw/cloudatlas/model/ValueQuery.java
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/model/ValueQuery.java
@@ -6,6 +6,7 @@ import pl.edu.mimuw.cloudatlas.interpreter.query.Absyn.Program;
 import pl.edu.mimuw.cloudatlas.interpreter.query.parser;
 import pl.edu.mimuw.cloudatlas.interpreter.query.Yylex;
 import pl.edu.mimuw.cloudatlas.model.Value;
+import pl.edu.mimuw.cloudatlas.querysigner.QueryData;
 
 /**
  * A class that holds a CloudAtlas query.
@@ -15,21 +16,45 @@ public class ValueQuery extends Value {
     private String code;
     // Parsed query
     private Program query;
+    // Query signature
+    private byte[] signature;
+    // Query signing timestamp
+    private long timestamp;
+
     /**
      * Constructs a new <code>ValueQuery</code> object.
      *
-     * @param name the name of the query
      * @param query the code of the query
      */
     public ValueQuery(String query) throws Exception {
         this.code = query;
         Yylex lex = new Yylex(new ByteArrayInputStream(query.getBytes()));
         this.query = (new parser(lex)).pProgram();
+        this.signature = null;
+        this.timestamp = System.currentTimeMillis();
+    }
+
+    public ValueQuery(String query, byte[] querySignature) throws Exception {
+        this.code = query;
+        Yylex lex = new Yylex(new ByteArrayInputStream(query.getBytes()));
+        this.query = (new parser(lex)).pProgram();
+        this.signature = querySignature;
+        this.timestamp = System.currentTimeMillis();
+    }
+
+    public ValueQuery(QueryData queryData) throws Exception {
+        this.code = queryData.getCode();
+        Yylex lex = new Yylex(new ByteArrayInputStream(queryData.getCode().getBytes()));
+        this.query = (new parser(lex)).pProgram();
+        this.signature = queryData.getSignature();
+        this.timestamp = System.currentTimeMillis();
     }
 
     private ValueQuery() {
         this.code = null;
         this.query = null;
+        this.signature = null;
+        this.timestamp = System.currentTimeMillis();
     }
 
     public String getCode() { return code; }
@@ -38,6 +63,12 @@ public class ValueQuery extends Value {
         return query;
     }
 
+    public byte[] getSignature() { return signature; }
+
+    public long getTimestamp() { return timestamp; }
+
+    public void setTimestamp(long timestamp) { this.timestamp = timestamp; }
+
     @Override
     public Type getType() {
         return TypePrimitive.QUERY;
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/KeyUtils.java b/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/KeyUtils.java
new file mode 100644
index 0000000..7a543ba
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/KeyUtils.java
@@ -0,0 +1,35 @@
+package pl.edu.mimuw.cloudatlas.querysigner;
+
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.security.*;
+import java.security.spec.PKCS8EncodedKeySpec;
+import java.security.spec.X509EncodedKeySpec;
+
+public class KeyUtils {
+    private final static String ENCRYPTION_ALGORITHM = "RSA";
+
+    public static PublicKey getPublicKey(String filename){
+        try {
+            byte[] byteKey = Files.readAllBytes(Paths.get(filename));
+            X509EncodedKeySpec X509publicKey = new X509EncodedKeySpec(byteKey);
+            KeyFactory kf = KeyFactory.getInstance(ENCRYPTION_ALGORITHM);
+            return kf.generatePublic(X509publicKey);
+        } catch(Exception e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    public static PrivateKey getPrivateKey(String filename){
+        try {
+            byte[] byteKey = Files.readAllBytes(Paths.get(filename));
+            PKCS8EncodedKeySpec PKCS8privateKey = new PKCS8EncodedKeySpec(byteKey);
+            KeyFactory kf = KeyFactory.getInstance(ENCRYPTION_ALGORITHM);
+            return kf.generatePrivate(PKCS8privateKey);
+        } catch(Exception e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+}
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QueryData.java b/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QueryData.java
new file mode 100644
index 0000000..7801a28
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QueryData.java
@@ -0,0 +1,30 @@
+package pl.edu.mimuw.cloudatlas.querysigner;
+
+import java.io.Serializable;
+
+public class QueryData implements Serializable {
+    // Original source code
+    private String code;
+    // Query signature
+    private byte[] signature;
+    // Query signing timestamp
+    private long timestamp;
+
+    public QueryData(String code, byte[] signature) {
+        this.code = code;
+        this.signature = signature;
+        this.timestamp = System.currentTimeMillis();;
+    }
+
+    public String getCode() {
+        return code;
+    }
+
+    public byte[] getSignature() {
+        return signature;
+    }
+
+    public long getTimestamp() {
+        return timestamp;
+    }
+}
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QuerySigner.java b/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QuerySigner.java
new file mode 100644
index 0000000..735601d
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QuerySigner.java
@@ -0,0 +1,44 @@
+package pl.edu.mimuw.cloudatlas.querysigner;
+
+import pl.edu.mimuw.cloudatlas.querysignerapi.QuerySignerApi;
+
+import java.io.IOException;
+import java.rmi.registry.LocateRegistry;
+import java.rmi.registry.Registry;
+import java.rmi.server.UnicastRemoteObject;
+import java.security.PrivateKey;
+import java.security.PublicKey;
+
+public class QuerySigner {
+    public static class InvalidQueryException extends Exception {
+        InvalidQueryException() {
+            super("Query invalid");
+        }
+    }
+
+    private static QuerySignerApiImplementation initApi() throws IOException {
+        String publicKeyFile = System.getProperty("public_key_file");
+        String privateKeyFile = System.getProperty("private_key_file");
+        PublicKey publicKey = KeyUtils.getPublicKey(publicKeyFile);
+        PrivateKey privateKey = KeyUtils.getPrivateKey(privateKeyFile);
+        return new QuerySignerApiImplementation(publicKey, privateKey);
+    }
+
+    public static void runRegistry() {
+        try {
+            QuerySignerApiImplementation api = initApi();
+            QuerySignerApi apiStub =
+                    (QuerySignerApi) UnicastRemoteObject.exportObject(api, 0);
+            Registry registry = LocateRegistry.getRegistry();
+            registry.rebind("QuerySignerApi", apiStub);
+            System.out.println("QuerySigner: api bound");
+        } catch (Exception e) {
+            System.err.println("QuerySigner registry initialization exception:");
+            e.printStackTrace();
+        }
+    }
+
+    public static void main(String[] args) {
+        runRegistry();
+    }
+}
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QuerySignerApiImplementation.java b/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QuerySignerApiImplementation.java
new file mode 100644
index 0000000..32bc634
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QuerySignerApiImplementation.java
@@ -0,0 +1,128 @@
+package pl.edu.mimuw.cloudatlas.querysigner;
+
+import pl.edu.mimuw.cloudatlas.ByteSerializer;
+import pl.edu.mimuw.cloudatlas.model.ValueQuery;
+import pl.edu.mimuw.cloudatlas.querysignerapi.QuerySignerApi;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import java.rmi.RemoteException;
+import java.security.*;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public class QuerySignerApiImplementation implements QuerySignerApi {
+    private final static String ENCRYPTION_ALGORITHM = "RSA";
+    private final static String DIGEST_ALGORITHM = "SHA-256";
+    private PublicKey publicKey;
+    private PrivateKey privateKey;
+    private Map<String, ValueQuery> queries;
+    private Set<String> attribsSetByQueries;
+    private ByteSerializer byteSerializer;
+
+    QuerySignerApiImplementation(PublicKey publicKey, PrivateKey privateKey) {// (byte[] serializedPublicKey, byte[] serializedPrivateKey) {
+        this.byteSerializer = new ByteSerializer();
+//        this.publicKey = (PublicKey) byteSerializer.deserialize(serializedPublicKey, PublicKey.class);
+//        this.privateKey = (PrivateKey) byteSerializer.deserialize(serializedPrivateKey, PrivateKey.class);
+        this.publicKey = publicKey;
+        this.privateKey = privateKey;
+        this.queries = new HashMap<>();
+        this.attribsSetByQueries = new HashSet<>();
+    }
+
+    private String byteArrayToString(byte[] arr, int offset, int len) {
+        StringBuffer sb = new StringBuffer();
+        for (int i = offset, n = Math.min(arr.length, offset + len); i < n; ++i) {
+            String hex = Integer.toHexString(0xFF & arr[i]);
+            if (hex.length() < 2) {
+                sb.append('0');
+            }
+            sb.append(hex);
+        }
+        return sb.toString();
+    }
+
+    private byte[] encryptQuery(byte[] query) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
+        Cipher signCipher = Cipher.getInstance(ENCRYPTION_ALGORITHM);
+        signCipher.init(Cipher.ENCRYPT_MODE, privateKey);
+        byte[] encryptedBytes = signCipher.doFinal(query);
+        System.out.println(
+                "Bytes encrypted with " + ENCRYPTION_ALGORITHM +
+                        ": " + byteArrayToString(
+                        encryptedBytes, 0, encryptedBytes.length));
+        return encryptedBytes;
+    }
+
+    private byte[] decryptQuery(byte[] encryptedQuery) throws NoSuchPaddingException, NoSuchAlgorithmException, BadPaddingException, IllegalBlockSizeException, InvalidKeyException {
+        Cipher verifyCipher = Cipher.getInstance(ENCRYPTION_ALGORITHM);
+        verifyCipher.init(Cipher.DECRYPT_MODE, publicKey);
+        byte[] decryptedBytes = verifyCipher.doFinal(encryptedQuery);
+        System.out.println(
+                "Bytes decrypted with " + ENCRYPTION_ALGORITHM +
+                        ": " + byteArrayToString(
+                        decryptedBytes, 0, decryptedBytes.length));
+        return decryptedBytes;
+    }
+
+    private byte[] cryptographicHash(byte[] serializedQuery) throws NoSuchAlgorithmException {
+        MessageDigest digestGenerator =
+                MessageDigest.getInstance(DIGEST_ALGORITHM);
+        byte[] digest = digestGenerator.digest(serializedQuery);
+        System.out.println(
+                DIGEST_ALGORITHM + " digest: " +
+                        byteArrayToString(
+                                digest, 0, digest.length));
+        return digest;
+    }
+
+    // TODO
+    private byte[] serializeQuery(String queryName, String queryCode) {
+        return byteSerializer.serialize(queryName + queryCode);
+    }
+
+    @Override
+    public QueryData signInstallQuery(String queryName, String queryCode) throws RemoteException {
+        QueryUtils.validateQueryName(queryName);
+        try {
+            byte[] serializedQuery = serializeQuery(queryName, queryCode);
+            byte[] hashedQuery = cryptographicHash(serializedQuery);
+            byte[] querySignature = encryptQuery(hashedQuery);
+            return new QueryData(queryCode, querySignature);
+        } catch (Exception e) {
+            e.printStackTrace();
+            throw new RemoteException(e.getLocalizedMessage());
+        }
+    }
+
+    @Override
+    public void validateInstallQuery(String queryName, QueryData query) throws RemoteException {
+        QueryUtils.validateQueryName(queryName);
+        try {
+            byte[] decryptedQuery = decryptQuery(query.getSignature());
+            byte[] serializedQuery = serializeQuery(queryName, query.getCode());
+            byte[] hashedSerializedQuery = cryptographicHash(serializedQuery);
+            if (hashedSerializedQuery != decryptedQuery) {
+                throw new QuerySigner.InvalidQueryException();
+            }
+        } catch (NoSuchPaddingException | NoSuchAlgorithmException | BadPaddingException | IllegalBlockSizeException | InvalidKeyException | QuerySigner.InvalidQueryException e) {
+            e.printStackTrace();
+            throw new RemoteException(e.getLocalizedMessage());
+        }
+    }
+
+    // TODO
+    @Override
+    public QueryData signUninstallQuery(String queryName) throws RemoteException {
+        return null;
+    }
+
+    // TODO
+    @Override
+    public void validateUninstallQuery(String queryName, QueryData query) throws RemoteException {
+
+    }
+}
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QueryUtils.java b/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QueryUtils.java
new file mode 100644
index 0000000..6ec62f4
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/querysigner/QueryUtils.java
@@ -0,0 +1,16 @@
+package pl.edu.mimuw.cloudatlas.querysigner;
+
+import java.rmi.RemoteException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class QueryUtils {
+
+    public static void validateQueryName(String queryName) throws RemoteException {
+        Pattern queryNamePattern = Pattern.compile("&[a-zA-Z][\\w_]*");
+        Matcher matcher = queryNamePattern.matcher(queryName);
+        if (!matcher.matches()) {
+            throw new RemoteException("Invalid query identifier");
+        }
+    }
+}
diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/querysignerapi/QuerySignerApi.java b/src/main/java/pl/edu/mimuw/cloudatlas/querysignerapi/QuerySignerApi.java
new file mode 100644
index 0000000..6b42d32
--- /dev/null
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/querysignerapi/QuerySignerApi.java
@@ -0,0 +1,16 @@
+package pl.edu.mimuw.cloudatlas.querysignerapi;
+
+import pl.edu.mimuw.cloudatlas.querysigner.QueryData;
+
+import java.rmi.Remote;
+import java.rmi.RemoteException;
+
+public interface QuerySignerApi extends Remote {
+    public QueryData signInstallQuery(String queryName, String queryCode) throws RemoteException;
+
+    public QueryData signUninstallQuery(String queryName) throws RemoteException;
+
+    public void validateInstallQuery(String queryName, QueryData query) throws RemoteException;
+
+    public void validateUninstallQuery(String queryName, QueryData query) throws RemoteException;
+}