diff --git a/domain/src/main/java/ch/dissem/bitmessage/entity/Encrypted.java b/domain/src/main/java/ch/dissem/bitmessage/entity/Encrypted.java
new file mode 100644
index 0000000..b0afcb6
--- /dev/null
+++ b/domain/src/main/java/ch/dissem/bitmessage/entity/Encrypted.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.entity;
+
+import java.io.IOException;
+
+/**
+ * Created by chris on 12.05.15.
+ */
+public interface Encrypted {
+    void encrypt(byte[] publicKey) throws IOException;
+
+    void decrypt(byte[] privateKey) throws IOException;
+}
diff --git a/domain/src/main/java/ch/dissem/bitmessage/entity/payload/V4Pubkey.java b/domain/src/main/java/ch/dissem/bitmessage/entity/payload/V4Pubkey.java
index f4712d2..2a173d0 100644
--- a/domain/src/main/java/ch/dissem/bitmessage/entity/payload/V4Pubkey.java
+++ b/domain/src/main/java/ch/dissem/bitmessage/entity/payload/V4Pubkey.java
@@ -17,8 +17,8 @@
 package ch.dissem.bitmessage.entity.payload;
 
 import ch.dissem.bitmessage.entity.BitmessageAddress;
+import ch.dissem.bitmessage.entity.Encrypted;
 import ch.dissem.bitmessage.utils.Decode;
-import ch.dissem.bitmessage.utils.Security;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -30,7 +30,7 @@ import java.io.OutputStream;
  * use that pubkey. This prevents people from gathering pubkeys sent around the network and using the data from them
  * to create messages to be used in spam or in flooding attacks.
  */
-public class V4Pubkey extends Pubkey {
+public class V4Pubkey extends Pubkey implements Encrypted {
     private long stream;
     private byte[] tag;
     private CryptoBox encrypted;
@@ -54,11 +54,13 @@ public class V4Pubkey extends Pubkey {
                 CryptoBox.read(in, length - 32));
     }
 
-    public void encrypt(byte[] privateKey) throws IOException {
+    @Override
+    public void encrypt(byte[] publicKey) throws IOException {
         if (getSignature() == null) throw new IllegalStateException("Pubkey must be signed before encryption.");
-        this.encrypted = new CryptoBox(decrypted, Security.createPublicKey(privateKey));
+        this.encrypted = new CryptoBox(decrypted, publicKey);
     }
 
+    @Override
     public void decrypt(byte[] privateKey) throws IOException {
         decrypted = V3Pubkey.read(encrypted.decrypt(privateKey), stream);
     }
diff --git a/domain/src/main/java/ch/dissem/bitmessage/utils/Security.java b/domain/src/main/java/ch/dissem/bitmessage/utils/Security.java
index 4d3defa..376b99e 100644
--- a/domain/src/main/java/ch/dissem/bitmessage/utils/Security.java
+++ b/domain/src/main/java/ch/dissem/bitmessage/utils/Security.java
@@ -22,8 +22,6 @@ import ch.dissem.bitmessage.factory.Factory;
 import ch.dissem.bitmessage.ports.ProofOfWorkEngine;
 import org.bouncycastle.asn1.x9.X9ECParameters;
 import org.bouncycastle.crypto.ec.CustomNamedCurves;
-import org.bouncycastle.crypto.params.ECDomainParameters;
-import org.bouncycastle.jce.ECNamedCurveTable;
 import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.bouncycastle.math.ec.ECPoint;
 import org.slf4j.Logger;
@@ -33,7 +31,9 @@ import javax.crypto.Mac;
 import javax.crypto.spec.SecretKeySpec;
 import java.io.IOException;
 import java.math.BigInteger;
-import java.security.*;
+import java.security.GeneralSecurityException;
+import java.security.MessageDigest;
+import java.security.SecureRandom;
 import java.util.Arrays;
 
 /**
@@ -43,14 +43,7 @@ public class Security {
     public static final Logger LOG = LoggerFactory.getLogger(Security.class);
     private static final SecureRandom RANDOM = new SecureRandom();
     private static final BigInteger TWO = BigInteger.valueOf(2);
-    private static final String EC_CURVE_NAME = "secp256k1";
-    private static final X9ECParameters EC_CURVE_PARAMETERS = CustomNamedCurves.getByName(EC_CURVE_NAME);
-    private static final ECDomainParameters EC_DOMAIN_PARAMETERS = new ECDomainParameters(
-            EC_CURVE_PARAMETERS.getCurve(),
-            EC_CURVE_PARAMETERS.getG(),
-            EC_CURVE_PARAMETERS.getN(),
-            EC_CURVE_PARAMETERS.getH()
-    );
+    private static final X9ECParameters EC_CURVE_PARAMETERS = CustomNamedCurves.getByName("secp256k1");
 
     static {
         java.security.Security.addProvider(new BouncyCastleProvider());
@@ -166,7 +159,7 @@ public class Security {
     }
 
     public static ECPoint createPublicKey(byte[] privateKey) {
-        return EC_DOMAIN_PARAMETERS.getG().multiply(keyToBigInt(privateKey)).normalize();
+        return EC_CURVE_PARAMETERS.getG().multiply(keyToBigInt(privateKey)).normalize();
     }
 
     public static BigInteger keyToBigInt(byte[] privateKey) {
@@ -176,11 +169,11 @@ public class Security {
     public static ECPoint keyToPoint(byte[] publicKey) {
         BigInteger x = new BigInteger(1, Arrays.copyOfRange(publicKey, 1, 33));
         BigInteger y = new BigInteger(1, Arrays.copyOfRange(publicKey, 33, 65));
-        return EC_DOMAIN_PARAMETERS.getCurve().createPoint(x, y);
+        return EC_CURVE_PARAMETERS.getCurve().createPoint(x, y);
     }
 
     public static ECPoint createPoint(byte[] x, byte[] y) {
-        return EC_DOMAIN_PARAMETERS.getCurve().createPoint(
+        return EC_CURVE_PARAMETERS.getCurve().createPoint(
                 new BigInteger(1, x),
                 new BigInteger(1, y)
         );