diff --git a/test/freenet/node/NewPacketFormatTest.java b/test/freenet/node/NewPacketFormatTest.java
index 6bf4d34c42..a2ca6d5983 100644
--- a/test/freenet/node/NewPacketFormatTest.java
+++ b/test/freenet/node/NewPacketFormatTest.java
@@ -15,6 +15,7 @@
 import org.junit.Test;
 
 import freenet.crypt.BlockCipher;
+import freenet.crypt.DummyRandomSource;
 import freenet.crypt.ciphers.Rijndael;
 import freenet.io.comm.DMT;
 import freenet.io.comm.FreenetInetAddress;
@@ -33,7 +34,7 @@ public void setUp() {
 	@Test
 	public void testEmptyCreation() throws BlockedTooLongException {
 		NewPacketFormat npf = new NewPacketFormat(null, 0, 0);
-		PeerMessageQueue pmq = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue pmq = new PeerMessageQueue(new DummyRandomSource(1234));
 		SessionKey s = new SessionKey(null, null, null, null, null, null, null, null, new NewPacketFormatKeyContext(0, 0), 1);
 
 		NPFPacket p = npf.createPacket(1400, pmq, s, false);
@@ -44,7 +45,7 @@ public void testEmptyCreation() throws BlockedTooLongException {
 	public void testAckOnlyCreation() throws BlockedTooLongException, InterruptedException {
 		BasePeerNode pn = new NullBasePeerNode();
 		NewPacketFormat npf = new NewPacketFormat(pn, 0, 0);
-		PeerMessageQueue pmq = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue pmq = new PeerMessageQueue(new DummyRandomSource(1234));
 		SessionKey s = new SessionKey(null, null, null, null, null, null, null, null, new NewPacketFormatKeyContext(0, 0), 1);
 
 		NPFPacket p = null;
@@ -65,10 +66,10 @@ public void testAckOnlyCreation() throws BlockedTooLongException, InterruptedExc
 	public void testLostLastAck() throws BlockedTooLongException, InterruptedException {
 		NullBasePeerNode senderNode = new NullBasePeerNode();
 		NewPacketFormat sender = new NewPacketFormat(senderNode, 0, 0);
-		PeerMessageQueue senderQueue = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue senderQueue = new PeerMessageQueue(new DummyRandomSource(1234));
 		NullBasePeerNode receiverNode = new NullBasePeerNode();
 		NewPacketFormat receiver = new NewPacketFormat(receiverNode, 0, 0);
-		PeerMessageQueue receiverQueue = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue receiverQueue = new PeerMessageQueue(new DummyRandomSource(1234));
 		SessionKey senderKey = new SessionKey(null, null, null, null, null, null, null, null, new NewPacketFormatKeyContext(0, 0), 1);
 		senderNode.currentKey = senderKey;
 		SessionKey receiverKey = new SessionKey(null, null, null, null, null, null, null, null, new NewPacketFormatKeyContext(0, 0), 1);
@@ -116,7 +117,7 @@ public void testLostLastAck() throws BlockedTooLongException, InterruptedExcepti
 	public void testOutOfOrderDelivery() throws BlockedTooLongException {
 		NullBasePeerNode senderNode = new NullBasePeerNode();
 		NewPacketFormat sender = new NewPacketFormat(senderNode, 0, 0);
-		PeerMessageQueue senderQueue = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue senderQueue = new PeerMessageQueue(new DummyRandomSource(1234));
 		NullBasePeerNode receiverNode = new NullBasePeerNode();
 		NewPacketFormat receiver = new NewPacketFormat(receiverNode, 0, 0);
 		SessionKey senderKey = new SessionKey(null, null, null, null, null, null, null, null, new NewPacketFormatKeyContext(0, 0), 1);
@@ -142,7 +143,7 @@ public void testOutOfOrderDelivery() throws BlockedTooLongException {
 	public void testReceiveUnknownMessageLength() throws BlockedTooLongException {
 		NullBasePeerNode senderNode = new NullBasePeerNode();
 		NewPacketFormat sender = new NewPacketFormat(senderNode, 0, 0);
-		PeerMessageQueue senderQueue = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue senderQueue = new PeerMessageQueue(new DummyRandomSource(1234));
 		NullBasePeerNode receiverNode = new NullBasePeerNode();
 		NewPacketFormat receiver = new NewPacketFormat(receiverNode, 0, 0);
 		SessionKey senderKey = new SessionKey(null, null, null, null, null, null, null, null, new NewPacketFormatKeyContext(0, 0), 1);
@@ -166,7 +167,7 @@ public void testReceiveUnknownMessageLength() throws BlockedTooLongException {
 	public void testResendAlreadyCompleted() throws BlockedTooLongException, InterruptedException {
 		NullBasePeerNode senderNode = new NullBasePeerNode();
 		NewPacketFormat sender = new NewPacketFormat(senderNode, 0, 0);
-		PeerMessageQueue senderQueue = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue senderQueue = new PeerMessageQueue(new DummyRandomSource(1234));
 		NullBasePeerNode receiverNode = new NullBasePeerNode();
 		NewPacketFormat receiver = new NewPacketFormat(receiverNode, 0, 0);
 		SessionKey senderKey = new SessionKey(null, null, null, null, null, null, null, null, new NewPacketFormatKeyContext(0, 0), 1);
@@ -219,7 +220,7 @@ public SessionKey getCurrentKeyTracker() {
 
 		};
 		NewPacketFormat sender = new NewPacketFormat(senderNode, 0, 0);
-		PeerMessageQueue senderQueue = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue senderQueue = new PeerMessageQueue(new DummyRandomSource(1234));
 		NullBasePeerNode receiverNode = new NullBasePeerNode() {
 			
 			@Override
@@ -284,7 +285,7 @@ public SessionKey getCurrentKeyTracker() {
 
 		};
 		NewPacketFormat sender = new NewPacketFormat(senderNode, 0, 0);
-		PeerMessageQueue senderQueue = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue senderQueue = new PeerMessageQueue(new DummyRandomSource(1234));
 		
 		senderQueue.queueAndEstimateSize(new MessageItem(new byte[128], null, false, null, (short) 0, false, true), 1024);
 
@@ -319,7 +320,7 @@ public void handleMessage(Message msg) {
 
 		};
 		NewPacketFormat sender = new NewPacketFormat(senderNode, 0, 0);
-		PeerMessageQueue senderQueue = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue senderQueue = new PeerMessageQueue(new DummyRandomSource(1234));
 		NullBasePeerNode receiverNode = new NullBasePeerNode() {
 			
 			@Override
@@ -434,7 +435,7 @@ public void testEncryption()
 				receiverNPF =
 				new NewPacketFormat(receiverNode, receiverStartSeq, senderStartSeq);
 
-		PeerMessageQueue senderQueue = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue senderQueue = new PeerMessageQueue(new DummyRandomSource(1234));
 
 		byte[] message = new byte[1024];
 		random.nextBytes(message);
diff --git a/test/freenet/node/PeerMessageQueueTest.java b/test/freenet/node/PeerMessageQueueTest.java
index c434b09f6f..eccbc2701f 100644
--- a/test/freenet/node/PeerMessageQueueTest.java
+++ b/test/freenet/node/PeerMessageQueueTest.java
@@ -7,16 +7,18 @@
 
 import org.junit.Test;
 
+import freenet.crypt.DummyRandomSource;
+
 public class PeerMessageQueueTest {
 	@Test
 	public void testUrgentTimeEmpty() {
-		PeerMessageQueue pmq = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue pmq = new PeerMessageQueue(new DummyRandomSource(1234));
 		assertEquals(Long.MAX_VALUE, pmq.getNextUrgentTime(Long.MAX_VALUE, System.currentTimeMillis()));
 	}
 
 	@Test
 	public void testUrgentTime() {
-		PeerMessageQueue pmq = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue pmq = new PeerMessageQueue(new DummyRandomSource(1234));
 
 		//Constructor might take some time, so grab a range
 		long start = System.currentTimeMillis();
@@ -37,7 +39,7 @@ public void testUrgentTime() {
 	 * it. */
 	@Test
 	public void testUrgentTimeQueuedWrong() {
-		PeerMessageQueue pmq = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue pmq = new PeerMessageQueue(new DummyRandomSource(1234));
 
 		//Constructor might take some time, so grab a range
 		long start = System.currentTimeMillis();
@@ -67,7 +69,7 @@ public void testUrgentTimeQueuedWrong() {
 
 	@Test
 	public void testGrabQueuedMessageItem() {
-		PeerMessageQueue pmq = new PeerMessageQueue(new MersenneTwister(new byte[16]));
+		PeerMessageQueue pmq = new PeerMessageQueue(new DummyRandomSource(1234));
 
 		MessageItem itemUrgent = new MessageItem(new byte[1024], null, false, null, (short) 0, false, false);