1 files changed, 78 insertions, 0 deletions
diff --git a/src/org/noreply/fancydress/type3/Packet.java b/src/org/noreply/fancydress/type3/Packet.java
new file mode 100644
index 0000000..3d76cbe
--- /dev/null
+++ b/src/org/noreply/fancydress/type3/Packet.java
@@ -0,0 +1,78 @@
+package org.noreply.fancydress.type3;
+
+import org.noreply.fancydress.misc.Util;
+import org.noreply.fancydress.type3.routing.*;
+import org.noreply.fancydress.crypto.*;
+import org.noreply.fancydress.status.*;
+import java.util.*;
+
+public class Packet {
+
+	private byte[] packet;
+	private Routing thisRoute;
+
+	public Packet(
+		Path path,
+		RoutingDestination address,
+		Payload payload)
+	throws Mix3BadArgumentsChainTooLongException
+	{
+		ForwardLeg leg2 = new ForwardLeg(path.getSecondHalf(), address);
+		if (!(leg2.getRoute() instanceof RoutingForward))
+			throw new Error("Routing Type of second leg is not a forward type.");
+		ForwardLeg leg1 = new ForwardLeg(path.getFirstHalf(), ((RoutingForward)leg2.getRoute()).asSwap());
+		makePacket(leg1, leg2, payload);
+	}
+
+	public Packet(
+		HalfPath path,
+		SURB surb,
+		Payload payload)
+	throws Mix3BadArgumentsChainTooLongException
+	{
+		ForwardLeg leg1 = new ForwardLeg(path, surb.getRoute());
+		makePacket(leg1, surb, payload);
+	}
+
+	public static boolean isPacketVersionSupported(String s) {
+		return s.equals(SingleLeg.MAJOR_VERSION + "." + SingleLeg.MINOR_VERSION);
+	}
+
+	private void makePacket(ForwardLeg leg1, SingleLeg leg2, Payload payload) {
+		byte p[] = payload.asOctets();
+		byte h1[] = leg1.asOctets();
+		byte h2[] = leg2.asOctets();
+
+		// Phase 1
+		if (leg2 instanceof SURB) {
+			byte[] k = ((SURB) leg2).getEncryptionKey();
+			p = CryptoPrimitives.sprpDecrypt(k, "PAYLOAD ENCRYPT", p);
+		} else {
+			byte[][] sk = ((ForwardLeg) leg2).getSharedKeys();
+			for (int i=sk.length-1; i>=0; i--)
+				p = CryptoPrimitives.sprpEncrypt(sk[i], "PAYLOAD ENCRYPT", p);
+		}
+
+		// Phase 2
+		h2 = CryptoPrimitives.sprpEncrypt(CryptoPrimitives.hash(p), "HIDE HEADER", h2);
+		p = CryptoPrimitives.sprpEncrypt(CryptoPrimitives.hash(h2), "HIDE PAYLOAD", p);
+
+		byte[][] sk = leg1.getSharedKeys();
+		for (int i=sk.length-1; i>=0; i--) {
+			h2 = CryptoPrimitives.sprpEncrypt(sk[i], "HEADER ENCRYPT", h2);
+			p = CryptoPrimitives.sprpEncrypt(sk[i], "PAYLOAD ENCRYPT", p);
+		}
+
+		packet = Util.concat(Util.concat(h1,h2),p);
+		thisRoute = leg1.getRoute();
+	}
+
+	public Routing getRoute() {
+		return thisRoute;
+	}
+
+	public byte[] asOctets() {
+		return packet;
+	}
+}
+