From c9e090818272174cf38de4d498d4e1bd6c7f4dd5 Mon Sep 17 00:00:00 2001
From: Peter Palfrader <peter@palfrader.org>
Date: Mon, 27 Oct 2003 21:53:02 +0000
Subject: Further work on SURBs.  Decoding and further tests still required.

---
 src/org/noreply/fancydress/type3/SURB.java              |  8 +++++---
 .../fancydress/type3/routing/RoutingDestination.java    | 17 +++++++++++++++++
 .../noreply/fancydress/type3/routing/RoutingSMTP.java   |  5 ++++-
 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/src/org/noreply/fancydress/type3/SURB.java b/src/org/noreply/fancydress/type3/SURB.java
index 4ef8948..6733909 100644
--- a/src/org/noreply/fancydress/type3/SURB.java
+++ b/src/org/noreply/fancydress/type3/SURB.java
@@ -25,7 +25,7 @@ public class SURB extends SingleLeg {
 			validateHash = CryptoPrimitives.hash(seed, secret, validate);
 		} while (validateHash[validateHash.length-1] == 0);
 
-		byte[] key = Util.slice(CryptoPrimitives.hash(seed, secret, Util.toOctets("Generate")), 0,CryptoPrimitives.KEY_LEN);
+		byte[] key = Util.slice(CryptoPrimitives.hash(seed, secret, Util.toOctets("Generate")), 0, CryptoPrimitives.KEY_LEN);
 		byte[] stream = CryptoPrimitives.prng(key, CryptoPrimitives.KEY_LEN*(hops.length + 1));
 
 		sharedSecret = Util.slice(stream, CryptoPrimitives.KEY_LEN*hops.length, CryptoPrimitives.KEY_LEN);
@@ -33,6 +33,7 @@ public class SURB extends SingleLeg {
 		for (int i=0; i<hops.length; i++)
 			sharedKeys[i] = Util.slice(stream, (hops.length-i-1)*CryptoPrimitives.KEY_LEN, CryptoPrimitives.KEY_LEN);
 
+		address.setDecodingHandle(seed);
 		makeLeg(hops, sharedKeys, address);
 	};
 
@@ -50,9 +51,10 @@ public class SURB extends SingleLeg {
 	public String export() {
 		byte[] beginMarker = Util.toOctets("SURB");
 		int useBy = 1068595200; //FIXME // Y2k36
-		byte[] routingInformation = getRoute().getRoutingInformation();
+		RoutingForward route = getRoute().asSwap();
+		byte[] routingInformation = route.getRoutingInformation();
 		int routingSize = routingInformation.length;
-		int routingType = getRoute().getRoutingType();
+		int routingType = route.getRoutingType();
 
 		byte[] result = new byte[4+2+4+SINGLE_HEADER_LEN+2+2+CryptoPrimitives.KEY_LEN+routingSize];
 
diff --git a/src/org/noreply/fancydress/type3/routing/RoutingDestination.java b/src/org/noreply/fancydress/type3/routing/RoutingDestination.java
index 38a0342..500ebc5 100644
--- a/src/org/noreply/fancydress/type3/routing/RoutingDestination.java
+++ b/src/org/noreply/fancydress/type3/routing/RoutingDestination.java
@@ -15,6 +15,11 @@ public abstract class RoutingDestination extends Routing {
 	 */
 	public static final int DECODINGHANDLE_LEN = 20;
 
+	/**
+	 * A decoding handle as is used in SURBS or forward encrypted messages.
+	 */
+	protected byte[] decodingHandle;
+
 	/**
 	 * Default constructor.
 	 *
@@ -22,6 +27,18 @@ public abstract class RoutingDestination extends Routing {
 	 */
 	protected RoutingDestination(int type) {
 		super (type);
+		decodingHandle = null;
+	}
+
+	/**
+	 * Set a decoding handle as is used in SURBS or forward encrypted messages.
+	 *
+	 * @param decodingHandle decoding handle
+	 */
+	public void setDecodingHandle(byte[] decodingHandle) {
+		if (decodingHandle.length != DECODINGHANDLE_LEN)
+			throw new Error("Decoding handle is not DECODINGHANDLE_LEN bytes long.");
+		this.decodingHandle = decodingHandle;
 	}
 }
 
diff --git a/src/org/noreply/fancydress/type3/routing/RoutingSMTP.java b/src/org/noreply/fancydress/type3/routing/RoutingSMTP.java
index 77df42f..b969841 100644
--- a/src/org/noreply/fancydress/type3/routing/RoutingSMTP.java
+++ b/src/org/noreply/fancydress/type3/routing/RoutingSMTP.java
@@ -50,7 +50,10 @@ public class RoutingSMTP extends RoutingDestination {
 		byte[] result = new byte[length];
 		int pos = 0;
 
-		System.arraycopy(CryptoPrimitives.rand(DECODINGHANDLE_LEN), 0, result, pos, DECODINGHANDLE_LEN);
+		if (decodingHandle == null)
+			System.arraycopy(CryptoPrimitives.rand(DECODINGHANDLE_LEN), 0, result, pos, DECODINGHANDLE_LEN);
+		else
+			System.err.println("Using set decoding handle for "+mailbox);
 		pos += DECODINGHANDLE_LEN;
 		System.arraycopy(Util.toOctets(mailbox), 0, result, pos, mailbox.length());
 		pos += mailbox.length();
-- 
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