[freehaven-cvs] Protocol section fixes.

[rabbi@seul.org]

Update of /home2/freehaven/cvsroot/doc/pynchon-gate
In directory moria.mit.edu:/tmp/cvs-serv18788

Modified Files:
	pynchon.tex 
Log Message:
Protocol section fixes.


Index: pynchon.tex
===================================================================
RCS file: /home2/freehaven/cvsroot/doc/pynchon-gate/pynchon.tex,v
retrieving revision 1.21
retrieving revision 1.22
diff -u -d -r1.21 -r1.22
--- pynchon.tex	16 Sep 2004 18:50:03 -0000	1.21
+++ pynchon.tex	16 Sep 2004 19:15:44 -0000	1.22
@@ -336,6 +336,8 @@
   SUBKEY(j+1,i) = H(SUBKEY(j,i) | "NEXT SECRET") 
   SUBKEY(0,i) = H(S[i] | "NEXT SECRET")
 
+%XXXX Turn me into latex!
+
 We use a separate chain of keys for each cycle so that it is easier for a
 user to resynchronize after missing a few cycles.
    
@@ -347,6 +349,7 @@
 in the clear, and the messages for the nym user are encrypted and MAC'd
 using that iteration of the dynamic key.
 
+%XXXX Turn me into latex!
       UserID[i] = H(S[i] | "USER ID")
 
 Dynamic key rotation allows us to achieve forward secrecy. Without dynamic
@@ -372,23 +375,23 @@
 Messages for nym owners are passed to the collator component.\footnote{The
 collator component typically resides on the same physical server as the
 nym server component.} The collator component organizes all previously
-unretrieved messages into a tree structure, with messages sorted by
-publicly viewable identifiers derived from the dynamic shared secrets.
-Nodes in the tree are organized into fixed-size \emph{buckets}. The
-collator then publishes metadata about the tree as a whole in a widely
-available manner.
+unretrieved messages into a three-level tree structure, with messages
+sorted by publicly viewable identifiers derived from the dynamic shared
+secrets. Nodes in the tree are organized into fixed-size \emph{buckets}.
+The collator then publishes metadata (in the form of a signed meta-index)
+about the tree as a whole in a widely available manner.
 
 % XXXX Overflow? Pending messages? ACK and ERR messages? Do we discuss
 % this here, or later, after explaining the system?
 
 \subsection{The Distributor Nodes}
 
-The entire set of buckets is retrieved from the collator by
-multiple \emph{distributor nodes}.\footnote{This should be accomplished by
-using a bandwidth-sparing protocol such as BitTorrent~\cite{bittorrent}.}
-Distributors append to each bucket the path from that bucket to the hash
-tree root. These distributors communicate to the client application using
-the \emph{Pynchon Gate PIR Protocol}.
+The entire set of buckets is retrieved from the collator by multiple
+independently-operated \emph{distributor nodes}.\footnote{This should be
+accomplished by using a bandwidth-sparing protocol such as
+BitTorrent~\cite{bittorrent}.} Distributors append to each bucket the path
+from that bucket to the hash tree root. These distributors communicate to
+the client application using the \emph{Pynchon Gate PIR Protocol}.
 
 \subsection{The Pynchon Gate Client}
 \label{subsec:client-design}
@@ -401,14 +404,14 @@
 sends a random-looking bit field to the distributor. This bit field has a
 length equal to the number of buckets. The distributor performs a linear
 scan across all buckets, and XORs the buckets whose positions have a
-corresponding 1 in the bit field. The result of this xor is then returned
+corresponding 1 in the bit field. The result of this XOR is then returned
 to the client.\footnote{As an optimization, a client may send a seed to a
 stream cipher instead of the full bit field. The distributor will use the
 stream cipher as a pseudo-random number generator to generate the full bit
 field. This reduces the size of the request from linear on the number of
 buckets to fixed~\cite{prng-back}.}
 
-For the final distributor, the client takes the xor of all of the other
+For the final distributor, the client takes the XOR of all of the other
 bit fields that it sent\footnote{Stream cipher output generated by the
 seeds it sent could also be used.} and flips a single bit corresponding to
 the bucket to be retrieved.\footnote{The bandwidth conservation

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