Mark changes, more WIP for viewing keys.

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

protocol/protocol.tex

@@ -329,26 +329,28 @@ is associated with this bit-packing.}
 \daira{Should we instead define $\CoinAddressRand$ to be 254 bits and $\hSig$ to be
 253 bits?}
 
-\subsection{Payment Addresses, Viewing Keys, and Spending Keys}
+\subsection{Payment Addresses\changed{, Viewing Keys,} and Spending Keys}
 
-A \keyTuple $(\PaymentAddress, \ViewingKey, \SpendingKey)$ is generated
+A \keyTuple $(\PaymentAddress, \changed{\ViewingKey,\;} \SpendingKey)$ is generated
 by users who wish to receive payments under this scheme. The parts of
-the \keyTuple are composed from three distinct keypairs, called the
-\authKeypair, \transmitKeypair, and \discloseKeypair keypairs.
+the \keyTuple are composed from \changed{three} distinct keypairs, called the
+\authKeypair, \transmitKeypair \changed{, and \discloseKeypair} keypairs.
 
 \begin{itemize}
   \item The \paymentAddress $\PaymentAddress$ is a pair
         $(\AuthPublic, \TransmitPublic)$, containing the \emph{public}
         components of the \authKeypair and \transmitKeypair keypairs
         respectively.
+\changed{
   \item The \viewingKey $\ViewingKey$ is a pair
         $(\TransmitPrivate, \DisclosePrivate)$, containing the \emph{private}
         components of the \transmitKeypair and \discloseKeypair keypairs
         respectively.
-  \item The \spendingKey $\SpendingKey$ is a triple
-        $(\AuthPrivate, \TransmitPrivate, \DisclosePrivate)$,
+}
+  \item The \spendingKey $\SpendingKey$ is a \changed{triple}
+        $(\AuthPrivate, \TransmitPrivate\changed{, \DisclosePrivate})$,
         containing the \emph{private} components of the \authKeypair,
-        \transmitKeypair, and \discloseKeypair keypairs respectively.
+        \transmitKeypair\changed{, and \discloseKeypair} keypairs respectively.
 \end{itemize}
 
 The following diagram depicts the relations between key components.
@@ -360,19 +362,21 @@ component derived from it.
 \end{center}
 
 Note that a \spendingKey holder can derive
-$(\AuthPublic, \TransmitPublic, \DisclosePublic)$, and a \viewingKey holder
-can derive $(\TransmitPublic, \DisclosePublic)$, even though these components
-are not formally part of the respective keys. Implementations \MAY cache
-these derived public components, provided that they are deleted if the
-corresponding private component is deleted.
+$(\AuthPublic, \TransmitPublic\changed{, \DisclosePublic})$,
+\changed{and a \viewingKey holder can derive $(\TransmitPublic, \DisclosePublic)$,}
+even though these components are not formally part of the respective keys.
+Implementations \MAY cache these derived public components, provided that
+they are deleted if the corresponding private component is deleted.
 
-The composition of \paymentAddresses, \viewingKeys, and \spendingKeys
+The composition of \paymentAddresses\changed{, \viewingKeys,} and \spendingKeys
 is a cryptographic protocol detail that should not normally be
 exposed to users. However, user-visible operations should be provided
 to:
 
 \begin{itemize}
+\changed{
   \item obtain a \viewingKey from a \spendingKey; and
+}
   \item obtain a \paymentAddress from a \spendingKey.
 \end{itemize}
 
@@ -403,10 +407,14 @@ the value and recipient \emph{except} to those who possess these tokens.
 In order to transmit the secret $\Value$, $\CoinAddressRand$, and $\CoinCommitRand$
 (necessary for the recipient to later spend) \changed{and also a \memo} to the
 recipient \emph{without} requiring an out-of-band communication channel, the
-$\transmitKeypair$ public key $\TransmitPublic$ is used to encrypt these
-secrets to form a \coinsCiphertext. The recipient's possession of the associated
+\transmitKeypair public key $\TransmitPublic$ is used to encrypt these
+secrets. The recipient's possession of the associated
 $(\PaymentAddress, \SpendingKey)$ (which contains both $\AuthPublic$ and
 $\TransmitPrivate$) is used to reconstruct the original \coin \changed{ and \memo}.
+\changed{Similarly, to transmit these values to a \viewingKey holder for outgoing
+\PourTransfers, the \discloseKeypair public key $\DisclosePublic$ is used to
+encrypt the same secrets.}
+The encryptions are combined to form a \coinsCiphertext.
 
 \changed{
 The encryption algorithm is defined in terms of $\CryptoBox$ (i.e.