From 3efde62c446dfe875aa9eb5ff2153ad2ef6f47b5 Mon Sep 17 00:00:00 2001
From: Jeffrey Burdges <burdges@gnunet.org>
Date: Tue, 16 May 2017 16:42:11 +0200
Subject: [PATCH] Try to make this justification stronger and more precise

---
 doc/paper/rom.bib   | 18 ++++++++++++++++++
 doc/paper/taler.tex | 11 ++++++++++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/doc/paper/rom.bib b/doc/paper/rom.bib
index d85b2e891..cd4105218 100644
--- a/doc/paper/rom.bib
+++ b/doc/paper/rom.bib
@@ -72,3 +72,21 @@
 }
 
 
+
+
+@Inbook{Abdalla2000,
+  author="Abdalla, Michel and Bellare, Mihir",
+  editor="Okamoto, Tatsuaki",
+  title="Increasing the Lifetime of a Key: A Comparative Analysis of the Security of Re-keying Techniques",
+  bookTitle="Advances in Cryptology --- ASIACRYPT 2000: 6th International Conference on the Theory and Application of Cryptology and Information Security Kyoto, Japan, December 3--7, 2000 Proceedings",
+  year="2000",
+  publisher="Springer Berlin Heidelberg",
+  address="Berlin, Heidelberg",
+  pages="546--559",
+  isbn="978-3-540-44448-0",
+  doi="10.1007/3-540-44448-3_42",
+  doi_url="http://dx.doi.org/10.1007/3-540-44448-3_42",
+  url="https://link.springer.com/chapter/10.1007/3-540-44448-3_42"
+}
+
+
diff --git a/doc/paper/taler.tex b/doc/paper/taler.tex
index 488f01d06..bdc60e15b 100644
--- a/doc/paper/taler.tex
+++ b/doc/paper/taler.tex
@@ -1335,7 +1335,7 @@ exchange can even invent coins whole cloth.
 We may now remove the encrpytion by appealing to the random oracle
 model~\cite{BR-RandomOracles}.
 
-\begin{lemma}[\cite{??}]
+\begin{lemma}%[\cite{??}]
 Consider a protocol that commits to random data by encrypting it
 using a secret derived from a Diffe-Hellman key exchange.
 In the random oracle model, we may replace this encryption with
@@ -1345,6 +1345,11 @@ functions to the same secret.
 % TODO: Too general probably?
 % TODO: IND-CPA again?
 
+Indeed, we expect doing so to increase practical security as in
+\cite{Abdalla2000}, and adding the random oracle assumption need not
+reduce security if it focuses more attention on the usage of hash
+functions throughout the protocol.
+
 \begin{proof}
 We work with the usual instantiation of the random oracle model as
 returning a random string and placing it into a database for future
@@ -1356,6 +1361,10 @@ that we encrypt in the old encryption based version of Taler.
 Now our random oracle scheme with $R$ gives the same result as our
 scheme that encrypts random data, so the encryption becomes
 superfluous and may be omitted.
+
+We require the security of the original encryption operation reduced
+to the security of the Diffe-Hellman key exchange, which remains a
+requirement of the derived protocol.
 \end{proof}
 
 We may now conclude that Taler remains unlinkable even with the refresh protocol.