fixed typos, added limitations to dovecot and postfix sections

diff --git a/src/ECC.tex b/src/ECC.tex
index 379aca6..ac25c17 100644 (file)
--- a/src/ECC.tex
+++ b/src/ECC.tex
@@ -25,7 +25,7 @@ there has been a lot of discussion regarding these parameters and their
 potential subversion. A part of the discussion involved recommended sets 
 of curves and curve points chosen by different standardization bodies such 
 as the National Institute of Standards and Technology (NIST) 
 potential subversion. A part of the discussion involved recommended sets 
 of curves and curve points chosen by different standardization bodies such 
 as the National Institute of Standards and Technology (NIST) 

-\footnote{\url{http://www.nist.gov}}. Wich were later widley implemented 
+\footnote{\url{http://www.nist.gov}}. Which were later widely implemented 

 in most common crypto libraries. Those parameters came under question 
 repeatedly from cryptographers
 \footnote{\url{http://cr.yp.to/talks/2013.09.16/slides-djb-20130916-a4.pdf}}
 in most common crypto libraries. Those parameters came under question 
 repeatedly from cryptographers
 \footnote{\url{http://cr.yp.to/talks/2013.09.16/slides-djb-20130916-a4.pdf}}

diff --git a/src/cipher_suites.tex b/src/cipher_suites.tex
index 63634c7..447f178 100644 (file)
--- a/src/cipher_suites.tex
+++ b/src/cipher_suites.tex
@@ -2,22 +2,22 @@
 
 Cipher suites are a combination of algorithms to provide for 
 Confidentiality, Integrity and Authenticity
 
 Cipher suites are a combination of algorithms to provide for 
 Confidentiality, Integrity and Authenticity

-\footnote{url{http://en.wikipedia.org/wiki/Information\_security}} of 
+\footnote{\url{http://en.wikipedia.org/wiki/Information\_security}} of 

 communication. For example: sending encrypted data over the wire does not 
 ensure that the data can not be modified (message integrity), similarly
 communication. For example: sending encrypted data over the wire does not 
 ensure that the data can not be modified (message integrity), similarly

-encrypted data can be sent from an advesary. It is therefore paramount to
-proof that data has been sent from the desired source (message authenticity).
+encrypted data can be sent from an adversary. It is therefore paramount to
+prove that data has been sent from the desired source (message authenticity).

 This concept is known as authenticated encryption
 This concept is known as authenticated encryption

-\footnote{url{http://en.wikipedia.org/wiki/Authenticated\_encryption}}
-\footnote{url{http://www.cs.jhu.edu/~astubble/dss/ae.pdf}}.
+\footnote{\url{http://en.wikipedia.org/wiki/Authenticated\_encryption}}
+\footnote{\url{http://www.cs.jhu.edu/~astubble/dss/ae.pdf}}.

 
 \subsection{Forward Secrecy}
 Forward Secrecy or Perfect Forward Secrecy is a property of a cipher suite 
 that ensures confidentiality even if the server key has been compromised.
 
 \subsection{Forward Secrecy}
 Forward Secrecy or Perfect Forward Secrecy is a property of a cipher suite 
 that ensures confidentiality even if the server key has been compromised.

-Thus if traffic has been recorded it can not be decrypted even if an advesary
+Thus if traffic has been recorded it can not be decrypted even if an adversary

 has got hold of the decryption key
 has got hold of the decryption key

-\footnote{url{http://en.wikipedia.org/wiki/Forward\_secrecy}}
-\footnote{urk{https://www.eff.org/deeplinks/2013/08/pushing-perfect-forward-secrecy-important-web-privacy-protection}}. 
+\footnote{\url{http://en.wikipedia.org/wiki/Forward\_secrecy}}
+\footnote{\url{https://www.eff.org/deeplinks/2013/08/pushing-perfect-forward-secrecy-important-web-privacy-protection}}. 

 
 \subsection{Recommended cipher suites}
 
 
 \subsection{Recommended cipher suites}
 


@@ -29,7 +29,7 @@ tool to test out different settings. The authors used ssllabs.com to arrive at
 a set of cipher suites which we will recommend throught this document.
 \textbf{Caution: these settings can only represent a subjective choice of the
 authors at the time of this writing. It might be a wise choice to select your
 a set of cipher suites which we will recommend throught this document.
 \textbf{Caution: these settings can only represent a subjective choice of the
 authors at the time of this writing. It might be a wise choice to select your

-own ciper suites based on the instructions in section
+own cipher suites based on the instructions in section

 \ref{section:ChosingYourOwnCipherSuites}}.
 
 
 \ref{section:ChosingYourOwnCipherSuites}}.
 
 


@@ -79,7 +79,7 @@ ID        & OpenSSL name                & Version & KeyEx & Auth & Cipher & Hash
 
 \textbf{Compatibility}
 
 
 \textbf{Compatibility}
 

-Only clients which support TLS1.2 are covered by this cipher suites (Chrome 30,
+Only clients which support TLS1.2 are covered by these cipher suites (Chrome 30,

 Win 7 and Win 8.1 crypto stack, Opera 17, OpenSSL $\ge$ 1.0.1e, Safari 6 / iOS
 6.0.1, Safari 7 / OS X 10.9).
 
 Win 7 and Win 8.1 crypto stack, Opera 17, OpenSSL $\ge$ 1.0.1e, Safari 6 / iOS
 6.0.1, Safari 7 / OS X 10.9).
 


@@ -129,22 +129,24 @@ ID        & OpenSSL name                      & Version & KeyEx & Auth & Cipher & Hash \\ \hlin
 
 \textbf{Compatibility}
 
 
 \textbf{Compatibility}
 

-Note that this cipher suites will not work with anything using Windows XP's
+Note that these cipher suites will not work with anything using Windows XP's

 crypto stack (IE, Outlook), Java 6, Java 7 and Android 2.3. Java 7 could be
 made compatible by installing the "Java Cryptography Extension (JCE) Unlimited
 crypto stack (IE, Outlook), Java 6, Java 7 and Android 2.3. Java 7 could be
 made compatible by installing the "Java Cryptography Extension (JCE) Unlimited

-Strength Jurisdiction Policy Files" (JCE). We could not verify yet if
-installing JCE also fixes the Java 7 DH-parameter length limitation (1024 bit). 
+Strength Jurisdiction Policy Files"
+(JCE) \footnote{\url{http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html}}.
+We could not verify yet if installing JCE also fixes the Java 7
+DH-parameter length limitation (1024 bit). 

 
 \textbf{Explanation}
 
 For a detailed explanation of the cipher suites chosen, please see
 \ref{section:ChosingYourOwnCipherSuites}. In short, finding the perfect cipher
 string is impossible and must be a tradeoff. On the one hand
 
 \textbf{Explanation}
 
 For a detailed explanation of the cipher suites chosen, please see
 \ref{section:ChosingYourOwnCipherSuites}. In short, finding the perfect cipher
 string is impossible and must be a tradeoff. On the one hand

-there are mandatory and optional ciphers defined in a few RFCs on the other hand
+there are mandatory and optional ciphers defined in a few RFCs, on the other hand

 there are clients and servers only implementing subsets of the specification.
 
 Straight forward, we wanted strong ciphers, forward secrecy
 there are clients and servers only implementing subsets of the specification.
 
 Straight forward, we wanted strong ciphers, forward secrecy

-\footnote{url{http://nmav.gnutls.org/2011/12/price-to-pay-for-perfect-forward.html}}
+\footnote{\url{http://nmav.gnutls.org/2011/12/price-to-pay-for-perfect-forward.html}}

 and the most clients we could get while still having a cipher string that can be
 used on older servers too (think OpenSSL 0.9.8). This cipher string is meant to be used
 by copy and paste and needs to just work.
 and the most clients we could get while still having a cipher string that can be
 used on older servers too (think OpenSSL 0.9.8). This cipher string is meant to be used
 by copy and paste and needs to just work.


@@ -239,7 +241,7 @@ Following Ivan Ristic's adivce we arrived at a categorisation of cipher suites.
 \end{tabular}
 \end{center}
 
 \end{tabular}
 \end{center}
 

-A remark on the ``consider'' section: the BSI (Federal office for information security, Germany) recommends in its technical report TR-02102-2\footnote{\url{https://www.bsi.bund.de/SharedDocs/Downloads/DE/BSI/Publikationen/TechnischeRichtlinien/TR02102/BSI-TR-02102-2_pdf.html}} to \textbf{avoid} non-ephemeral\footnote{ephemeral keys are session keys which are destroyed upon termination of the encrypted session. In TLS/SSL, they are realized by the DHE cipher suites. } keys for any communication which might contain personal or sensitive data. In this document, we follow BSI's advice and therefore only keep cipher suites containing (EC)DH\textbf{E} (ephemeral) variants. System administrators, who can not use forward secrecy can still use the cipher suites in the ``consider'' section. We however, do not recommend them in this document.
+A remark on the ``consider'' section: the BSI (Federal office for information security, Germany) recommends in its technical report TR-02102-2\footnote{\url{https://www.bsi.bund.de/SharedDocs/Downloads/DE/BSI/Publikationen/TechnischeRichtlinien/TR02102/BSI-TR-02102-2_pdf.html}} to \textbf{avoid} non-ephemeral\footnote{Ephemeral keys are session keys which are destroyed upon termination of the encrypted session. In TLS/SSL, they are realized by the DHE cipher suites. } keys for any communication which might contain personal or sensitive data. In this document, we follow BSI's advice and therefore only keep cipher suites containing (EC)DH\textbf{E} (ephemeral) variants. System administrators, who can not use forward secrecy can still use the cipher suites in the ``consider'' section. We however, do not recommend them in this document.

 
 %% NOTE: s/forward secrecy/perfect forward secrecy???
 
 
 %% NOTE: s/forward secrecy/perfect forward secrecy???
 

diff --git a/src/practical_settings.tex b/src/practical_settings.tex
index e2052d1..6e7ad70 100644 (file)
--- a/src/practical_settings.tex
+++ b/src/practical_settings.tex
@@ -192,6 +192,9 @@ Dovecot 2.2:
 
 Dovecot 2.1: Almost as good as dovecot 2.2. Does not support ssl\_prefer\_server\_ciphers
 
 
 Dovecot 2.1: Almost as good as dovecot 2.2. Does not support ssl\_prefer\_server\_ciphers
 

+\paragraph*{Limitations}\mbox{}\\
+
+Dovecot currently does not support disabling TLS compression.

 
 \subsubsection{cyrus-imapd (based on 2.4.17)}
 
 
 \subsubsection{cyrus-imapd (based on 2.4.17)}
 


@@ -316,6 +319,15 @@ $ zegrep "TLS connection established from.*with cipher" /var/log/mail.log | \
 
 Source: \url{http://www.postfix.org/TLS_README.html}
 
 
 Source: \url{http://www.postfix.org/TLS_README.html}
 

+\paragraph*{Limitations}\mbox{}\\
+
+tls\_ssl\_options is supported from Postfix 2.11 onwards. You can
+leave the statement in the configuration for older versions, it will
+be ignored.
+
+tls\_preempt\_cipherlist is supported from Postfix 2.8 onwards. Again,
+you can leave the statement in for older versions.
+

 \subsubsection{Exim (based on 4.82)}
 
 It is highly recommended to read
 \subsubsection{Exim (based on 4.82)}
 
 It is highly recommended to read