Re: Using Encryption Patch to Docs

I have reworded some of the encryption sections in this patch and
applied the changes:

http://candle.pha.pa.us/main/writings/pgsql/sgml/encryption-approaches.html

I moved the section up a few sections, changes the markup a little, and
removed the encryption FAQ item now that we have a clearer encryption
section.

---------------------------------------------------------------------------

pgman wrote:
>
> Patch applied. Thanks. Your documentation changes can be viewed in
> five minutes using links on the developer's page,
> http://www.postgresql.org/developer/testing.
>
>
> ---------------------------------------------------------------------------
>
>
> Christopher Browne wrote:
> > ? out
> > Index: runtime.sgml
> > ===================================================================
> > RCS file: /projects/cvsroot/pgsql/doc/src/sgml/runtime.sgml,v
> > retrieving revision 1.315
> > diff -u -r1.315 runtime.sgml
> > --- runtime.sgml 23 Apr 2005 03:27:40 -0000 1.315
> > +++ runtime.sgml 29 Apr 2005 16:43:22 -0000
> > @@ -5109,6 +5109,132 @@
> >
> > </sect1>
> >
> > + <sect1 id="encryption-approaches">
> > + <title>Use of Encryption in <productname>PostgreSQL</productname></title>
> > + <indexterm zone="encryption-approaches">
> > + <primary>encryption</primary>
> > + </indexterm>
> > +
> > + <para> There is increasing interest in having verifiable mechanisms
> > + to maintain the privacy of data in databases. In the United
> > + States, legislation called <acronym>HIPAA</acronym> (Health
> > + Insurance Portability and Accountability Act) requires that
> > + personal health information is handled securely. The European
> > + Union has similarly been developing directives as to how personal
> > + data is to be managed there.</para>
> > +
> > + <para> Questions frequently come up as to what functionality
> > + <productname>PostgreSQL</productname> offers with regard to
> > + supporting the use of data encryption. It uses and provides use of
> > + encryption tools in several ways that may be useful to provide
> > + protection against certain classes of attacks.</para>
> > +
> > + <itemizedlist>
> > +
> > + <listitem><para> Passwords stored in MD5 form </para>
> > +
> > + <para> Passwords are normally not stored in
> > + <quote>plaintext</quote> form in the database; they are hashed
> > + using the built-in MD5 function, and <emphasis>that</emphasis> is
> > + what is stored in the database. </para>
> > +
> > +<programlisting>
> > +sample=# alter user foo password 'some dumb value';
> > +ALTER USER
> > +sample=# select usename, passwd from pg_shadow where usename = 'foo';
> > + usename | passwd
> > +---------+-------------------------------------
> > + foo | md5740daa4aaa084d85eb97648084a43bbb
> > +(1 row)
> > +</programlisting>
> > +
> > +</listitem>
> > +
> > + <listitem><para> Connections protected using SSL</para>
> > +
> > + <para> There are various options to control how mandatory it is
> > + to use SSL to protect data connections. At the most
> > + <quote>paranoid</quote> end of the spectrum, you can configure
> > + <filename>pg_hba.conf</filename> to have the database reject
> > + connections that do <emphasis>not</emphasis> come in via
> > + SSL.</para>
> > +
> > + <para> The use of SSL, alone, is useful for protecting
> > + communications against interception. It may not be necessary
> > + for connections that take place across a carefully controlled
> > + network; if connections are coming in from less controlled
> > + sources, its use is highly recommended.</para></listitem>
> > +
> > + <listitem><para> Connections authenticated using SSL</para>
> > +
> > + <para> It is possible for both the client and server to provide
> > + to one another SSL keys or certificates. It takes some extra
> > + configuration on each side where these are used, but this likely
> > + provides stronger verification of identity than the mere use of a
> > + text password. </para></listitem>
> > +
> > + <listitem><para> Using OS level encryption for entire database
> > + partitions</para>
> > +
> > + <para> On Linux, encryption can be layered on top of a filesystem
> > + mount using what is called a <quote>loopback device;</quote> this
> > + permits having a whole filesystem partition be encrypted on disk,
> > + decrypted by the operating system. On FreeBSD, the equivalent
> > + facility is called GEOM Based Disk Encryption, or
> > + <acronym>gbde</acronym>.</para>
> > +
> > + <para> This mechanism may be expected to be useful for protecting
> > + against the threat that someone might pull disk drives out and
> > + try to install them somewhere else to draw data off of them.
> > + </para>
> > +
> > + <para> In contrast, this mechanism does nothing to protect
> > + against attacks when the filesystem is mounted, because when
> > + mounted, the OS provides a <quote>view</quote> of the filesystem
> > + accessible in plain text form. Furthermore, you need some way
> > + for the encryption key to be passed to the operating system in
> > + order to mount the filesystems, which encourages having the key
> > + accessible somewhere on the host that mounts the disk.
> > + </para></listitem>
> > +
> > + <listitem><para> Using the contrib function library
> > + <function>pgcrypto</function> so the database engine manages
> > + encryption of certain fields.</para>
> > +
> > + <para>If much of the data can be in plain text form, and only a
> > + subset is particularly sensitive, this mechanism supports
> > + treating them differently. The encrypted data is only ever
> > + presented in <quote>unencrypted</quote> form while it is being
> > + communicated between client and server, and the use of an SSL
> > + layer of <quote>superencryption</quote> alleviates that
> > + problem.</para>
> > +
> > + <para> Unfortunately, in this approach, the encryption keys need
> > + to be present on the server, even if only for a moment, which
> > + presents the possibility of them being intercepted by someone
> > + with access to the database server. As a result, this mechanism
> > + is not suitable for storage of data that is too sensitive for
> > + system administrators to have access to it. </para></listitem>
> > +
> > + <listitem><para> Using cryptographic tools on the client </para>
> > +
> > + <para> If it is not safe to trust the system administrators at
> > + least somewhat, you may find it necessary to encrypt data at the
> > + client level such that unencrypted data never appears on the
> > + database server. This sort of <quote>paranoia</quote> is quite
> > + appropriate for applications where it would be damaging for data
> > + to be seen by inappropriate readers that might generally be
> > + considered trustworthy, as can be the case with
> > + medical and legal records.</para>
> > +
> > + <para> Peter Wayner's book, <citation>Translucent
> > + Databases</citation>, discusses how to do this in considerable
> > + detail.</para></listitem>
> > +
> > + </itemizedlist>
> > +
> > + </sect1>
> > +
> > </chapter>
> >
> > <!-- Keep this comment at the end of the file
> >
>
> --
> Bruce Momjian | http://candle.pha.pa.us
> pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
> + If your life is a hard drive, | 13 Roberts Road
> + Christ can be your backup. | Newtown Square, Pennsylvania 19073

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073