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Editing for the new "Encryption Options" section of the manual.

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This commit is contained in:
Neil Conway 2005-05-25 02:56:15 +00:00
parent 872c1497fc
commit 13b729ca52
1 changed files with 19 additions and 23 deletions
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42
doc/src/sgml/runtime.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.320 2005/05/20 14:53:25 momjian Exp $
$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.321 2005/05/25 02:56:15 neilc Exp $
-->
<chapter Id="runtime">
@ -4965,9 +4965,8 @@ $ <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput
<productname>PostgreSQL</productname> offers encryption at several
levels, and provides flexibility in protecting data from disclosure
due to database server theft, unscrupulous administrators, and
insecure networks. Encryption might also be required by government
regulation, for example, for medical records or financial
transactions.
insecure networks. Encryption might also be required to secure
sensitive data such as medical records or financial transactions.
</para>
<variablelist>
@ -4978,12 +4977,11 @@ $ <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput
<para>
By default, database user passwords are stored as MD5 hashes, so
the administrator can not determine the actual password assigned
the administrator cannot determine the actual password assigned
to the user. If MD5 encryption is used for client authentication,
the unencrypted password is never even temporarily present on the
server because the client MD5 encrypts it before being sent across
the network. MD5 is a one-way encryption --- there is no
decryption algorithm.
server because the client MD5 encrypts it before being sent
across the network.
</para>
</listitem>
</varlistentry>
@ -5025,13 +5023,13 @@ $ <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput
<para>
This mechanism prevents unecrypted data from being read from the
drives if the drives or the entire computer is stolen. This
mechanism does nothing to protect against attacks while the
filesystem is mounted, because when mounted, the operating system
provides a unencrypted view of the data. However, to mount the
filesystem, you need some way for the encryption key to be passed
to the operating system, and sometimes the key is stored somewhere
on the host that mounts the disk.
drives if the drives or the entire computer is stolen. This does
not protect against attacks while the filesystem is mounted,
because when mounted, the operating system provides an unencrypted
view of the data. However, to mount the filesystem, you need some
way for the encryption key to be passed to the operating system,
and sometimes the key is stored somewhere on the host that mounts
the disk.
</para>
</listitem>
</varlistentry>
@ -5048,8 +5046,8 @@ $ <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput
connection was made. It is this double-encrypted value that is
sent over the network to the server. Double-encryption not only
prevents the password from being discovered, it also prevents
another connection from replaying the same double-encryption
value in a later connection.
another connection from using the same encrypted password to
connect to the database server at a later time.
</para>
</listitem>
</varlistentry>
@ -5079,9 +5077,9 @@ $ <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput
It is possible for both the client and server to provide SSL keys
or certificates to each other. It takes some extra configuration
on each side, but this provides stronger verification of identity
than the mere use of passwords. It prevent a computer from
than the mere use of passwords. It prevents a computer from
pretending to be the server just long enough to read the password
send by the client. It also helps prevent 'man in the middle"
send by the client. It also helps prevent "man in the middle"
attacks where a computer between the client and server pretends to
be the server and reads and passes all data between the client and
server.
@ -5094,13 +5092,11 @@ $ <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput
<listitem>
<para>
If the system administrator can not be trusted, it is necessary
If the system administrator cannot be trusted, it is necessary
for the client to encrypt the data; this way, unencrypted data
never appears on the database server. Data is encrypted on the
client before being sent to the server, and database results have
to be decrypted on the client before being used. Peter Wayner's
book, <citation>Translucent Databases</citation>, discusses how to
do this in considerable detail.
to be decrypted on the client before being used.
</para>
</listitem>
</varlistentry>