Merge r1916129 from trunk (htpasswd docs):

Document SHA-2 support.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1916749 13f79535-47bb-0310-9956-ffa450edef68

Author: notroj

docs/manual/programs/htpasswd.xml

@@ -39,13 +39,6 @@
     stores, though. To use a DBM database see <program>dbmmanage</program> or
     <program>htdbm</program>.</p>
 
-    <p><code>htpasswd</code> encrypts passwords using either bcrypt,
-    a version of MD5 modified for Apache, SHA1, or the system's
-    <code>crypt()</code> routine. Files
-    managed by <code>htpasswd</code> may contain a mixture of different encoding
-    types of passwords; some
-    user records may have bcrypt or MD5-encrypted passwords while others in the
-    same file may have passwords encrypted with <code>crypt()</code>.</p>
     <p><code>htpasswd</code> hashes passwords using either bcrypt, a
     version of MD5 modified for Apache, SHA-1, or the system's
     <code>crypt()</code> routine. SHA-2-based hashes (SHA-256 and
@@ -72,9 +65,12 @@ distribution.</seealso>
     [ -<strong>i</strong> ]
     [ -<strong>m</strong> |
       -<strong>B</strong> |
+      -<strong>2</strong> | 
+      -<strong>5</strong> | 
       -<strong>d</strong> |
       -<strong>s</strong> |
       -<strong>p</strong> ]
+    [ -<strong>r</strong> <var>rounds</var> ]
     [ -<strong>C</strong> <var>cost</var> ]
     [ -<strong>D</strong> ]
     [ -<strong>v</strong> ]  <var>passwdfile</var> <var>username</var></code></p>
@@ -83,9 +79,12 @@ distribution.</seealso>
     [ -<strong>c</strong> ]
     [ -<strong>m</strong> |
       -<strong>B</strong> |
+      -<strong>2</strong> | 
+      -<strong>5</strong> | 
       -<strong>d</strong> |
       -<strong>s</strong> |
       -<strong>p</strong> ]
+    [ -<strong>r</strong> <var>rounds</var> ]
     [ -<strong>C</strong> <var>cost</var> ]
     [ -<strong>D</strong> ]
     [ -<strong>v</strong> ]  <var>passwdfile</var> <var>username</var>
@@ -95,17 +94,23 @@ distribution.</seealso>
     [ -<strong>i</strong> ]
     [ -<strong>m</strong> |
       -<strong>B</strong> |
+      -<strong>2</strong> | 
+      -<strong>5</strong> | 
       -<strong>d</strong> |
       -<strong>s</strong> |
       -<strong>p</strong> ]
+    [ -<strong>r</strong> <var>rounds</var> ]
     [ -<strong>C</strong> <var>cost</var> ] <var>username</var></code></p>
 
     <p><code><strong>htpasswd</strong> -<strong>nb</strong>
     [ -<strong>m</strong> |
-      -<strong>B</strong> |
+      -<strong>B</strong> | 
+      -<strong>2</strong> | 
+      -<strong>5</strong> | 
       -<strong>d</strong> |
       -<strong>s</strong> |
       -<strong>p</strong> ]
+    [ -<strong>r</strong> <var>rounds</var> ]
     [ -<strong>C</strong> <var>cost</var> ] <var>username</var>
     <var>password</var></code></p>
 </section>
@@ -138,6 +143,14 @@ distribution.</seealso>
     <dd>Use MD5 hashing for passwords. This is the default (since version
     2.2.18).</dd>
 
+    <dt><code>-2</code></dt>
+    <dd>Use SHA-256 <code>crypt()</code> based hashes for passwords.  This is
+    supported on most Unix platforms.</dd>
+
+    <dt><code>-5</code></dt>
+    <dd>Use SHA-512 <code>crypt()</code> based hashes for passwords.  This is
+    supported on most Unix platforms.</dd>
+
     <dt><code>-B</code></dt>
     <dd>Use bcrypt hashing for passwords. This is currently considered to
     be very secure.</dd>
@@ -147,6 +160,12 @@ distribution.</seealso>
     hashing). It sets the computing time used for the bcrypt algorithm
     (higher is more secure but slower, default: 5, valid: 4 to 17).</dd>
 
+    <dt><code>-r</code></dt>
+    <dd>This flag is only allowed in combination with <code>-2</code>
+    or <code>-5</code>. It sets the number of hash rounds used for the
+    SHA-2 algorithms (higher is more secure but slower; the default is
+    5,000).</dd>
+
     <dt><code>-d</code></dt>
     <dd>Use <code>crypt()</code> hashing for passwords. This is not
     supported by the <program>httpd</program> server on Windows and
@@ -253,8 +272,14 @@ distribution.</seealso>
     prepending a random salt string, to make dictionary attacks
     against the passwords more difficult.</p>
 
-    <p>The SHA and <code>crypt()</code> formats are insecure by today's
-    standards.</p>
+    <p>The SHA-1 and <code>crypt()</code> formats are insecure by
+    today's standards.</p>
+
+    <p>The SHA-2-based <code>crypt()</code> formats (SHA-256 and
+    SHA-512) are supported on most modern Unix systems, and follow the
+    specification at <a
+    href="https://www.akkadia.org/drepper/SHA-crypt.txt">https://www.akkadia.org/drepper/SHA-crypt.txt</a>.</p>
+    
 </section>
 
 <section id="restrictions"><title>Restrictions</title>