htdbm - Manipulate DBM password databases
htdbm -x [ -TDBTYPE ] filename username
(bcrypt encryption). It sets the computing time used for the bcrypt algorithm (higher is more secure but slower, default: 5, valid: 4 to 31).-d
encryption for passwords. The default on all platforms but Windows and Netware. Though possibly supported by htdbm
will support creation on all platforms, the httpd
daemon will only accept plain text passwords on Windows and Netware.-l
is given, the DBM file is created if it does not already exist, or updated if it does exist.username
One should be aware that there are a number of different DBM file formats in existence, and with all likelihood, libraries for more than one format may exist on your system. The three primary examples are SDBM, NDBM, GNU GDBM, and Berkeley/Sleepycat DB 2/3/4. Unfortunately, all these libraries use different file formats, and you must make sure that the file format used by filename is the same format that htdbm
currently has no way of determining what type of DBM file it is looking at. If used against the wrong format, will simply return nothing, or may create a different DBM file with a different name, or at worst, it may corrupt the DBM file if you were attempting to write to it.
program supplied with most Unix systems to see what format a DBM file is in.
returns a zero status ("true") if the username and password have been successfully added or updated in the DBM File. htdbm
if it encounters some problem accessing files, 2
if there was a syntax problem with the command line, 3
if the password was entered interactively and the verification entry didn't match, 4
if its operation was interrupted, 5
if a value is too long (username, filename, password, or final computed record), 6
if the username contains illegal characters (see the Restrictions section), and 7
htdbm /usr/local/etc/apache/.htdbm-users jsmith
Adds or modifies the password for user jsmith
. The user is prompted for the password. If executed on a Windows system, the password will be encrypted using the modified Apache MD5 algorithm; otherwise, the system's crypt()
will do nothing except return an error.
htdbm -c /home/doe/public_html/.htdbm jane
Creates a new file and stores a record in it for user jane
. The user is prompted for the password. If the file exists and cannot be read, or cannot be written, it is not altered and htdbm
will display a message and return an error status.
htdbm -mb /usr/web/.htdbm-all jones Pwd4Steve
Web password files such as those managed by htdbm
should not be within the Web server's URI space -- that is, they should not be fetchable with a browser.
option is discouraged, since when it is used the unencrypted password appears on the command line.
algorithm, note that only the first 8 characters of the password are used to form the password. If the supplied password is longer, the extra characters will be silently discarded.
The SHA encryption format does not use salting: for a given password, there is only one encrypted representation. The crypt()
and MD5 formats permute the representation by prepending a random salt string, to make dictionary attacks against the passwords more difficult.
formats are insecure by today's standards.
characters in length. Longer passwords will be truncated to 255 characters.
is specific to the Apache software; passwords encrypted using it will not be usable with other Web servers.
bytes and may not include the character :
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Apache HTTP Server Version 2.4
htdbm - Manipulate DBM password databases
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htdbm is used to manipulate the DBM format files used to store usernames and password for basic authentication of HTTP users via mod_authn_dbm. See the dbmmanage documentation for more information about these DBM files.
htdbmmod_authn_dbmdbmmanageSee also
httpddbmmanagemod_authn_dbm