htpasswd - Manage user files for basic authentication
htpasswd [ -
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2 | -
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rounds ] [ -
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D ] [ -
v ]
passwdfile username
htpasswd -
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passwdfile username password
htpasswd -
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username
htpasswd -
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username password
htpasswd is used to create and update the flat-files used to store
usernames and password for basic authentication of HTTP users. If
htpasswd cannot access a file, such as not being able to write to the
output file or not being able to read the file in order to update it, it
returns an error status and makes no changes.
Resources available from the Apache HTTP server can be restricted to just the
users listed in the files created by
htpasswd. This program can only
manage usernames and passwords stored in a flat-file. It can hash and display
password information for use in other types of data stores, though. To use a
DBM database see dbmmanage or htdbm.
htpasswd hashes passwords using either bcrypt, a version of MD5 modified
for Apache, SHA-1, or the system's
crypt() routine. SHA-2-based hashes
(SHA-256 and SHA-512) are supported for
crypt(). Files managed by
htpasswd may contain a mixture of different encoding types of
passwords; some user records may have bcrypt or MD5-hashed passwords while
others in the same file may have passwords hashed with
crypt().
This manual page only lists the command line arguments. For details of the
directives necessary to configure user authentication in httpd see the Apache
manual, which is part of the Apache distribution or can be found at
http://httpd.apache.org/.
- -b
- Use batch mode; i.e., get the password from the
command line rather than prompting for it. This option should be used with
extreme care, since the password is clearly visible on the command
line. For script use see the -i option. Available in 2.4.4 and
later.
- -i
- Read the password from stdin without verification (for
script usage).
- -c
- Create the passwdfile. If passwdfile already
exists, it is rewritten and truncated. This option cannot be combined with
the -n option.
- -n
- Display the results on standard output rather than updating
a file. This is useful for generating password records acceptable to
Apache for inclusion in non-text data stores. This option changes the
syntax of the command line, since the passwdfile argument (usually
the first one) is omitted. It cannot be combined with the -c
option.
- -m
- Use MD5 hashing for passwords. This is the default (since
version 2.2.18).
- -2
- Use SHA-256 crypt() based hashes for passwords. This
is supported on most Unix platforms.
- -5
- Use SHA-512 crypt() based hashes for passwords. This
is supported on most Unix platforms.
- -B
- Use bcrypt hashing for passwords. This is currently
considered to be very secure.
- -C
- This flag is only allowed in combination with -B
(bcrypt hashing). It sets the computing time used for the bcrypt algorithm
(higher is more secure but slower, default: 5, valid: 4 to 17).
- -r
- This flag is only allowed in combination with -2 or
-5. It sets the number of hash rounds used for the SHA-2 algorithms
(higher is more secure but slower; the default is 5,000).
- -d
- Use crypt() hashing for passwords. This is not
supported by the httpd server on Windows and Netware. This algorithm
limits the password length to 8 characters. This algorithm is
insecure by today's standards. It used to be the default algorithm
until version 2.2.17.
- -s
- Use SHA-1 (160-bit) hashing for passwords. Facilitates
migration from/to Netscape servers using the LDAP Directory Interchange
Format (ldif). This algorithm is insecure by today's
standards.
- -p
- Use plaintext passwords. Though htpasswd will
support creation on all platforms, the httpd daemon will only accept plain
text passwords on Windows and Netware.
- -D
- Delete user. If the username exists in the specified
htpasswd file, it will be deleted.
- -v
- Verify password. Verify that the given password matches the
password of the user stored in the specified htpasswd file. Available in
2.4.5 and later.
-
passwdfile
- Name of the file to contain the user name and password. If
-c is given, this file is created if it does not already exist, or
rewritten and truncated if it does exist.
-
username
- The username to create or update in passwdfile. If
username does not exist in this file, an entry is added. If it does
exist, the password is changed.
-
password
- The plaintext password to be hashed and stored in the file.
Only used with the -b flag.
htpasswd returns a zero status ("true") if the username and
password have been successfully added or updated in the
passwdfile.
htpasswd returns
1 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 if the file is not a valid password file.
htpasswd /usr/local/etc/apache/.htpasswd-users jsmith
Adds or modifies the password for user
jsmith. The user is prompted for
the password. The password will be hashed using the modified Apache MD5
algorithm. If the file does not exist,
htpasswd will do nothing except
return an error.
htpasswd -c /home/doe/public_html/.htpasswd 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
htpasswd will display a message and
return an error status.
htpasswd -db /usr/web/.htpasswd-all jones Pwd4Steve
Encrypts the password from the command line (
Pwd4Steve) using the
crypt() algorithm, and stores it in the specified file.
Web password files such as those managed by
htpasswd should
not be
within the Web server's URI space -- that is, they should not be fetchable
with a browser.
This program is not safe as a setuid executable. Do
not make it setuid.
The use of the
-b option is discouraged, since when it is used the
plaintext password appears on the command line.
When using the
crypt() 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-1 hashing format does not use salting: for a given password, there is
only one hashed representation. The
crypt() and MD5 formats permute the
representation by prepending a random salt string, to make dictionary attacks
against the passwords more difficult.
The SHA-1 and
crypt() formats are insecure by today's standards.
The SHA-2-based
crypt() formats (SHA-256 and SHA-512) are supported on
most modern Unix systems, and follow the specification at
https://www.akkadia.org/drepper/SHA-crypt.txt.
On the Windows platform, passwords hashed with
htpasswd are limited to no
more than
255 characters in length. Longer passwords will be truncated
to 255 characters.
The MD5 algorithm used by
htpasswd is specific to the Apache software;
passwords hashed using it will not be usable with other Web servers.
Usernames are limited to
255 bytes and may not include the character
:.
The cost of computing a bcrypt password hash value increases with the number of
rounds specified by the
-C option. The
apr-util library enforces
a maximum number of rounds of 17 in version
1.6.0 and later.