Resources available from the Apache HTTP server can be restricted to just the users listed in the files created by \fBhtpasswd\fR\&. This program can only manage usernames and passwords stored in a flat-file\&. It can encrypt and display password information for use in other types of data stores, though\&. To use a DBM database see dbmmanage or htdbm\&.
.PP
-\fBhtpasswd\fR encrypts passwords using either bcrypt, a version of MD5 modified for Apache, SHA1, or the system's \fBcrypt()\fR routine\&. Files managed by \fBhtpasswd\fR 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 \fBcrypt()\fR\&.
+\fBhtpasswd\fR encrypts passwords using either bcrypt, a version of MD5 modified for Apache, SHA-1, or the system's \fBcrypt()\fR routine\&. SHA-2-based hashes (SHA-256 and SHA-512) are supported for \fBcrypt()\fR\&. Files managed by \fBhtpasswd\fR 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 \fBcrypt()\fR\&.
.PP
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/\&.
Use MD5 encryption for passwords\&. This is the default (since version 2\&.2\&.18)\&.
.TP
+\fB-2\fR
+Use SHA-256 \fBcrypt()\fR based hashes for passwords\&. This is supported on most Unix platforms\&.
+.TP
+\fB-5\fR
+Use SHA-512 \fBcrypt()\fR based hashes for passwords\&. This is supported on most Unix platforms\&.
+.TP
\fB-B\fR
Use bcrypt encryption for passwords\&. This is currently considered to be very secure\&.
.TP
\fB-C\fR
This flag is only allowed in combination with \fB-B\fR (bcrypt encryption)\&. It sets the computing time used for the bcrypt algorithm (higher is more secure but slower, default: 5, valid: 4 to 17)\&.
.TP
+\fB-r\fR
+This flag is only allowed in combination with \fB-2\fR or \fB-5\fR\&. It sets the number of hash rounds used for the SHA-2 algorithms (higher is more secure but slower; the default is 5,000)\&.
+.TP
\fB-d\fR
Use \fBcrypt()\fR encryption 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 \fBinsecure\fR by today's standards\&. It used to be the default algorithm until version 2\&.2\&.17\&.
.TP
\fB-s\fR
-Use SHA encryption for passwords\&. Facilitates migration from/to Netscape servers using the LDAP Directory Interchange Format (ldif)\&. This algorithm is \fBinsecure\fR by today's standards\&.
+Use SHA-1 (160-bit) encryption for passwords\&. Facilitates migration from/to Netscape servers using the LDAP Directory Interchange Format (ldif)\&. This algorithm is \fBinsecure\fR by today's standards\&.
.TP
\fB-p\fR
Use plaintext passwords\&. Though \fBhtpasswd\fR will support creation on all platforms, the httpd daemon will only accept plain text passwords on Windows and Netware\&.
When using the \fBcrypt()\fR 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\&.
.PP
-The SHA encryption format does not use salting: for a given password, there is only one encrypted representation\&. The \fBcrypt()\fR and MD5 formats permute the representation by prepending a random salt string, to make dictionary attacks against the passwords more difficult\&.
+The SHA-1 encryption format does not use salting: for a given password, there is only one encrypted representation\&. The \fBcrypt()\fR and MD5 formats permute the representation by prepending a random salt string, to make dictionary attacks against the passwords more difficult\&.
+
+.PP
+The SHA-1 and \fBcrypt()\fR formats are insecure by today's standards\&.
.PP
-The SHA and \fBcrypt()\fR formats are insecure by today's standards\&.
+The SHA-2-based \fBcrypt()\fR 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\&.