4.3.2.2 Invoking srptool

Simple program that emulates the programs in the Stanford SRP (Secure Remote Password) libraries using GnuTLS. It is intended for use in places where you don’t expect SRP authentication to be the used for system users.

In brief, to use SRP you need to create two files. These are the password file that holds the users and the verifiers associated with them and the configuration file to hold the group parameters (called tpasswd.conf).

srptool help/usage (-?)

The text printed is the same whether selected with the help option (--help) or the more-help option (--more-help). more-help will print the usage text by passing it through a pager program. more-help is disabled on platforms without a working fork(2) function. The PAGER environment variable is used to select the program, defaulting to more. Both will exit with a status code of 0.

srptool - GnuTLS SRP tool
Usage:  srptool [ -<flag> [<val>] | --<name>[{=| }<val>] ]... 

None:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
   -i, --index=num            specify the index of the group parameters in tpasswd.conf to use
   -u, --username=str         specify a username
   -p, --passwd=str           specify a password file
   -s, --salt=num             specify salt size
       --verify               just verify the password
   -v, --passwd-conf=str      specify a password conf file
       --create-conf=str      Generate a password configuration file

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.

Simple program that emulates the programs in the Stanford SRP (Secure
Remote Password) libraries using GnuTLS.  It is intended for use in  places
where you don't expect SRP authentication to be the used for system users.

In  brief,  to use SRP you need to create two files. These are the password
file that holds the users and the verifiers associated with  them  and  the
configuration file to hold the group parameters (called tpasswd.conf).

Please send bug reports to:  <bugs@gnutls.org>

debug option (-d).

This is the “enable debugging” option. This option takes a ArgumentType.NUMBER argument. Specifies the debug level.

verify option.

This is the “just verify the password” option. Verifies the password provided against the password file.

passwd-conf option (-v).

This is the “specify a password conf file” option. This option takes a ArgumentType.STRING argument. Specify a filename or a PKCS #11 URL to read the CAs from.

create-conf option.

This is the “generate a password configuration file” option. This option takes a ArgumentType.STRING argument. This generates a password configuration file (tpasswd.conf) containing the required for TLS parameters.

version option (-v).

This is the “output version information and exit” option. This option takes a ArgumentType.KEYWORD argument. Output version of program and exit. The default mode is ‘v’, a simple version. The ‘c’ mode will print copyright information and ‘n’ will print the full copyright notice.

help option (-h).

This is the “display extended usage information and exit” option. Display usage information and exit.

more-help option (-!).

This is the “extended usage information passed thru pager” option. Pass the extended usage information through a pager.

srptool exit status

One of the following exit values will be returned:

‘0 (EXIT_SUCCESS)’

Successful program execution.

‘1 (EXIT_FAILURE)’

The operation failed or the command syntax was not valid.

srptool See Also

gnutls-cli-debug (1), gnutls-serv (1), srptool (1), psktool (1), certtool (1)

srptool Examples

To create tpasswd.conf which holds the g and n values for SRP protocol (generator and a large prime), run:

$ srptool --create-conf /etc/tpasswd.conf

This command will create /etc/tpasswd and will add user ’test’ (you will also be prompted for a password). Verifiers are stored by default in the way libsrp expects.

$ srptool --passwd /etc/tpasswd --passwd-conf /etc/tpasswd.conf -u test

This command will check against a password. If the password matches the one in /etc/tpasswd you will get an ok.

$ srptool --passwd /etc/tpasswd --passwd\-conf /etc/tpasswd.conf --verify -u test