DHCache

A micro Diffie-Hellman parameter generation web-service.

Notice: this readme is currently a CLI spec, and not indicitive of this project's current capabilities.

Synopsis

dhcache [-?hv] [-c|--config file] [-e|--error file] [-l|--listen address] [-p|--port number] [-w|--workers number] [--version] [bitsize:count]...

Description

Dhcache is a compact self-contained web-service that maintains a cache of independently generated Diffie-Hellman parameters at various bit lengths.

The options are as follows:

• -?, -h Display usage information.
• -c file, --config file Use an alternative configuration file.
• -e file, --error file Use an alternative error log file. The (default) special value of stderr indicates that the standard error output should be used.
• -l address, --listen address Listen on the specified address.
• -p number, --port number Listen on the specified port.
• -w number, --workers number Use the specified number of worker threads to generate Diffie-Hellman parameters. 0 automatically uses the maximum number of available cores.
• -v, --version Display the dhcache version.

Additionally, one or more Diffie-Hellman parameter sizes and counts can be specified on the command-line to indicate what size of parameters and how many should be generated and cached. Supported bitsizes include: 1024, 2048, 3072, 4096, 7680, 8192, 15360 and 16384.

The following URLs are exposed through the web-service:

• / provides a JSON encoded response listing available Diffie-Hellman parameters, including their bit sizes, available URLs, number currently cached, and intended number to cache.
• /:bitsize: returns a set of Diffie-Hellman parameters of the requested size. Possible response codes include:
  • An HTTP 200 (Ok) response code with the Diffie-Hellman parameters in the response body if there is a parameter of the requested size available.
  • An HTTP 503 (Service Unavailable) response code with a JSON encoded response if the cache for that configured Diffie-Hellman parameter size is currently unavailable.
  • An HTTP 404 (Not Found) response code with a JSON encoded response if dhcache isn't configured to provide the requested Diffie-Hellman parameter size.

Examples

The following command will start dhcache listening on all IPv4 addresses, port 80, using 4 workers to maintain a cache of 8 1024-bit, 4 2048-bit and 2 4096-bit Diffie-Hellman parameters:

$ dhcache -l 0 -p 80 -w 4 1024:8 2048:4 4096:2

The following command will start dhcache listening on the IPv6 loopback address, port 8080, using 2 workers to maintain a cache of 8 1024-bit Diffie-Hellman parameters:

$ dhcache -l ::1 -p 8080 -w 2 1024:8

The following command will start dhcache and pull all configuration information from it's default configuration file:

$ dhcache

The following command will start dhcache and pull all configuration information from the file located at /path/to/configuration:

$ dhcache -c /path/to/configuration