BLOCKHASHMAKE(1)

NAME

blockHashMake - Make a block hash file for Deadwood

DESCRIPTION

blockHashMake is a stand alone command line tool which converts a list of host names in to a block hash file which Deadwood can read to block a large number of hosts quickly while using a minimum amount of memory to store the list of blocked hosts.

A block hash file uses a special binary format for storing a list of blocked host names.

blockHashMake reads the list of host names from the standard input and generates a binary file.

COMMAND LINE ARGUMENTS

blockHashMake can be invoked without command line arguments. If invoked without arguments, blockHashMake reads the list of host names to block from standard input and outputs the block hash to a file name "bigBlock.bin"

blockHashMake can be invoked with a single "--help" or "--version" command line argument (e.g. "blockHashMake --version") which will output the version number of blockHashMake and provide basic usage information.

The command line arguments are as follows:
blockHashMake [filename] [sip hash key] [hash bucket count]
The filename is the name of the file we output the block hash to. If not specified, blockHashMake will output to the file named "bigBlock.bin". blockHashMake should not clobber an already existing file; if a file named "bigBlock.bin" (or the filename specified on the command line) already exists, be sure to delete the file before invoking blockHashMake to recreate the file.

The sip hash key is usually set by the blockHashMake program, which, by default, uses /dev/urandom to generate a random 64-bit key for the block hash file (the Windows port of blockHashMake uses the CryptGenRandom function to get a random 64-bit key). If the sip hash key is given a value of 0, this can make a block hash file which can be shared on the internet.

Warning: For security purposes, please set the sip hash key to 0 if sharing a block hash file on the internet!

Deadwood will only load a block hash file with a sip hash key of 0 if allow_block_hash_zero_key has a value of 1.

A user specified sip hash key only has up to 16 bits of entropy. sip hash key should not be used if a secret key for the hash compression algorithm is desired.

The hash bucket count is the number of hash buckets the resulting block hash file will have. Having more hash buckets makes the block hash file larger, but sometimes allows searching for a string in a block hash to be a little faster. The default value, which is 125% of the number of host names given to blockHashMake, is a reasonable compromise between speed and size.

HOST LIST FORMAT

After being invoked, blockHashMake reads a list of host names from the standard input. The format is a single host name per line of input, such as the following:
porn.example.com
naughty.foo
evil.host.invalid
Each line is a host name. Should there be a duplicate host name, blockHashMake will only store one instance of the host name in question. Host names are case insensitive; upper case ASCII letters are converted in to lower case letters beofre adding the host name to the block hash generated by blockHashMake.

blockHashMake has no support for Punycode. Please use another program to convert international domain names with non-ASCII characters in to their punycode representation before adding them to a block hash with blockHashMake.

LIMITATIONS

The block hash format that blockHashMake uses is a 32-bit format, and the resulting block hash file should be under 2,147,483,648 bytes in size. This is a limitation of around 30 million host names.

LEGAL DISCLAIMERS

THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

This is a project developed on a strictly volunteer, non-commercial basis. It has been developed outside the course of a commercial activity, developed entirely in the Americas (i.e. outside of Europe) and therefore is not subject to the restrictions or conditions of the proposed EU Cyber Resilience Act. Someone selling a product that uses any component of this may be subject to this act and may need to handle any and all necessary compliance.

AUTHORS

Sam Trenholme (https://www.samiam.org) is responsible for this program and man page.