This repo contains the source code to build the utility program keystream_distribution, which computes the distribution of keystream bytes for rc4. This information can be useful for studying the security of real-world applications, and the implementation itself is a good example of the use of C++ for_each/accumulate with a parallel execution policy.
To build, install TBB (libtbb-dev) then run make. To run, see the usage below.
Usage: ./keystream_distribution [COMMAND], where COMMAND is one of:
Compute command:
[trials=<num>] [input=<file>] [output=<file>] [concurrency=<num>] [verbose]
performs trial computations and creates/updates distribution, where
trials=<num> performs <num> trials
input=<file> uses distribution in <file> as initial distribution
output=<file> writes final distribution to <file>
concurrency=<num> uses <num> threads of execution
Merge command:
merge <file1> <file2> [<file3> ... ] [output=<outfile>] [verbose]
reads distributions from two or more files, writes merged distribution
Help command:
help
prints out this usage guidance
NOTES
<num> can be an integer (e.g. 1024) or power of 2 (e.g. 2^10)
if output=<file> is not specified, the standard output is used
if conncurency=<num> is not specified, the number of cores is used
verbose keyword sends verbose output to standard error
FILE FORMAT
cnt[i][j] counts the number of times the i^th byte of keystream equals j
This code is licensend under a New BSD license.