The sha256 program calculates and prints SHA-256 (256bit) checksums of all files that are passed to it as command line parameters. It can also be used to calculate SHA-1 (160bit), SHA-224 (224bit), SHA-384 (384bit) and SHA-512 (512bit) checksums, if desired.
Since this (obviously) is a command line program, you can call it via command line/ shell. A list of valid options follows below.
sha256 [--sha1 | --sha224 | --sha256 | --sha384 | --sha512] FILENAME ...
--sha1 Calculate SHA-1 (160 bit) checksums instead of SHA-256.
--sha224 Calculate SHA-224 (224 bit) checksums instead of SHA-256.
--sha256 Calculate SHA-256 (256 bit) checksums. This is the default.
--sha384 Calculate SHA-384 (384 bit) checksums instead of SHA-256.
--sha512 Calculate SHA-512 (512 bit) checksums instead of SHA-256.
--help Show a help message and list valid program options.
--version Print version information and quit.
FILENAME path to a file that should be hashed. Can be repeated multiple times.
A typical call could look like:
sha256 foo.txt some_dir/bar.baz
This would calculate the SHA-256 message digests of foo.txt and bar.baz in the subdirectory some_dir. If one of the given files does not exist, the program quits.
To build sha256 from source you need a C++ compiler with support for C++11 and CMake 3.8 or later. It also helps to have Git, a distributed version control system, on your build system to get the latest source code directly from the Git repository.
All three can usually be installed be typing
apt-get install cmake g++ git
or
yum install cmake gcc-c++ git
into a root terminal.
Get the source directly from Git by cloning the Git repository and change to the directory after the repository is completely cloned:
git clone https://gitlab.com/striezel/secure-hash-algorithm.git ./sha256
cd sha256
git submodule update --init --recursive
The last of the lines above initializes and updates the submodule that the sha256 source code needs, too, to be build from source.
The build process is relatively easy, because CMake does all the preparations. Starting in the root directory of the source, you can do the following steps:
mkdir build
cd build
cmake ../
make sha256 -j2
Now the sha256 binary is built and ready for use.
Copyright 2015 Dirk Stolle
The program sha256 is released under the GNU General Public License version 3, a free software license. For the full text of the license consult the file LICENSE or view it online at http://www.gnu.org/licenses/gpl-3.0.html
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHAN- TABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
The program's source code is published at GitLab.com, the project itself is located at https://gitlab.com/striezel/secure-hash-algorithm