X12

Copyright (c) 2014-2017, The X12 Project

Development Resources

• GitHub: https://github.com/kingrobert/x12-wallet

Build

Operating System	Processor	Status
Ubuntu 16.04	i686	[![Ubuntu 16.04 i686]
Ubuntu 16.04	amd64	[![Ubuntu 16.04 amd64]
Ubuntu 16.04	armv7	[![Ubuntu 16.04 armv7]
OSX 10.10	amd64	[![OSX 10.10 amd64]
OSX 10.11	amd64	[![OSX 10.11 amd64]
OSX 10.12	amd64	[![OSX 10.12 amd64]
Windows (MSYS2/MinGW)	i686	[![Windows (MSYS2/MinGW) i686]
Windows (MSYS2/MinGW)	amd64	[![Windows (MSYS2/MinGW) amd64]

Introduction

X12 is a private, secure, untraceable, decentralised digital currency. You are your bank, you control your funds, and nobody can trace your transfers unless you allow them to do so.

Privacy: X12 uses a cryptographically sound system to allow you to send and receive funds without your transactions being easily revealed on the blockchain (the ledger of transactions that everyone has). This ensures that your purchases, receipts, and all transfers remain absolutely private by default.

Security: Using the power of a distributed peer-to-peer consensus network, every transaction on the network is cryptographically secured. Individual wallets have a 25 word mnemonic seed that is only displayed once, and can be written down to backup the wallet. Wallet files are encrypted with a passphrase to ensure they are useless if stolen.

Untraceability: By taking advantage of ring signatures, a special property of a certain type of cryptography, X12 is able to ensure that transactions are not only untraceable, but have an optional measure of ambiguity that ensures that transactions cannot easily be tied back to an individual user or computer.

About this Project

This is the core implementation of X12.

License

See LICENSE.

Compiling X12 from Source

Dependencies

The following table summarizes the tools and libraries required to build. A few of the libraries are also included in this repository (marked as "Vendored"). By default, the build uses the library installed on the system, and ignores the vendored sources. However, if no library is found installed on the system, then the vendored source will be built and used. The vendored sources are also used for statically-linked builds because distribution packages often include only shared library binaries (.so) but not static library archives (.a).

Dep	Min. Version	Vendored	Debian/Ubuntu Pkg	Arch Pkg	Optional	Purpose
GCC	4.7.3	NO	build-essential	base-devel	NO
CMake	3.0.0	NO	cmake	cmake	NO
pkg-config	any	NO	pkg-config	base-devel	NO
Boost	1.58	NO	libboost-all-dev	boost	NO	C++ libraries
OpenSSL	basically any	NO	libssl-dev	openssl	NO	sha256 sum
libunbound	1.4.16	YES	libunbound-dev	unbound	NO	DNS resolver
libminiupnpc	2.0	YES	libminiupnpc-dev	miniupnpc	YES	NAT punching
libunwind	any	NO	libunwind8-dev	libunwind	YES	Stack traces
liblzma	any	NO	liblzma-dev	xz	YES	For libunwind
ldns	1.6.17	NO	libldns-dev	ldns	YES	SSL toolkit
expat	1.1	NO	libexpat1-dev	expat	YES	XML parsing
GTest	1.5	YES	libgtest-dev^	gtest	YES	Test suite
Doxygen	any	NO	doxygen	doxygen	YES	Documentation
Graphviz	any	NO	graphviz	graphviz	YES	Documentation

[^] On Debian/Ubuntu libgtest-dev only includes sources and headers. You must build the library binary manually. This can be done with the following command sudo apt-get install libgtest-dev && cd /usr/src/gtest && sudo cmake . && sudo make && sudo mv libg* /usr/lib/

Build instructions

X12 uses the CMake build system and a top-level Makefile that invokes cmake commands as needed.

On Linux and OS X

• Install the dependencies

• Change to the root of the source code directory and build:

    cd x12-core
    make
  

  Optional: If your machine has several cores and enough memory, enable parallel build by running make -j<number of threads> instead of make. For this to be worthwhile, the machine should have one core and about 2GB of RAM available per thread.

• The resulting executables can be found in build/release/bin

• Add PATH="$PATH:$HOME/x12-core/build/release/bin" to .profile

• Run X12 with x12coind --detach

• Optional: build and run the test suite to verify the binaries:

    make release-test
  

  NOTE: coretests test may take a few hours to complete.

• Optional: to build binaries suitable for debugging:

     make debug
  

• Optional: to build statically-linked binaries:

     make release-static
  

• Optional: build documentation in doc/html (omit HAVE_DOT=YES if graphviz is not installed):

    HAVE_DOT=YES doxygen Doxyfile
  

On Windows:

Binaries for Windows are built on Windows using the MinGW toolchain within MSYS2 environment. The MSYS2 environment emulates a POSIX system. The toolchain runs within the environment and cross-compiles binaries that can run outside of the environment as a regular Windows application.

Preparing the Build Environment

• Download and install the MSYS2 installer, either the 64-bit or the 32-bit package, depending on your system.

• Open the MSYS shell via the MSYS2 Shell shortcut

• Update packages using pacman:

    pacman -Syuu  
  

• Exit the MSYS shell using Alt+F4

• Edit the properties for the MSYS2 Shell shortcut changing "msys2_shell.bat" to "msys2_shell.cmd -mingw64" for 64-bit builds or "msys2_shell.cmd -mingw32" for 32-bit builds

• Restart MSYS shell via modified shortcut and update packages again using pacman:

    pacman -Syuu  
  

• Install dependencies:

  To build for 64-bit Windows:

    pacman -S mingw-w64-x86_64-toolchain make mingw-w64-x86_64-cmake mingw-w64-x86_64-boost
  

  To build for 32-bit Windows:

    pacman -S mingw-w64-i686-toolchain make mingw-w64-i686-cmake mingw-w64-i686-boost
  

• Open the MingW shell via MinGW-w64-Win64 Shell shortcut on 64-bit Windows or MinGW-w64-Win64 Shell shortcut on 32-bit Windows. Note that if you are running 64-bit Windows, you will have both 64-bit and 32-bit MinGW shells.

Building

• If you are on a 64-bit system, run:

    make release-static-win64
  

• If you are on a 32-bit system, run:

    make release-static-win32
  

• The resulting executables can be found in build/release/bin

Running x12coind

The build places the binary in bin/ sub-directory within the build directory from which cmake was invoked (repository root by default). To run in foreground:

./bin/x12coind

To list all available options, run ./bin/x12coind --help. Options can be specified either on the command line or in a configuration file passed by the --config-file argument. To specify an option in the configuration file, add a line with the syntax argumentname=value, where argumentname is the name of the argument without the leading dashes, for example log-level=1.

To run in background:

./bin/x12coind --log-file x12coind.log --detach

To run as a systemd service, copy x12coind.service to /etc/systemd/system/ and x12coind.conf to /etc/. The example service assumes that the user x12 exists and its home is the data directory specified in the example config.

If you're on Mac, you may need to add the --max-concurrency 1 option to x12coin-wallet-cli, and possibly x12coind, if you get crashes refreshing.

Internationalization

See README.i18n.

Using Tor

While X12 isn't made to integrate with Tor, it can be used wrapped with torsocks, if you add --p2p-bind-ip 127.0.0.1 to the x12coind command line. You also want to set DNS requests to go over TCP, so they'll be routed through Tor, by setting DNS_PUBLIC=tcp. You may also disable IGD (UPnP port forwarding negotiation), which is pointless with Tor. To allow local connections from the wallet, you might have to add TORSOCKS_ALLOW_INBOUND=1, some OSes need it and some don't. Example:

DNS_PUBLIC=tcp torsocks x12coind --p2p-bind-ip 127.0.0.1 --no-igd

or:

DNS_PUBLIC=tcp TORSOCKS_ALLOW_INBOUND=1 torsocks x12coind --p2p-bind-ip 127.0.0.1 --no-igd

TAILS ships with a very restrictive set of firewall rules. Therefore, you need to add a rule to allow this connection too, in addition to telling torsocks to allow inbound connections. Full example:

sudo iptables -I OUTPUT 2 -p tcp -d 127.0.0.1 -m tcp --dport 18781 -j ACCEPT

DNS_PUBLIC=tcp torsocks ./x12coind --p2p-bind-ip 127.0.0.1 --no-igd --rpc-bind-ip 127.0.0.1 --data-dir /home/amnesia/Persistent/your/directory/to/the/blockchain

./x12coin-wallet-cli

Using readline

While x12coind and x12coin-wallet-cli do not use readline directly, most of the functionality can be obtained by running them via rlwrap. This allows command recall, edit capabilities, etc. It does not give autocompletion without an extra completion file, however. To use rlwrap, simply prepend rlwrap to the command line, eg:

rlwrap bin/x12coin-wallet-cli --wallet-file /path/to/wallet

Note: rlwrap will save things like your seed and private keys, if you supply them on prompt. You may want to not use rlwrap when you use simplewallet to restore from seed, etc.

Debugging

This section contains general instructions for debugging failed installs or problems encountered with X12. First ensure you are running the latest version built from the github repo.

Obtaining Stack Traces and Core Dumps on Unix Systems

We generally use the tool gdb (GNU debugger) to provide stack trace functionality, and ulimit to provide core dumps in builds which crash or segfault.

• To use gdb in order to obtain a stack trace for a build that has stalled:

Run the build.

Once it stalls, enter the following command:

gdb /path/to/x12coind `pidof x12coind` 

Type thread apply all bt within gdb in order to obtain the stack trace

• If however the core dumps or segfaults:

Enter ulimit -c unlimited on the command line to enable unlimited filesizes for core dumps

Run the build.

When it terminates with an output along the lines of "Segmentation fault (core dumped)", there should be a core dump file in the same directory as x12coind.

You can now analyse this core dump with gdb as follows:

gdb /path/to/x12coind /path/to/dumpfile

Print the stack trace with bt

• To run x12 within gdb:

Type gdb /path/to/x12coind

Pass command-line options with --args followed by the relevant arguments

Type run to run x12coind

Analysing Memory Corruption

We use the tool valgrind for this.

Run with valgrind /path/to/x12coind. It will be slow.

LMDB

Instructions for debugging suspected blockchain corruption as per @HYC

There is an mdb_stat command in the LMDB source that can print statistics about the database but it's not routinely built. This can be built with the following command:

cd ~/x12/external/db_drivers/liblmdb && make

The output of mdb_stat -ea <path to blockchain dir> will indicate inconsistencies in the blocks, block_heights and block_info table.

The output of mdb_dump -s blocks <path to blockchain dir> and mdb_dump -s block_info <path to blockchain dir> is useful for indicating whether blocks and block_info contain the same keys.

These records are dumped as hex data, where the first line is the key and the second line is the data.