Charnacoin

Copyright (c) 2017, The Charnacoin Project

Development Resources

• Web: charnacoin.com
• Mail: crypto@charnacoin.com
• Github: https://github.com/charnacrypto/charnacoin
• IRC: #charnacoin-dev on Freenode

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Introduction

As Cryptonote/Monero based technology, Charnacoin 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: Charnacoin 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, Charnacoin 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 Charnacoin. It is open source and completely free to use without restrictions, except for those specified in the license agreement below. There are no restrictions on anyone creating an alternative implementation of Charnacoin that uses the protocol and network in a compatible manner.

As with many development projects, the repository on Github is considered to be the "staging" area for the latest changes. Before changes are merged into that branch on the main repository, they are tested by individual developers in their own branches, submitted as a pull request, and then subsequently tested by contributors who focus on testing and code reviews. Monero's development is also well followed to sweet futur improvements according to charnacoin own behavior. That having been said, the repository should be carefully considered before using it in a production environment, unless there is a patch in the repository for a particular show-stopping issue you are experiencing. It is generally a better idea to use a tagged release for stability.

Anyone is welcome to contribute to Charnacoin's codebase! If you have a fix or code change, feel free to submit is as a pull request directly to the "master" branch. In cases where the change is relatively small or does not affect other parts of the codebase it may be merged in immediately by any one of the collaborators. On the other hand, if the change is particularly large or complex, it is expected that it will be discussed at length either well in advance of the pull request being submitted, or even directly on the pull request.

Supporting the Project

harnacoin development can be supported directly through donations.

Both Charnacoin and Bitcoin donations can be made to charnacoin.com/donate.

The Charnacoin donation address is: Cjo7trECi42f2Ph7BJtxc5e2fGtmpVkXLYyE5ynhnnf41p4n9oN3zn696muBZX6CBca8q1c46T5H8ZSKhLHtR2MGCrjLyoZ (viewkey: )

The Monero donation address is: 43Tob1j6gqcNGvM46xx5xiWqskj4DguW3jnHgGZAfD9KXLrcmxM3nQgT3sasEfaNqcWb5qRjsZzaUg2bdne54TaGBsra1CW

The Bitcoin donation address is: 131BRfZ1rmPApxo2GWiY8GwAodotXy5hCF

Note: you can easily donate NAC to the Charnacoin donation address by using the donate command. Type help in the command-line wallet for details.

License

See LICENSE.

Charnacoin software updates and consensus protocol changes (hard fork schedule)

Charnacoin uses a fixed-schedule hard fork mechanism to implement new features. This means that users of Charnacoin (end users and service providers) need to run current versions and update their software on a regular schedule. Here is the current schedule, versions, and compatibility.Dates are provided in the format YYYY-MM-DD.

Installing Charnacoin from a Package

• Docker

    docker build -t charnacoin .
  
    # either run in foreground
    docker run -it -v /charnacoin/chain:/root/.charnacoin -v /charnacoin/wallet:/wallet -p 18090:18090 charnacoin
  
    # or in background
    docker run -it -d -v /charnacoin/chain:/root/.charnacoin -v /charnacoin/wallet:/wallet -p 18090:18090 charnacoin
  

Packaging for your favorite distribution would be a welcome contribution!

Compiling Charnacoin from Source

Dependencies

The following table summarizes the tools and libraries required to build. Afew 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 onthe system, then the vendored source will be built and used. The vendoredsources are also used for statically-linked builds because distributionpackages often include only shared library binaries (.so) but not staticlibrary archives (.a).

[^] On Debian/Ubuntu libgtest-dev only includes sources and headers. You mustbuild 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

Charnacoin uses the CMake build system and a top-level Makefile thatinvokes cmake commands as needed.

On Linux and OS X

• Install the dependencies

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

    cd charnacoin
    make
  

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

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

• Add PATH="$PATH:$HOME/charnacoin/build/release/bin" to .profile

• Run Charnacoin with charnacoind --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 the Raspberry Pi

Tested on a Raspberry Pi 2 with a clean install of minimal Debian Jessie from https://www.raspberrypi.org/downloads/raspbian/

• apt-get update && apt-get upgrade to install all of the latest software

• Install the dependencies for Charnacoin except libunwind and libboost-all-dev

• Increase the system swap size:

	sudo /etc/init.d/dphys-swapfile stop  
	sudo nano /etc/dphys-swapfile  
	CONF_SWAPSIZE=1024  
	sudo /etc/init.d/dphys-swapfile start  

• Install the latest version of boost (this may first require invoking apt-get remove --purge libboost* to remove a previous version if you're not using a clean install):

	cd  
	wget https://sourceforge.net/projects/boost/files/boost/1.62.0/boost_1_62_0.tar.bz2  
	tar xvfo boost_1_62_0.tar.bz2  
	cd boost_1_62_0  
	./bootstrap.sh  
	sudo ./b2  

• Wait ~8 hours

  sudo ./bjam install

• Wait ~4 hours

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

    cd charnacoin
    make release
  

• Wait ~4 hours

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

• Add PATH="$PATH:$HOME/charnacoin/build/release/bin" to .profile

• Run Charnacoin with charnacoind --detach

• You may wish to reduce the size of the swap file after the build has finished, and delete the boost directory from your home directory

On Windows:

Binaries for Windows are built on Windows using the MinGW toolchain withinMSYS2 environment. The MSYS2 environment emulates aPOSIX system. The toolchain runs within the environment and cross-compilesbinaries that can run outside of the environment as a regular Windowsapplication.

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 Windowsor MinGW-w64-Win64 Shell shortcut on 32-bit Windows. Note that if you arerunning 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

On FreeBSD:

The project can be built from scratch by following instructions for Linux above. If you are running charnacoin in a jail you need to add the flag: allow.sysvipc=1 to your jail configuration, otherwise lmdb will throw the error message: Failed to open lmdb environment: Function not implemented.

We expect to add Charnacoin into the ports tree in the near future, which will aid in managing installations using ports or packages.

On OpenBSD:

This has been tested on OpenBSD 5.8.

You will need to add a few packages to your system. pkg_add db cmake gcc gcc-libs g++ miniupnpc gtest.

The doxygen and graphviz packages are optional and require the xbase set.

The Boost package has a bug that will prevent librpc.a from building correctly. In order to fix this, you will have to Build boost yourself from scratch. Follow the directions here (under "Building Boost"):https://github.com/bitcoin/bitcoin/blob/master/doc/build-openbsd.md

You will have to add the serialization, date_time, and regex modules to Boost when building as they are needed by Charnacoin.

To build: env CC=egcc CXX=eg++ CPP=ecpp DEVELOPER_LOCAL_TOOLS=1 BOOST_ROOT=/path/to/the/boost/you/built make release-static-64

Building Portable Statically Linked Binaries

By default, in either dynamically or statically linked builds, binaries target the specific host processor on which the build happens and are not portable to other processors. Portable binaries can be built using the following targets:

• make release-static-64 builds binaries on Linux on x86_64 portable across POSIX systems on x86_64 processors
• make release-static-32 builds binaries on Linux on x86_64 or i686 portable across POSIX systems on i686 processors
• make release-static-armv8 builds binaries on Linux portable across POSIX systems on armv8 processors
• make release-static-armv7 builds binaries on Linux portable across POSIX systems on armv7 processors
• make release-static-armv6 builds binaries on Linux portable across POSIX systems on armv6 processors
• make release-static-win64 builds binaries on 64-bit Windows portable across 64-bit Windows systems
• make release-static-win32 builds binaries on 64-bit or 32-bit Windows portable across 32-bit Windows systems

Running charnacoind

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

./bin/charnacoind

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

To run in background:

./bin/charnacoind --log-file charnacoind.log --detach

To run as a systemd service, copycharnacoind.service to /etc/systemd/system/ andcharnacoind.conf to /etc/. The exampleservice assumes that the user charnacoin existsand its home is the data directory specified in the exampleconfig.

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

Internationalization

See README.i18n

Using Tor

While Charnacoin 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 charnacoind 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 charnacoind --p2p-bind-ip 127.0.0.1 --no-igd

or:

DNS_PUBLIC=tcp TORSOCKS_ALLOW_INBOUND=1 torsocks charnacoind --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 18091 -j ACCEPT

DNS_PUBLIC=tcp torsocks ./charnacoind --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

./charnacoin-wallet-cli

Using readline

While charnacoind and charnacoin-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/charnacoin-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.

Contributing

If you want to help out, see CONTRIBUTING for a set of guidelines.

Debugging

This section contains general instructions for debugging failed installs or problems encountered with Charnacoin. 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/charnacoind `pidof charnacoind` 

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 charnacoind.

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

gdb /path/to/charnacoind /path/to/dumpfile

Print the stack trace with bt

• To run charnacoin within gdb:

Type gdb /path/to/charnacoind

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

Type run to run charnacoind

Analysing Memory Corruption

We use the tool valgrind for this.

Run with valgrind /path/to/charnacoind. 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 ~/charnacoin/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.