Copyright (c) 2018-2020 The Scala Network.
Copyright (c) 2014-2019 The Monero Project.
Portions Copyright (c) 2012-2013 The Cryptonote developers.
- Development resources
- Vulnerability response
- Announcements
- Introduction
- About this project
- Supporting the project
- License
- Contributing
- Scheduled software upgrades
- Compiling Scala from source
- Internationalization
- Using Tor
- Debugging
- Known issues
- Web: scalaproject.io
- Forum: discord
- Mail: [email protected]
- GitHub: https://github.com/scala-network/scala
- It is HIGHLY recommended that you join the discord channel if you are developing software that uses Scala. Due to the nature of this open source software project, joining this channel and idling is the best way to stay updated on best practices and new developments in the Scala ecosystem. All you need to do is join the discord channel and idle to stay updated with the latest in Scala development. If you do not, you risk wasting resources on developing integrations that are not compatible with the Scala network. The Scala core team and community continuously make efforts to communicate updates, developments, and documentation via other platforms – but for the best information, you need to talk to other Scala developers, and they are on discord.
Please reach out to us at [email protected] if you would like to report any vulnerabilities in the Scala codebase.
- You can follow our twitter to get all the new information regarding the project.
Scala 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: Scala 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, Scala 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.
Decentralization: The utility of scala depends on its decentralised peer-to-peer consensus network - anyone should be able to run the scala software, validate the integrity of the blockchain, and participate in all aspects of the scala network using consumer-grade commodity hardware. Decentralization of the scala network is maintained by software development that minimizes the costs of running the scala software and inhibits the proliferation of specialized, non-commodity hardware.
This is the core implementation of Scala. 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 Scala 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. 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 Scala's codebase! If you have a fix or code change, feel free to submit it 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.
See LICENSE.
If you want to help out, see CONTRIBUTING for a set of guidelines.
Scala uses a fixed-schedule software upgrade (hard fork) mechanism to implement new features. This means that users of Scala (end users and service providers) should run current versions and upgrade their software on a regular schedule.
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 | Void pkg | Fedora pkg | Optional | Purpose |
|---|---|---|---|---|---|---|---|---|
| GCC | 4.7.3 | NO | build-essential |
base-devel |
base-devel |
gcc |
NO | |
| CMake | 3.5 | NO | cmake |
cmake |
cmake |
cmake |
NO | |
| pkg-config | any | NO | pkg-config |
base-devel |
base-devel |
pkgconf |
NO | |
| Boost | 1.58 | NO | libboost-all-dev |
boost |
boost-devel |
boost-devel |
NO | C++ libraries |
| OpenSSL | basically any | NO | libssl-dev |
openssl |
libressl-devel |
openssl-devel |
NO | sha256 sum |
| libzmq | 3.0.0 | NO | libzmq3-dev |
zeromq |
zeromq-devel |
zeromq-devel |
NO | ZeroMQ library |
| OpenPGM | ? | NO | libpgm-dev |
libpgm |
openpgm-devel |
NO | For ZeroMQ | |
| libnorm[2] | ? | NO | libnorm-dev |
YES | For ZeroMQ | |||
| libunbound | 1.4.16 | YES | libunbound-dev |
unbound |
unbound-devel |
unbound-devel |
NO | DNS resolver |
| libsodium | ? | NO | libsodium-dev |
libsodium |
libsodium-devel |
libsodium-devel |
NO | cryptography |
| libunwind | any | NO | libunwind8-dev |
libunwind |
libunwind-devel |
libunwind-devel |
YES | Stack traces |
| liblzma | any | NO | liblzma-dev |
xz |
liblzma-devel |
xz-devel |
YES | For libunwind |
| libreadline | 6.3.0 | NO | libreadline6-dev |
readline |
readline-devel |
readline-devel |
YES | Input editing |
| ldns | 1.6.17 | NO | libldns-dev |
ldns |
libldns-devel |
ldns-devel |
YES | SSL toolkit |
| expat | 1.1 | NO | libexpat1-dev |
expat |
expat-devel |
expat-devel |
YES | XML parsing |
| GTest | 1.5 | YES | libgtest-dev[1] |
gtest |
gtest-devel |
gtest-devel |
YES | Test suite |
| Doxygen | any | NO | doxygen |
doxygen |
doxygen |
doxygen |
YES | Documentation |
| Graphviz | any | NO | graphviz |
graphviz |
graphviz |
graphviz |
YES | Documentation |
| lrelease | ? | NO | qttools5-dev-tools |
qt5-tools |
qt5-tools |
qt5-linguist |
YES | Translations |
| libhidapi | ? | NO | libhidapi-dev |
hidapi |
hidapi-devel |
hidapi-devel |
YES | Hardware wallet |
| libusb | ? | NO | libusb-dev |
libusb |
libusb-devel |
libusb-devel |
YES | Hardware wallet |
| libprotobuf | ? | NO | libprotobuf-dev |
protobuf |
protobuf-devel |
protobuf-devel |
YES | Hardware wallet |
| protoc | ? | NO | protobuf-compiler |
protobuf |
protobuf |
protobuf-compiler |
YES | Hardware wallet |
[1] 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/
[2] libnorm-dev is needed if your zmq library was built with libnorm, and not needed otherwise
Install all dependencies at once on Debian/Ubuntu:
sudo apt update && sudo apt install build-essential cmake pkg-config libboost-all-dev libssl-dev libzmq3-dev libunbound-dev libsodium-dev libunwind8-dev liblzma-dev libreadline6-dev libldns-dev libexpat1-dev doxygen graphviz libpgm-dev qttools5-dev-tools libhidapi-dev libusb-dev libprotobuf-dev protobuf-compiler
Install all dependencies at once on macOS with the provided Brewfile:
brew update && brew bundle --file=contrib/brew/Brewfile
FreeBSD one liner for required to build dependencies
pkg install git gmake cmake pkgconf boost-libs libzmq libsodium
Clone recursively to pull-in needed submodule(s):
$ git clone --recursive https://github.com/scala-network/scala
If you already have a repo cloned, initialize and update:
$ cd scala && git submodule init && git submodule update
Scala uses the CMake build system and a top-level Makefile that invokes cmake commands as needed.
-
Install the dependencies
-
Change to the root of the source code directory, change to the most recent release branch, and build:
cd scala makeOptional: If your machine has several cores and enough memory, enable parallel build by running
make -j<number of threads>instead ofmake. 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/scala/build/release/bin"to.profile -
Run Scala with
scalad --detach -
Optional: build and run the test suite to verify the binaries:
make release-test
NOTE:
core_teststest 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
Dependencies need to be built with -fPIC. Static libraries usually aren't, so you may have to build them yourself with -fPIC. Refer to their documentation for how to build them.
-
Optional: build documentation in
doc/html(omitHAVE_DOT=YESifgraphvizis not installed):HAVE_DOT=YES doxygen Doxyfile
Tested on a Raspberry Pi Zero with a clean install of minimal Raspbian Stretch (2017-09-07 or later) from https://www.raspberrypi.org/downloads/raspbian/. If you are using Raspian Jessie, please see note in the following section.
-
apt-get update && apt-get upgradeto install all of the latest software -
Install the dependencies for Scala from the 'Debian' column in the table above.
-
Increase the system swap size:
sudo /etc/init.d/dphys-swapfile stop sudo nano /etc/dphys-swapfile CONF_SWAPSIZE=2048 sudo /etc/init.d/dphys-swapfile start
-
If using an external hard disk without an external power supply, ensure it gets enough power to avoid hardware issues when syncing, by adding the line "max_usb_current=1" to /boot/config.txt
-
Clone scala and checkout the most recent release version:
git clone --recurisive https://github.com/scala-network/scala.git cd scala -
Build:
make release
-
Wait 4-6 hours
-
The resulting executables can be found in
build/release/bin -
Add
PATH="$PATH:$HOME/scala/build/release/bin"to.profile -
Run Scala with
scalad --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
If you are using the older Raspbian Jessie image, compiling Scala is a bit more complicated. The version of Boost available in the Debian Jessie repositories is too old to use with Scala, and thus you must compile a newer version yourself. The following explains the extra steps, and has been tested on a Raspberry Pi 2 with a clean install of minimal Raspbian Jessie.
-
As before,
apt-get update && apt-get upgradeto install all of the latest software, and increase the system swap sizesudo /etc/init.d/dphys-swapfile stop sudo nano /etc/dphys-swapfile CONF_SWAPSIZE=2048 sudo /etc/init.d/dphys-swapfile start
-
Then, install the dependencies for Scala except
libunwindandlibboost-all-dev -
Install the latest version of boost (this may first require invoking
apt-get remove --purge libboost*-devto remove a previous version if you're not using a clean install):cd wget https://sourceforge.net/projects/boost/files/boost/1.72.0/boost_1_72_0.tar.bz2 tar xvfo boost_1_72_0.tar.bz2 cd boost_1_72_0 ./bootstrap.sh sudo ./b2
-
Wait ~8 hours
sudo ./bjam cxxflags=-fPIC cflags=-fPIC -a install
-
Wait ~4 hours
-
From here, follow the general Raspberry Pi instructions from the "Clone scala and checkout most recent release version" step.
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 Shellshortcut -
Update packages using pacman:
pacman -Syu
-
Exit the MSYS shell using Alt+F4
-
Edit the properties for the
MSYS2 Shellshortcut 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 -Syu
-
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 mingw-w64-x86_64-openssl mingw-w64-x86_64-zeromq mingw-w64-x86_64-libsodium mingw-w64-x86_64-hidapi
To build for 32-bit Windows:
pacman -S mingw-w64-i686-toolchain make mingw-w64-i686-cmake mingw-w64-i686-boost mingw-w64-i686-openssl mingw-w64-i686-zeromq mingw-w64-i686-libsodium mingw-w64-i686-hidapi
-
Open the MingW shell via
MinGW-w64-Win64 Shellshortcut on 64-bit Windows orMinGW-w64-Win64 Shellshortcut on 32-bit Windows. Note that if you are running 64-bit Windows, you will have both 64-bit and 32-bit MinGW shells.
Cloning
-
To git clone, run:
git clone --recursive https://github.com/scala-network/scala.git
Building
-
Change to the cloned directory, run:
cd scala -
If you would like a specific version/tag, do a git checkout for that version. eg. 'v0.15.0.0'. If you don't care about the version and just want binaries from master, skip this step:
git checkout v0.15.0.0
-
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 -
Optional: to build Windows binaries suitable for debugging on a 64-bit system, run:
make debug-static-win64
-
Optional: to build Windows binaries suitable for debugging on a 32-bit system, run:
make debug-static-win32
-
The resulting executables can be found in
build/debug/bin
The project can be built from scratch by following instructions for Linux above(but use gmake instead of make).
If you are running scala in a jail, you need to add sysvsem="new" to your jail configuration, otherwise lmdb will throw the error message: Failed to open lmdb environment: Function not implemented.
Scala is also available as a port or package as 'scala-cli`.
You will need to add a few packages to your system. pkg_add cmake gmake zeromq libiconv boost.
The doxygen and graphviz packages are optional and require the xbase set.
Running the test suite also requires py-requests package.
Build scala: env DEVELOPER_LOCAL_TOOLS=1 BOOST_ROOT=/usr/local gmake release-static
Note: you may encounter the following error, when compiling the latest version of scala as a normal user:
LLVM ERROR: out of memory
c++: error: unable to execute command: Abort trap (core dumped)
Then you need to increase the data ulimit size to 2GB and try again: ulimit -d 2000000
The default Solaris linker can't be used, you have to install GNU ld, then run cmake manually with the path to your copy of GNU ld:
mkdir -p build/release
cd build/release
cmake -DCMAKE_LINKER=/path/to/ld -D CMAKE_BUILD_TYPE=Release ../..
cd ../..Then you can run make as usual.
# Build image (for ARM 32-bit)
docker build -f utils/build_scripts/android32.Dockerfile -t scala-android .
# Build image (for ARM 64-bit)
docker build -f utils/build_scripts/android64.Dockerfile -t scala-android .
# Create container
docker create -it --name scala-android scala-android bash
# Get binaries
docker cp scala-android:/src/build/release/bin .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-linux-x86_64builds binaries on Linux on x86_64 portable across POSIX systems on x86_64 processorsmake release-static-linux-i686builds binaries on Linux on x86_64 or i686 portable across POSIX systems on i686 processorsmake release-static-linux-armv8builds binaries on Linux portable across POSIX systems on armv8 processorsmake release-static-linux-armv7builds binaries on Linux portable across POSIX systems on armv7 processorsmake release-static-linux-armv6builds binaries on Linux portable across POSIX systems on armv6 processorsmake release-static-win64builds binaries on 64-bit Windows portable across 64-bit Windows systemsmake release-static-win32builds binaries on 64-bit or 32-bit Windows portable across 32-bit Windows systems
You can also cross-compile static binaries on Linux for Windows and macOS with the depends system.
make depends target=x86_64-linux-gnufor 64-bit linux binaries.make depends target=x86_64-w64-mingw32for 64-bit windows binaries.- Requires:
python3 g++-mingw-w64-x86-64 wine1.6 bc
- Requires:
make depends target=x86_64-apple-darwin11for macOS binaries.- Requires:
cmake imagemagick libcap-dev librsvg2-bin libz-dev libbz2-dev libtiff-tools python-dev
- Requires:
make depends target=i686-linux-gnufor 32-bit linux binaries.- Requires:
g++-multilib bc
- Requires:
make depends target=i686-w64-mingw32for 32-bit windows binaries.- Requires:
python3 g++-mingw-w64-i686
- Requires:
make depends target=arm-linux-gnueabihffor armv7 binaries.- Requires:
g++-arm-linux-gnueabihf
- Requires:
make depends target=aarch64-linux-gnufor armv8 binaries.- Requires:
g++-aarch64-linux-gnu
- Requires:
make depends target=riscv64-linux-gnufor RISC V 64 bit binaries.- Requires:
g++-riscv64-linux-gnu
- Requires:
make depends target=x86_64-unknown-freebsdfor freebsd binaries.- Requires:
clang-8
- Requires:
make depends target=arm-linux-androidfor 32bit android binariesmake depends target=aarch64-linux-androidfor 64bit android binaries
The required packages are the names for each toolchain on apt. Depending on your distro, they may have different names.
Using depends might also be easier to compile Scala on Windows than using MSYS. Activate Windows Subsystem for Linux (WSL) with a distro (for example Ubuntu), install the apt build-essentials and follow the depends steps as depicted above.
The produced binaries still link libc dynamically. If the binary is compiled on a current distribution, it might not run on an older distribution with an older installation of libc. Passing -DBACKCOMPAT=ON to cmake will make sure that the binary will run on systems having at least libc version 2.17.
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/scaladTo list all available options, run ./bin/scalad --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/scalad --log-file scalad.log --detachTo run as a systemd service, copy
scalad.service to /etc/systemd/system/ and
scalad.conf to /etc/. The example
service assumes that the user scala 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
scala-wallet-cli, and possibly scalad, if you get crashes refreshing.
See README.i18n.md.
There is a new, still experimental, integration with Tor. The feature allows connecting over IPv4 and Tor simulatenously - IPv4 is used for relaying blocks and relaying transactions received by peers whereas Tor is used solely for relaying transactions received over local RPC. This provides privacy and better protection against surrounding node (sybil) attacks.
While Scala isn't made to integrate with Tor, it can be used wrapped with torsocks, by setting the following configuration parameters and environment variables:
--p2p-bind-ip 127.0.0.1on the command line orp2p-bind-ip=127.0.0.1in scalad.conf to disable listening for connections on external interfaces.--no-igdon the command line orno-igd=1in scalad.conf to disable IGD (UPnP port forwarding negotiation), which is pointless with Tor.DNS_PUBLIC=tcporDNS_PUBLIC=tcp://x.x.x.xwhere x.x.x.x is the IP of the desired DNS server, for DNS requests to go over TCP, so that they are routed through Tor. When IP is not specified, scalad uses the default list of servers defined in src/common/dns_utils.cpp.TORSOCKS_ALLOW_INBOUND=1to tell torsocks to allow scalad to bind to interfaces to accept connections from the wallet. On some Linux systems, torsocks allows binding to localhost by default, so setting this variable is only necessary to allow binding to local LAN/VPN interfaces to allow wallets to connect from remote hosts. On other systems, it may be needed for local wallets as well.- Do NOT pass
--detachwhen running through torsocks with systemd, (see utils/systemd/scalad.service for details). - If you use the wallet with a Tor daemon via the loopback IP (eg, 127.0.0.1:9050),
then use
--untrusted-daemonunless it is your own hidden service.
Example command line to start scalad through Tor:
DNS_PUBLIC=tcp torsocks scalad --p2p-bind-ip 127.0.0.1 --no-igdTAILS 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 18081 -j ACCEPT
DNS_PUBLIC=tcp torsocks ./scalad --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/blockchainThis section contains general instructions for debugging failed installs or problems encountered with Scala. First, ensure you are running the latest version built from the Github repo.
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
gdbin 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/scalad `pidof scalad`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
Enter echo core | sudo tee /proc/sys/kernel/core_pattern to stop cores from being hijacked by other tools
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 scalad. It may be named just core, or core.xxxx with numbers appended.
You can now analyse this core dump with gdb as follows:
gdb /path/to/scalad /path/to/dumpfile`Print the stack trace with bt
- If a program crashed and cores are managed by systemd, the following can also get a stack trace for that crash:
coredumpctl -1 gdbType gdb /path/to/scalad
Pass command-line options with --args followed by the relevant arguments
Type run to run scalad
There are two tools available:
Configure Scala with the -D SANITIZE=ON cmake flag, eg:
cd build/debug && cmake -D SANITIZE=ON -D CMAKE_BUILD_TYPE=Debug ../..You can then run the scala tools normally. Performance will typically halve.
Install valgrind and run as valgrind /path/to/scalad. It will be very slow.
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 ~/scala/external/db_drivers/liblmdb && makeThe 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.
Because of the nature of the socket-based protocols that drive scala, certain protocol weaknesses are somewhat unavoidable at this time. While these weaknesses can theoretically be fully mitigated, the effort required (the means) may not justify the ends. As such, please consider taking the following precautions if you are a scala node operator:
- Run
scaladon a "secured" machine. If operational security is not your forte, at a very minimum, have a dedicated a computer runningscaladand do not browse the web, use email clients, or use any other potentially harmful apps on yourscaladmachine. Do not click links or load URL/MUA content on the same machine. Doing so may potentially exploit weaknesses in commands which accept "localhost" and "127.0.0.1". - If you plan on hosting a public "remote" node, start
scaladwith--restricted-rpc. This is a must.
Certain blockchain "features" can be considered "bugs" if misused correctly. Consequently, please consider the following:
- When receiving scala, be aware that it may be locked for an arbitrary time if the sender elected to, preventing you from spending that scala until the lock time expires. You may want to hold off acting upon such a transaction until the unlock time lapses. To get a sense of that time, you can consider the remaining blocktime until unlock as seen in the
show_transferscommand.
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