Credits (CRDS) v1.4.0.0

Copyright (c) 2017-2019 Credits Developers

What is Credits?

• Coin Suffix: CRDS
• PoW Mining Algorithm: Argon2d
• PoW Difficulty Algorithm: DELTA
• PoW Target Spacing: 128 Seconds
• PoW Reward per Block: See Below
• Maturity: 10 Blocks
• PoW Blocks: ~675 per day
• Masternode Collateral Amount: 5,000 CRDS
• Masternode Min Confirmation: 16 Blocks
• Masternode Reward: See Below
• Total Coins (until 2 PoW / 2 MN reward): 18,987,500* (~6 Years)
• Min TX Fee: 0.0001 CRDS

*Until block 375,000 all transaction fees get burned.

Credits uses peer-to-peer technology to operate securly with no central authority (decentralisation): managing transactions and issuing currency (CRDS) are carried out collectively by the Credits network. Credits is the name of open source software which enables the use of the currency CRDS.

Credits utilises Masternodes, Privatesend and InstantSend to provide anonymous and near instant transaction confirmations.

Credits implements Gavin Andresens signature cache optimisation from Bitcoin for significantly faster transaction validation.

Masternode/Privatesend Network Information Utilisation of InstantSend for near-instant transactions and PrivateSend for anonymous transactions.

MainNet Parameters P2P Port = 31000 RPC Port = 31050 Masternodes = 31000 Magic Bytes: 0x2f 0x32 0x45 0x51

TestNet Parameters P2P Port = 31400 RPC Port = 31450 Masternodes = 31400 Magic Bytes: 0x1f 0x22 0x05 0x30

RegTest Parameters P2P Port = 31500 RPC Port = 31550 Masternodes = 31500 Magic Bytes = 0x1f 0x22 0x05 0x2f

Rewards Structure

UNIX BUILD NOTES

Some notes on how to build Credits in Unix.

Note

Always use absolute paths to configure and compile Credits and the dependencies, for example, when specifying the the path of the dependency:

../dist/configure --enable-cxx --disable-shared --with-pic --prefix=$BDB_PREFIX

Here BDB_PREFIX must absolute path - it is defined using $(pwd) which ensures the usage of the absolute path.

To Build

./autogen.sh
./configure
make
make install # optional

This will build credits-qt as well if the dependencies are met.

Dependencies

These dependencies are required:

Optional dependencies:

For the versions used in the release, see release-process.md under Fetch and build inputs.

System requirements

C++ compilers are memory-hungry. It is recommended to have at least 3 GB of memory available when compiling Credits.

Dependency Build Instructions: Ubuntu & Debian

Build requirements:

sudo apt-get install build-essential libtool automake autotools-dev autoconf pkg-config libssl-dev libcrypto++-dev libevent-dev git

for Ubuntu 12.04 and later or Debian 7 and later libboost-all-dev has to be installed:

sudo apt-get install libboost-all-dev

db4.8 packages are available here. You can add the repository using the following command:

    sudo add-apt-repository ppa:bitcoin/bitcoin
    sudo apt-get update

Ubuntu 12.04 and later have packages for libdb5.1-dev and libdb5.1++-dev, but using these will break binary wallet compatibility, and is not recommended.

for Debian 7 (Wheezy) and later: The oldstable repository contains db4.8 packages. Add the following line to /etc/apt/sources.list, replacing [mirror] with any official debian mirror.

deb http://[mirror]/debian/ oldstable main

To enable the change run

sudo apt-get update

for other Debian & Ubuntu (with ppa):

sudo apt-get install libdb4.8-dev libdb4.8++-dev

Optional (see --with-miniupnpc and --enable-upnp-default):

sudo apt-get install libminiupnpc-dev

ZMQ dependencies (provides ZMQ API 4.x):

    sudo apt-get install libzmq3-dev

Dependencies for the GUI: Ubuntu & Debian

If you want to build Credits-Qt, make sure that the required packages for Qt development are installed. Qt 5 is necessary to build the GUI. If both Qt 4 and Qt 5 are installed, Qt 5 will be used. Pass --with-gui=qt5 to configure to choose Qt5. To build without GUI pass --without-gui.

For Qt 5 you need the following:

sudo apt-get install libqt5gui5 libqt5core5a libqt5dbus5 qttools5-dev qttools5-dev-tools libprotobuf-dev protobuf-compiler libcrypto++-dev

libqrencode (optional) can be installed with:

sudo apt-get install libqrencode-dev

Once these are installed, they will be found by configure and a credits-qt executable will be built by default.

Notes

The release is built with GCC and then "strip creditsd" to strip the debug symbols, which reduces the executable size by about 90%.

miniupnpc

miniupnpc may be used for UPnP port mapping. It can be downloaded from here. UPnP support is compiled in and turned off by default. See the configure options for upnp behavior desired:

--without-miniupnpc      No UPnP support miniupnp not required
--disable-upnp-default   (the default) UPnP support turned off by default at runtime
--enable-upnp-default    UPnP support turned on by default at runtime

To build:

tar -xzvf miniupnpc-1.6.tar.gz
cd miniupnpc-1.6
make
sudo su
make install

Berkeley DB

It is recommended to use Berkeley DB 4.8. If you have to build it yourself:

CREDITS_ROOT=$(pwd)

# Pick some path to install BDB to, here we create a directory within the credits directory
BDB_PREFIX="${CREDITS_ROOT}/db4"
mkdir -p $BDB_PREFIX

# Fetch the source and verify that it is not tampered with
wget 'http://download.oracle.com/berkeley-db/db-4.8.30.NC.tar.gz'
echo '12edc0df75bf9abd7f82f821795bcee50f42cb2e5f76a6a281b85732798364ef  db-4.8.30.NC.tar.gz' | sha256sum -c
# -> db-4.8.30.NC.tar.gz: OK
tar -xzvf db-4.8.30.NC.tar.gz

# Build the library and install to our prefix
cd db-4.8.30.NC/build_unix/
#  Note: Do a static build so that it can be embedded into the exectuable, instead of having to find a .so at runtime
../dist/configure --prefix=/usr/local --enable-cxx
make
sudo make install

# Configure Credits to use our own-built instance of BDB
cd $CREDITS_ROOT
./configure (other args...) LDFLAGS="-L${BDB_PREFIX}/lib/" CPPFLAGS="-I${BDB_PREFIX}/include/"

Note: You only need Berkeley DB if the wallet is enabled (see the section Disable-Wallet mode below).

Boost

If you need to build Boost yourself:

sudo su
./bootstrap.sh
./bjam install

Security

To help make your Credits installation more secure by making certain attacks impossible to exploit even if a vulnerability is found, binaries are hardened by default. This can be disabled with:

Hardening Flags:

./configure --enable-hardening
./configure --disable-hardening

Hardening enables the following features:

• Position Independent Executable Build position independent code to take advantage of Address Space Layout Randomization offered by some kernels. An attacker who is able to cause execution of code at an arbitrary memory location is thwarted if he doesn't know where anything useful is located. The stack and heap are randomly located by default but this allows the code section to be randomly located as well.

  On an Amd64 processor where a library was not compiled with -fPIC, this will cause an error such as: "relocation R_X86_64_32 against `......' can not be used when making a shared object;"

  To test that you have built PIE executable, install scanelf, part of paxutils, and use:

  scanelf -e ./creditsd

  The output should contain: TYPE ET_DYN

• Non-executable Stack If the stack is executable then trivial stack based buffer overflow exploits are possible if vulnerable buffers are found. By default, credits should be built with a non-executable stack but if one of the libraries it uses asks for an executable stack or someone makes a mistake and uses a compiler extension which requires an executable stack, it will silently build an executable without the non-executable stack protection.

  To verify that the stack is non-executable after compiling use: scanelf -e ./creditsd

  the output should contain: STK/REL/PTL RW- R-- RW-

  The STK RW- means that the stack is readable and writeable but not executable.

Disable-wallet mode

When the intention is to run only a P2P node without a wallet, credits may be compiled in disable-wallet mode with:

./configure --disable-wallet

In this case there is no dependency on Berkeley DB 4.8.

Mining is also possible in disable-wallet mode, but only using the getblocktemplate RPC call.

AVX2 Mining Optimisations

For increased performance when mining, AVX2 optimisations can be enabled.

Prior to running the build commands:

CPPFLAGS=-march=native

CPU's with AVX2 support:

Intel
    Haswell processor, Q2 2013
    Haswell E processor, Q3 2014
    Broadwell processor, Q4 2014
    Broadwell E processor, Q3 2016
    Skylake processor, Q3 2015
    Kaby Lake processor, Q3 2016(ULV mobile)/Q1 2017(desktop/mobile)
    Coffee Lake processor, expected in 2017
    Cannonlake processor, expected in 2017
AMD
    Carrizo processor, Q2 2015
    Ryzen processor, Q1 2017

AVX512F Mining Optimisations

For increased performance when mining, AVX512F optimisations can be enabled.

At configure time:

--enable-avx512f

CPU's with AVX512F support:

Intel
    Xeon Phi x200/Knights Landing processor, 2016
    Knights Mill processor, 2017
    Skylake-SP processor, 2017
    Skylake-X processor, 2017
    Cannonlake processor, expected in 2018
    Ice Lake processor, expected in 2018

Example Build Command

Qt Wallet and Deamon, CLI version build:

./autogen.sh && ./configure --with-gui && make

CLI and Deamon Only Buld:

./autogen.sh && ./configure --without-gui && make