Copyright (c) 2016-2019 Duality Blockchain Solutions
What is Sequence?
- Coin Suffix: SEQ
- PoW Algorithm: Scrypt
- PoW Period: 10,000 Blocks
- PoW Target Spacing: 60 Seconds
- PoW Difficulty Retarget: 10 Blocks
- PoW Reward per Block: 0 SEQ
- Full Confirmation: 10 Blocks
- PoS Algorithm: Blake2b
- PoS Target Spacing: 64 Seconds
- PoS Difficulty Retarget: 10 Blocks
- PoS Reward: 2 SEQ
- PoS Min: 1 Hour
- PoS Max: Unlimited
- Total Coins: 263 - 1
- Block Size: 4MB
- Min TX Fee: 0.001 SEQ
Sequence(SEQ) was developed to provide data redundancy for the BDAP protocol and support the applications created by Duality & third-party developers. Sequence nodes implement static Proof-of-Stake (PoS) rewards in exchange for supporting the BDAP protocol, applications, blockchain and network.
Sequence(SEQ) is a digital currency that enables instant payments to anyone, anywhere in the world. Sequence(SEQ) uses peer-to-peer technology to operate with no central authority (decentralisation): managing transactions and issuing currency (SEQ) are carried out collectively by the Sequence network. Sequence is the name of open source software which enables the use of the currency SEQ.
MainNet Parameters P2P Port = 16662 RPC Port = 16663
TestNet Parameters P2P Port = 16664 RPC Port = 16665
Some notes on how to build Sequence in Unix.
Building requirements for Unix based Systems : 3GB
Always use absolute paths to configure and compile Sequence 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.
./autogen.sh
./configure
make
make install # optionalThis will build sequence-qt as well if the dependencies are met.
These dependencies are required:
| Library | Purpose | Description |
|---|---|---|
| libssl | SSL Support | Secure communications |
| libboost | Boost | C++ Library |
Optional dependencies:
| Library | Purpose | Description |
|---|---|---|
| miniupnpc | UPnP Support | Firewall-jumping support |
| libdb4.8 | Berkeley DB | Wallet storage (only needed when wallet enabled) |
| qt | GUI | GUI toolkit (only needed when GUI enabled) |
| protobuf | Payments in GUI | Data interchange format used for payment protocol (only needed when GUI enabled) |
| libqrencode | QR codes in GUI | Optional for generating QR codes (only needed when GUI enabled) |
For the versions used in the release, see release-process.md under Fetch and build inputs.
C++ compilers are memory-hungry. It is recommended to have at least 1 GB of memory available when compiling Sequence. With 512MB of memory or less compilation will take much longer due to swap thrashing.
Build requirements:
sudo apt-get install git build-essential libtool autotools-dev autoconf pkg-config libssl-dev libcrypto++-dev libevent-dev
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:
sudo apt-get install libminiupnpc-dev (see --with-miniupnpc and --enable-upnp-default)
If you want to build Sequence-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 sequence-qt executable will be built by default.
The release is built with GCC and then "strip sequenced" to strip the debug symbols, which reduces the executable size by about 90%.
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
It is recommended to use Berkeley DB 4.8. If you have to build it yourself:
SEQUENCE_ROOT=$(pwd)
# Pick some path to install BDB to, here we create a directory within the sequence directory
BDB_PREFIX="${SEQUENCE_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 Sequence to use our own-built instance of BDB
cd $SEQUENCE_ROOT
./configure (other args...) LDFLAGS="-L${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).
If you need to build Boost yourself:
sudo su
./bootstrap.sh
./bjam install
To help make your Sequence 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 ./sequencedThe 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, sequence 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 ./sequencedthe output should contain: STK/REL/PTL RW- R-- RW-
The STK RW- means that the stack is readable and writeable but not executable.
When the intention is to run only a P2P node without a wallet, sequence 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 not getwork.
Qt Wallet and Deamon, CLI version build:
./autogen.sh && ./configure --with-gui=qt5 && make
CLI and Deamon Only Buld:
./autogen.sh && ./configure --without-gui && make