wCoin

A free OpenSource-P2P-Crypto money for you.

Current project status: not building, we need servers

We are based on CryptoNote cryptocurrency protocol.

• Launch your own CryptoNote currency: CryptoNote Starter
• CryptoNote reference implementation: CryptoNoteCoin
• Discussion board and support: CryptoNote Forum

wCoin forking how-to

Preparation

1. Create an account on GitHub.com
2. Fork CryptoNote repository
3. Buy one or two Ubuntu-based dedicated servers (at least 2Gb of RAM) for seed nodes.

First step. Give a name to your coin

Good name must be unique. Check uniqueness with google and Map of Coins or any other similar service.

Name must be specified twice:

1. in file src/CryptoNoteConfig.h - CRYPTONOTE_NAME constant

Example:

const char CRYPTONOTE_NAME[] = "furiouscoin";

2. in src/CMakeList.txt file - set_property(TARGET daemon PROPERTY OUTPUT_NAME "YOURCOINNAMEd")

Example:

set_property(TARGET daemon PROPERTY OUTPUT_NAME "wcoind")

Note: You should also change a repository name.

Second step. Emission logic

1. Total money supply (src/CryptoNoteConfig.h)

Total amount of coins to be emitted. Most of CryptoNote based coins use (uint64_t)(-1) (equals to 18446744073709551616). You can define number explicitly (for example UINT64_C(858986905600000000)).

Example:

const uint64_t MONEY_SUPPLY = (uint64_t)(-1);

2. Emission curve (src/CryptoNoteConfig.h)

Be default CryptoNote provides emission formula with slight decrease of block reward with each block. This is different from Bitcoin where block reward halves every 4 years.

EMISSION_SPEED_FACTOR constant defines emission curve slope. This parameter is required to calulate block reward.

Example:

const unsigned EMISSION_SPEED_FACTOR = 18;

3. Difficulty target (src/CryptoNoteConfig.h)

Difficulty target is an ideal time period between blocks. In case an average time between blocks becomes less than difficulty target, the difficulty increases. Difficulty target is measured in seconds.

Difficulty target directly influences several aspects of coin's behavior:

• transaction confirmation speed: the longer the time between the blocks is, the slower transaction confirmation is
• emission speed: the longer the time between the blocks is the slower the emission process is
• orphan rate: chains with very fast blocks have greater orphan rate

For most coins difficulty target is 60 or 120 seconds.

Example:

const uint64_t DIFFICULTY_TARGET = 120;

4. Block reward formula

In case you are not satisfied with CryptoNote default implementation of block reward logic you can also change it. The implementation is in src/CryptoNoteCore/Currency.cpp:

bool Currency::getBlockReward(size_t medianSize, size_t currentBlockSize, uint64_t alreadyGeneratedCoins, uint64_t fee, uint64_t& reward, int64_t& emissionChange) const

This function has two parts:

• basic block reward calculation: uint64_t baseReward = (m_moneySupply - alreadyGeneratedCoins) >> m_emissionSpeedFactor;
• big block penalty calculation: this is the way CryptoNote protects the block chain from transaction flooding attacks and preserves opportunities for organic network growth at the same time.

Only the first part of this function is directly related to the emission logic. You can change it the way you want. See MonetaVerde and DuckNote as the examples where this function is modified.

Third step. Networking

1. Default ports for P2P and RPC networking (src/CryptoNoteConfig.h)

P2P port is used by daemons to talk to each other through P2P protocol. RPC port is used by wallet and other programs to talk to daemon.

It's better to choose ports that aren't used by other software or coins. See known TCP ports lists:

• http://www.speedguide.net/ports.php
• http://www.networksorcery.com/enp/protocol/ip/ports00000.htm
• http://keir.net/portlist.html

Example:

const int P2P_DEFAULT_PORT = 17236;
const int RPC_DEFAULT_PORT = 18236;

2. Network identifier (src/P2p/P2pNetworks.h)

This identifier is used in network packages in order not to mix two different cryptocoin networks. Change all the bytes to random values for your network:

const static boost::uuids::uuid CRYPTONOTE_NETWORK = { { 0xA1, 0x1A, 0xA1, 0x1A, 0xA1, 0x0A, 0xA1, 0x0A, 0xA0, 0x1A, 0xA0, 0x1A, 0xA0, 0x1A, 0xA1, 0x1A } };

3. Seed nodes (src/CryptoNoteConfig.h)

Add IP addresses of your seed nodes.

Example:

const std::initializer_list<const char*> SEED_NODES = {
  "111.11.11.11:17236",
  "222.22.22.22:17236",
};

Fourth step. Transaction fee and related parameters

1. Minimum transaction fee (src/CryptoNoteConfig.h)

Zero minimum fee can lead to transaction flooding. Transactions cheaper than the minimum transaction fee wouldn't be accepted by daemons. 100000 value for MINIMUM_FEE is usually enough.

Example:

const uint64_t MINIMUM_FEE = 100000;

2. Penalty free block size (src/CryptoNoteConfig.h)

CryptoNote protects chain from tx flooding by reducing block reward for blocks larger than the median block size. However, this rule applies for blocks larger than CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE bytes.

Example:

const size_t CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE = 20000;

Fifth step. Address prefix

You may choose a letter (in some cases several letters) all the coin's public addresses will start with. It is defined by CRYPTONOTE_PUBLIC_ADDRESS_BASE58_PREFIX constant. Since the rules for address prefixes are nontrivial you may use the prefix generator tool.

Example:

const uint64_t CRYPTONOTE_PUBLIC_ADDRESS_BASE58_PREFIX = 0xe9; // addresses start with "f"

Sixth step. Genesis block

1. Build the binaries with blank genesis tx hex (src/CryptoNoteConfig.h)

You should leave const char GENESIS_COINBASE_TX_HEX[] blank and compile the binaries without it.

Example:

const char GENESIS_COINBASE_TX_HEX[] = "";

2. Start the daemon to print out the genesis block

Run your daemon with --print-genesis-tx argument. It will print out the genesis block coinbase transaction hash.

Example:

wcoind --print-genesis-tx

3. Copy the printed transaction hash (src/CryptoNoteConfig.h)

Copy the tx hash that has been printed by the daemon to GENESIS_COINBASE_TX_HEX in src/CryptoNoteConfig.h

Example:

const char GENESIS_COINBASE_TX_HEX[] = "013c01ff0001ffff...785a33d9ebdba68b0";

4. Recompile the binaries

Recompile everything again. Your coin code is ready now. Make an announcement for the potential users and enjoy!

Building CryptoNote

On *nix

Dependencies: GCC 4.7.3 or later, CMake 2.8.6 or later, and Boost 1.55.

You may download them from:

• http://gcc.gnu.org/
• http://www.cmake.org/
• http://www.boost.org/
• Alternatively, it may be possible to install them using a package manager.

To build, change to a directory where this file is located, and run make. The resulting executables can be found in build/release/src.

Advanced options:

• Parallel build: run make -j<number of threads> instead of make.
• Debug build: run make build-debug.
• Test suite: run make test-release to run tests in addition to building. Running make test-debug will do the same to the debug version.
• Building with Clang: it may be possible to use Clang instead of GCC, but this may not work everywhere. To build, run export CC=clang CXX=clang++ before running make.

On Windows

Dependencies: MSVC 2013 or later, CMake 2.8.6 or later, and Boost 1.55. You may download them from:

• http://www.microsoft.com/
• http://www.cmake.org/
• http://www.boost.org/

To build, change to a directory where this file is located, and run theas commands:

mkdir build
cd build
cmake -G "Visual Studio 12 Win64" ..

And then do Build. Good luck!