All smart contracts which we have considered earlier belonged and were executed by accounts of real people. However, we can’t exclude the operation of robots in Yocoin ecosystem. Such contracts can create the same actions as well as any account of the real person. Contracts can own coins, participate in crowd sales, and participate in the voting process.
Our task is to create the decentralized organization having the democratic principles. This organization is realized with the help a blockchain of technology and can carry out the same functions, as another account. By default, the organization has the central leader who makes decisions who is a member of the organization and regulates rules of the vote. But in our case, we will show as it can be sent.
We will deal with that as it has to work. The essence of the organization consists that she has an Owner who carries out a role of the administrator, president or CEO. The owner can give the right of the vote of any members of the organization. At the same time, any member of the organization is capable to make the proposal, in the form of transaction of You, or the offer on sending You or will suggest executing this or that contract. Other members of the organization “having the right to vote” can vote in support of this offer or against it. If during a certain amount of time a certain number of members of the organization has voted, this offer can be executed. The contract will count a number of votes and in case of their enough will execute the transaction.
The Blockchain organization
pragma solidity ^0.4.16;
contract owned {
address public owner;
function owned() public {
owner = msg.sender;
}
modifier onlyOwner {
require(msg.sender == owner);
_;
}
function transferOwnership(address newOwner) onlyOwner public {
owner = newOwner;
}
}
contract tokenRecipient {
event receivedEther(address sender, uint amount);
event receivedTokens(address _from, uint256 _value, address _token, bytes _extraData);
function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) public {
Token t = Token(_token);
require(t.transferFrom(_from, this, _value));
receivedTokens(_from, _value, _token, _extraData);
}
function () payable public {
receivedEther(msg.sender, msg.value);
}
}
interface Token {
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
}
contract Congress is owned, tokenRecipient {
// Contract Variables and events
uint public minimumQuorum;
uint public debatingPeriodInMinutes;
int public majorityMargin;
Proposal[] public proposals;
uint public numProposals;
mapping (address => uint) public memberId;
Member[] public members;
event ProposalAdded(uint proposalID, address recipient, uint amount, string description);
event Voted(uint proposalID, bool position, address voter, string justification);
event ProposalTallied(uint proposalID, int result, uint quorum, bool active);
event MembershipChanged(address member, bool isMember);
event ChangeOfRules(uint newMinimumQuorum, uint newDebatingPeriodInMinutes, int newMajorityMargin);
struct Proposal {
address recipient;
uint amount;
string description;
uint votingDeadline;
bool executed;
bool proposalPassed;
uint numberOfVotes;
int currentResult;
bytes32 proposalHash;
Vote[] votes;
mapping (address => bool) voted;
}
struct Member {
address member;
string name;
uint memberSince;
}
struct Vote {
bool inSupport;
address voter;
string justification;
}
// Modifier that allows only shareholders to vote and create new proposals
modifier onlyMembers {
require(memberId[msg.sender] != 0);
_;
}
/**
* Constructor function
*/
function Congress (
uint minimumQuorumForProposals,
uint minutesForDebate,
int marginOfVotesForMajority
) payable public {
changeVotingRules(minimumQuorumForProposals, minutesForDebate, marginOfVotesForMajority);
// It’s necessary to add an empty first member
addMember(0, "");
// and let's add the founder, to save a step later
addMember(owner, 'founder');
}
/**
* Add member
*
* Make `targetMember` a member named `memberName`
*
* @param targetMember YOCoin address to be added
* @param memberName public name for that member
*/
function addMember(address targetMember, string memberName) onlyOwner public {
uint id = memberId[targetMember];
if (id == 0) {
memberId[targetMember] = members.length;
id = members.length++;
}
members[id] = Member({member: targetMember, memberSince: now, name: memberName});
MembershipChanged(targetMember, true);
}
/**
* Remove member
*
* @notice Remove membership from `targetMember`
*
* @param targetMember YOCoin address to be removed
*/
function removeMember(address targetMember) onlyOwner public {
require(memberId[targetMember] != 0);
for (uint i = memberId[targetMember]; i<members.length-1; i++){
members[i] = members[i+1];
}
delete members[members.length-1];
members.length--;
}
/**
* Change voting rules
*
* Make so that proposals need to be discussed for at least `minutesForDebate/60` hours,
* have at least `minimumQuorumForProposals` votes, and have 50% + `marginOfVotesForMajority` votes to be executed
*
* @param minimumQuorumForProposals how many members must vote on a proposal for it to be executed
* @param minutesForDebate the minimum amount of delay between when a proposal is made and when it can be executed
* @param marginOfVotesForMajority the proposal needs to have 50% plus this number
*/
function changeVotingRules(
uint minimumQuorumForProposals,
uint minutesForDebate,
int marginOfVotesForMajority
) onlyOwner public {
minimumQuorum = minimumQuorumForProposals;
debatingPeriodInMinutes = minutesForDebate;
majorityMargin = marginOfVotesForMajority;
ChangeOfRules(minimumQuorum, debatingPeriodInMinutes, majorityMargin);
}
/**
* Add Proposal
*
* Propose to send `weiAmount / 1e18` ether to `beneficiary` for `jobDescription`. `transactionBytecode ? Contains : Does not contain` code.
*
* @param beneficiary who to send the ether to
* @param weiAmount amount of ether to send, in wei
* @param jobDescription Description of job
* @param transactionBytecode bytecode of transaction
*/
function newProposal(
address beneficiary,
uint weiAmount,
string jobDescription,
bytes transactionBytecode
)
onlyMembers public
returns (uint proposalID)
{
proposalID = proposals.length++;
Proposal storage p = proposals[proposalID];
p.recipient = beneficiary;
p.amount = weiAmount;
p.description = jobDescription;
p.proposalHash = keccak256(beneficiary, weiAmount, transactionBytecode);
p.votingDeadline = now + debatingPeriodInMinutes * 1 minutes;
p.executed = false;
p.proposalPassed = false;
p.numberOfVotes = 0;
ProposalAdded(proposalID, beneficiary, weiAmount, jobDescription);
numProposals = proposalID+1;
return proposalID;
}
/**
* Add proposal in Ether
*
* Propose to send `etherAmount` ether to `beneficiary` for `jobDescription`. `transactionBytecode ? Contains : Does not contain` code.
* This is a convenience function to use if the amount to be given is in round number of ether units.
*
* @param beneficiary who to send the ether to
* @param etherAmount amount of ether to send
* @param jobDescription Description of job
* @param transactionBytecode bytecode of transaction
*/
function newProposalInEther(
address beneficiary,
uint etherAmount,
string jobDescription,
bytes transactionBytecode
)
onlyMembers public
returns (uint proposalID)
{
return newProposal(beneficiary, etherAmount * 1 ether, jobDescription, transactionBytecode);
}
/**
* Check if a proposal code matches
*
* @param proposalNumber ID number of the proposal to query
* @param beneficiary who to send the ether to
* @param weiAmount amount of ether to send
* @param transactionBytecode bytecode of transaction
*/
function checkProposalCode(
uint proposalNumber,
address beneficiary,
uint weiAmount,
bytes transactionBytecode
)
constant public
returns (bool codeChecksOut)
{
Proposal storage p = proposals[proposalNumber];
return p.proposalHash == keccak256(beneficiary, weiAmount, transactionBytecode);
}
/**
* Log a vote for a proposal
*
* Vote `supportsProposal? in support of : against` proposal #`proposalNumber`
*
* @param proposalNumber number of proposal
* @param supportsProposal either in favor or against it
* @param justificationText optional justification text
*/
function vote(
uint proposalNumber,
bool supportsProposal,
string justificationText
)
onlyMembers public
returns (uint voteID)
{
Proposal storage p = proposals[proposalNumber]; // Get the proposal
require(!p.voted[msg.sender]); // If has already voted, cancel
p.voted[msg.sender] = true; // Set this voter as having voted
p.numberOfVotes++; // Increase the number of votes
if (supportsProposal) { // If they support the proposal
p.currentResult++; // Increase score
} else { // If they don't
p.currentResult--; // Decrease the score
}
// Create a log of this event
Voted(proposalNumber, supportsProposal, msg.sender, justificationText);
return p.numberOfVotes;
}
/**
* Finish vote
*
* Count the votes proposal #`proposalNumber` and execute it if approved
*
* @param proposalNumber proposal number
* @param transactionBytecode optional: if the transaction contained a bytecode, you need to send it
*/
function executeProposal(uint proposalNumber, bytes transactionBytecode) public {
Proposal storage p = proposals[proposalNumber];
require(now > p.votingDeadline // If it is past the voting deadline
&& !p.executed // and it has not already been executed
&& p.proposalHash == keccak256(p.recipient, p.amount, transactionBytecode) // and the supplied code matches the proposal
&& p.numberOfVotes >= minimumQuorum); // and a minimum quorum has been reached...
// ...then execute result
if (p.currentResult > majorityMargin) {
// Proposal passed; execute the transaction
p.executed = true; // Avoid recursive calling
require(p.recipient.call.value(p.amount)(transactionBytecode));
p.proposalPassed = true;
} else {
// Proposal failed
p.proposalPassed = false;
}
// Fire Events
ProposalTallied(proposalNumber, p.currentResult, p.numberOfVotes, p.proposalPassed);
}
}
HOW TO DEPLOY
Open the wallet (if you are only testing, go to the menu develop > network > testnet), go to the Contracts tab and then press deploy contract, and on the solidity code box, paste the code above. On the contract picker, choose Congress and you’ll see the setup variables.
- Minimum quorum for proposals is the minimum amount of votes a proposal needs to have before it can be executed.
- Minutes for debate is the minimum amount of time (in minutes) that needs to pass before it can be executed.
- Margin of votes for majority. A proposal passes if there are more than 50% of the votes plus the margin. Leave at 0 for simple majority, put it at the number of members – 1 to require an absolute consensus.
Later you will have an opportunity to change these parameters. For a start, you can expose the parameter of 5 min. on the voting, other parameters to equate to 0. You can look at the cost of the expansion of your contract in You and you will find out that is lower on the page. At the same, time you have an opportunity to reduce the expansion price, but at the same time of execution of this contract will be increased. Press deploy, enter the password and wait.
After a while to you the toolbar will open, having scrolled down you will see as your transaction is created. Still, after a while, you will see the confirmed transaction and for it, the unique badge will be created. Having pressed the name of the contract, you will be able to see him. At the same time, it will be always available in the Contracts tab.
SHARING WITH THE OTHERS
If you want to share your DAO with others, then they need both the contract address and the interface file, a small text string that works as an instruction manual of the contract. Click copy address to get the former and show interface to reveal the latter.
On the other computer, go into the Contracts tab and then click on watch contract. Add the correct address and interface and press OK.
INTERACTING WITH THE CONTRACT
On the “Read from contract” you can see all the functions you can execute for free on the contract, as they are just reading information from the blockchain. Here you can see, for instance, the current “owner” of the contract (that should be the account that uploaded the contract).
On the “Write to contract” you have a list of all the functions that will attempt to do some computation that saves data to the blockchain, and therefore will cost YOC. Select “New Proposal” and it will show all the options for that function.
You need to add new members who could vote. On the “Select function” tab you will choose “Add Member“. Add the address of the person whom you want to make the member of the organization. Also, you can remove the participant by clicking “Remove Member”. You need to be convinced that you act on behalf of the same account, as the owner. It can be checked in “Execute from” since only the chief manager has a similar function. Press Execute and wait some time that the following block could make your change.
You have no opportunity to see all list of participants, however you can check membership of this or that participant, having inserted the address into the Members function in the Read from contract.
Except that your contract would have own money, you need to bring in it YOC or other token. For this purpose Press Transfer Yoc & Tokens on the top right corner.
ADD A SIMPLE PROPOSAL: SEND YOC.
Now let’s add the first proposal to the contract. On the function picker, select New Proposal.
For “beneficiary” add the address of someone you want to send YOC to, and put how much you want to send in the box marked “Wei Amount.” Wei is the smallest unit of YOC, equal to 10^-18 YOC, and must always be given as an integer. For example, if you want to send 1 YOC, enter 1000000000000000000 (that’s 18 zeroes). Finally, add some text describing the reason you want to do this. Leave “Transaction bytecode” blank for now. Click execute and type your password. After a few seconds the numProposals will increase to 1 and the first proposal, number 0, will appear on the left column. As you add more proposals, you can see any of them by simply putting the proposal number on the “proposals” field and you can read all about it.
Voting on a proposal is also very simple. Choose “Vote” on the function picker. Type the proposal Number in the first box and check the “Yes” box if you agree with it (or leave it blank to vote against it). Click “Execute” to send your vote.
When the voting time has passed, you can select “executeProposal”. If the proposal was simply sending YOC, then you can also leave the “transactionBytecode” field blank. After pressing “execute” but before typing your password, pay attention to the screen that appears.
If there is a warning on the “estimated fee consumption” field, then this means that for some reason the function called will not execute and will be abruptly terminated. It can mean many things, but in the context of this contract this warning will show up whenever you try to execute a contract before its deadline has passed, or if the user is trying to send a different bytecode data than the original proposal had. For security reasons if any of these things happens, the contract execution is abruptly terminated and the user that attempted the illegal transaction will lose all the yocs he sent to pay transaction fees.
If the transaction was executed, then after a few seconds you should be able to see the result: executed will turn to true and the correct amount of YOC should be subtracted from this contract’s balance and into the recipient address.
ADD A COMPLEX PROPOSAL: OWN ANOTHER TOKEN
You can use this democracy to execute any transaction on Yocoin, as long as you can figure out the bytecode that transaction generates. Luckily for us, you can use the wallet to do precisely that!
In this example, we’ll use a token to show that this contract can hold more than yoc and can do transactions in any other yocoin-based asset. First, create a tokenthat belongs to one of your normal accounts. On the contract page, click Transfer Yoc & Tokens to transfer some of them to your new congress contract (for simplicity, don’t send more than half your coins to your DAO). After that, we are going to simulate the action you want to execute. So, if you want to propose that the DAO send 500mg of a gold token to a person as a payment, then follow the steps that you’d do to execute that transaction from an account you own and press “send” but when the confirmation screens pops up, don’t type your password.
Instead, click “SHOW RAW DATA” link and copy the code displayed on the “RAW DATA” field and save it to a text file or notepad. Cancel the transaction. You’ll also need the address of the contract you’ll be calling for that operation, in this case the token contract. You can find it on the Contracts tab: save that somewhere too.
Now go back to the congress contract and create a new proposal with these parameters:
- As the beneficiary, put the address of your token (pay attention if it’s the same icon)
- Leave Yoc amount blank
- On the Job description just write a small description on what you want to accomplish
- On the Transaction Bytecode, paste the bytecode you saved from the data field on the previous step
In a few seconds you should be able to see the details of the proposal. You’ll notice that the transaction bytecode won’t be shown there. There’s only a “transaction hash” instead. Unlike the other fields, Bytecode can be extremely lengthy and therefore expensive to store on the blockchain, so instead of archiving it, the person executing the call later will provide the bytecode.
That creates a security hole: how can a proposal be voted without the actual code being there? And what prevents a user from executing a different code after the proposal has been voted on? That’s where transaction hash comes in. Scroll a bit the “read from contract” function list and you’ll see a proposal checker function, where anyone can put all the function parameters and check if they match the one being voted on. This also guarantees that proposals don’t get executed unless the hash of the bytecode matches exactly the one on the provided code.
Anyone can check the proposal easily by following the same steps to get the correct bytecode. Adding the proposal number and other parameters to the function called Check proposal code on the bottom of Read from contract.
The rest of the voting process remains the same. All the members can vote and after the deadline, someone can execute the proposal. The only difference is that this time you’ll have to provide the same bytecode you’ve submitted before. Pay attention to any warnings on the confirmation window. If it says it won’t execute your code, check to see if the deadline has already passed, if there are enough votes and if your transaction bytecode checks out.
MAKE IT BETTER
Here are some drawbacks of this current DAO that we leave an exercise to the reader:
- Can you make the member list public and indexed?
- Can you allow members to change their votes (after votes are cast but before the votes are tallied up)?
- Currently the vote message is only visible on logs. Can you make a function that displays all the votes?
The Shareholder Association
In the previous section we created a contract that works like an invitation. The only club, where members are invited or banned by the whim of the president. This has a few drawback. What if someone wants to change his main address? What if some members have more weight than others? What if you want to trade or sell memberships or shares on an open market? What if you wanted your organization to have work as a constant decision machine by shareholders?
We are going to modify our contract to connect it to a specific token, which will work as the holding shares of the contract. Firstly, we need to create this token: go to the token tutorial and create a simple token with initial supply of 100, decimals of 0 and a percentage sign (%) as a symbol. If you want to be able to trade in fractions of a percent, then increase the supply by 100x or 1000x and then add the corresponding number of zeros as the decimals. Deploy this contract and save its address on a text file.
Now to the shareholder code:
pragma solidity ^0.4.16;
contract owned {
address public owner;
function owned() {
owner = msg.sender;
}
modifier onlyOwner {
require(msg.sender == owner);
_;
}
function transferOwnership(address newOwner) onlyOwner {
owner = newOwner;
}
}
contract tokenRecipient {
event receivedEther(address sender, uint amount);
event receivedTokens(address _from, uint256 _value, address _token, bytes _extraData);
function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData){
Token t = Token(_token);
require(t.transferFrom(_from, this, _value));
receivedTokens(_from, _value, _token, _extraData);
}
function () payable {
receivedEther(msg.sender, msg.value);
}
}
contract Token {
mapping (address => uint256) public balanceOf;
function transferFrom(address _from, address _to, uint256 _value) returns (bool success);
}
/**
* The shareholder association contract itself
*/
contract Association is owned, tokenRecipient {
uint public minimumQuorum;
uint public debatingPeriodInMinutes;
Proposal[] public proposals;
uint public numProposals;
Token public sharesTokenAddress;
event ProposalAdded(uint proposalID, address recipient, uint amount, string description);
event Voted(uint proposalID, bool position, address voter);
event ProposalTallied(uint proposalID, uint result, uint quorum, bool active);
event ChangeOfRules(uint newMinimumQuorum, uint newDebatingPeriodInMinutes, address newSharesTokenAddress);
struct Proposal {
address recipient;
uint amount;
string description;
uint votingDeadline;
bool executed;
bool proposalPassed;
uint numberOfVotes;
bytes32 proposalHash;
Vote[] votes;
mapping (address => bool) voted;
}
struct Vote {
bool inSupport;
address voter;
}
// Modifier that allows only shareholders to vote and create new proposals
modifier onlyShareholders {
require(sharesTokenAddress.balanceOf(msg.sender) > 0);
_;
}
/**
* Constructor function
*
* First time setup
*/
function Association(Token sharesAddress, uint minimumSharesToPassAVote, uint minutesForDebate) payable {
changeVotingRules(sharesAddress, minimumSharesToPassAVote, minutesForDebate);
}
/**
* Change voting rules
*
* Make so that proposals need to be discussed for at least `minutesForDebate/60` hours
* and all voters combined must own more than `minimumSharesToPassAVote` shares of token `sharesAddress` to be executed
*
* @param sharesAddress token address
* @param minimumSharesToPassAVote proposal can vote only if the sum of shares held by all voters exceed this number
* @param minutesForDebate the minimum amount of delay between when a proposal is made and when it can be executed
*/
function changeVotingRules(Token sharesAddress, uint minimumSharesToPassAVote, uint minutesForDebate) onlyOwner {
sharesTokenAddress = Token(sharesAddress);
if (minimumSharesToPassAVote == 0 ) minimumSharesToPassAVote = 1;
minimumQuorum = minimumSharesToPassAVote;
debatingPeriodInMinutes = minutesForDebate;
ChangeOfRules(minimumQuorum, debatingPeriodInMinutes, sharesTokenAddress);
}
/**
* Add Proposal
*
* Propose to send `weiAmount / 1e18` ether to `beneficiary` for `jobDescription`. `transactionBytecode ? Contains : Does not contain` code.
*
* @param beneficiary who to send the ether to
* @param weiAmount amount of ether to send, in wei
* @param jobDescription Description of job
* @param transactionBytecode bytecode of transaction
*/
function newProposal(
address beneficiary,
uint weiAmount,
string jobDescription,
bytes transactionBytecode
)
onlyShareholders
returns (uint proposalID)
{
proposalID = proposals.length++;
Proposal storage p = proposals[proposalID];
p.recipient = beneficiary;
p.amount = weiAmount;
p.description = jobDescription;
p.proposalHash = sha3(beneficiary, weiAmount, transactionBytecode);
p.votingDeadline = now + debatingPeriodInMinutes * 1 minutes;
p.executed = false;
p.proposalPassed = false;
p.numberOfVotes = 0;
ProposalAdded(proposalID, beneficiary, weiAmount, jobDescription);
numProposals = proposalID+1;
return proposalID;
}
/**
* Add proposal in Ether
*
* Propose to send `etherAmount` ether to `beneficiary` for `jobDescription`. `transactionBytecode ? Contains : Does not contain` code.
* This is a convenience function to use if the amount to be given is in round number of ether units.
*
* @param beneficiary who to send the ether to
* @param etherAmount amount of ether to send
* @param jobDescription Description of job
* @param transactionBytecode bytecode of transaction
*/
function newProposalInEther(
address beneficiary,
uint etherAmount,
string jobDescription,
bytes transactionBytecode
)
onlyShareholders
returns (uint proposalID)
{
return newProposal(beneficiary, etherAmount * 1 ether, jobDescription, transactionBytecode);
}
/**
* Check if a proposal code matches
*
* @param proposalNumber ID number of the proposal to query
* @param beneficiary who to send the ether to
* @param weiAmount amount of ether to send
* @param transactionBytecode bytecode of transaction
*/
function checkProposalCode(
uint proposalNumber,
address beneficiary,
uint weiAmount,
bytes transactionBytecode
)
constant
returns (bool codeChecksOut)
{
Proposal storage p = proposals[proposalNumber];
return p.proposalHash == sha3(beneficiary, weiAmount, transactionBytecode);
}
/**
* Log a vote for a proposal
*
* Vote `supportsProposal? in support of : against` proposal #`proposalNumber`
*
* @param proposalNumber number of proposal
* @param supportsProposal either in favor or against it
*/
function vote(
uint proposalNumber,
bool supportsProposal
)
onlyShareholders
returns (uint voteID)
{
Proposal storage p = proposals[proposalNumber];
require(p.voted[msg.sender] != true);
voteID = p.votes.length++;
p.votes[voteID] = Vote({inSupport: supportsProposal, voter: msg.sender});
p.voted[msg.sender] = true;
p.numberOfVotes = voteID +1;
Voted(proposalNumber, supportsProposal, msg.sender);
return voteID;
}
/**
* Finish vote
*
* Count the votes proposal #`proposalNumber` and execute it if approved
*
* @param proposalNumber proposal number
* @param transactionBytecode optional: if the transaction contained a bytecode, you need to send it
*/
function executeProposal(uint proposalNumber, bytes transactionBytecode) {
Proposal storage p = proposals[proposalNumber];
require(now > p.votingDeadline // If it is past the voting deadline
&& !p.executed // and it has not already been executed
&& p.proposalHash == sha3(p.recipient, p.amount, transactionBytecode)); // and the supplied code matches the proposal...
// ...then tally the results
uint quorum = 0;
uint yea = 0;
uint nay = 0;
for (uint i = 0; i < p.votes.length; ++i) {
Vote storage v = p.votes[i];
uint voteWeight = sharesTokenAddress.balanceOf(v.voter);
quorum += voteWeight;
if (v.inSupport) {
yea += voteWeight;
} else {
nay += voteWeight;
}
}
require(quorum >= minimumQuorum); // Check if a minimum quorum has been reached
if (yea > nay ) {
// Proposal passed; execute the transaction
p.executed = true;
require(p.recipient.call.value(p.amount)(transactionBytecode));
p.proposalPassed = true;
} else {
// Proposal failed
p.proposalPassed = false;
}
// Fire Events
ProposalTallied(proposalNumber, yea - nay, quorum, p.proposalPassed);
}
}
DEPLOYMENT AND USAGE
The code is deployed exactly like the previous code, but you need to put the shares token address which is the address of the token that will work as a share with voting rights.
Notice these lines of codes: first we describe the token contract to our new contract. Since it only uses the balance of function, we only need to add that single line.
contract Token { mapping (address => uint256) public balanceOf; }
Then we define a variable of the type token, meaning that it will inherit all the functions we described earlier. Finally, we point the token variable to an address on the blockchain, so it can use that and request live information. This is the simplest way to make one contract understand the other in Yocoin.
contract Association {
token public sharesTokenAddress;
// ...
function Association(token sharesAddress, uint minimumSharesForVoting, uint minutesForDebate) {
sharesTokenAddress = token(sharesAddress);
This association presents a challenge that the previous congress didn’t have. The actual score of the proposal can’t be counted when the shareholder votes, otherwise someone would be able to vote multiple times by simply sending his share to different addresses since anyone with tokens can vote and the balances can change very quickly. So, only the vote position is recorded and then the real score is tallied up on the execute proposal phase.
uint quorum = 0;
uint yea = 0;
uint nay = 0;
for (uint i = 0; i < p.votes.length; ++i) {
Vote v = p.votes[i];
uint voteWeight = sharesTokenAddress.balanceOf(v.voter);
quorum += voteWeight;
if (v.inSupport) {
yea += voteWeight;
} else {
nay += voteWeight;
}
}
Another way to count the weighted votes would be to create a single signed integer to keep score of the votes and check if it was positive or negative at the end, but you’d have to convert the unsigned integer voteWeight into a signed integer using int score = int(voteWeight);
Using this DAO is the same: members create new proposals, vote on them, wait until the deadline passes and then anyone can count the votes and execute it.
BUT HOW CAN I LIMIT THE OWNER’S POWER?
On this contract the address set as owner has some special powers: they can add or ban members as they want, change the margin needed for a win, alter the time required for debate and the quorum necessary for the vote to pass. But this can be solved by using yet another power the owner has: to change ownership.
The owner could change the ownership to no one by pointing the new owner as 0x00000…. This would guarantee that the rules will never change, but it’s an irreversible action. The owner can also change the ownership of the contract itself: just click on “copy address” and add it on the “new owner” field. This would make that all the powers of the owner could be executed by creating proposals.
If you want, you can also set one contract as the owner of the other: suppose you wanted a corporate structure where you wanted a President for life that had the power to appoint board members, which could then issue more shares and finally these shares voted on how to spend a budget. You could create an Associationcontract, that used a mintable token owned by a congress finally owned by a single account.
But what if you wanted different rules for voting? Maybe to change voting rules you’d need a 80% consensus or maybe the members are different. In that case, you can create another identical DAO or use some other source code and plug that one as the owner of the first.
Liquid democracy
Voting on all expenses and actions of a contract takes time and requires users to be constantly active, informed and attentive. Another interesting approach is to elect an appointed account that will have control over a contract and then be able to take swift decisions over it.
We are going to implement a version of what’s usually called Liquid Democracy, which is a more flexible delegative democracy. In this kind of democracy, any voter can be a potential delegate: instead of voting the candidate you want, you just say which voter you trust to handle this decision for you. Your voting weight is delegated to them and they can in turn delegate it to another voter they trust and so on. The end result should be that the most voted account is one that has trust connections to the largest number of voters.
pragma solidity ^0.4.16;
contract token {
mapping (address => uint256) public balanceOf;
}
contract LiquidDemocracy {
token public votingToken;
bool underExecution;
address public appointee;
mapping (address => uint) public voterId;
mapping (address => uint256) public voteWeight;
uint public delegatedPercent;
uint public lastWeightCalculation;
uint public numberOfDelegationRounds;
uint public numberOfVotes;
DelegatedVote[] public delegatedVotes;
string public forbiddenFunction;
event NewAppointee(address newAppointee, bool changed);
struct DelegatedVote {
address nominee;
address voter;
}
/**
* Constructor function
*/
function LiquidDemocracy(
address votingWeightToken,
string forbiddenFunctionCall,
uint percentLossInEachRound
) {
votingToken = token(votingWeightToken);
delegatedVotes.length++;
delegatedVotes[0] = DelegatedVote({nominee: 0, voter: 0});
forbiddenFunction = forbiddenFunctionCall;
delegatedPercent = 100 - percentLossInEachRound;
if (delegatedPercent > 100) delegatedPercent = 100;
}
/**
* Vote for an address
*
* Send your vote weight to another address
*
* @param nominatedAddress the destination address receiving the sender's vote
*/
function vote(address nominatedAddress) returns (uint voteIndex) {
if (voterId[msg.sender]== 0) {
voterId[msg.sender] = delegatedVotes.length;
numberOfVotes++;
voteIndex = delegatedVotes.length++;
numberOfVotes = voteIndex;
}
else {
voteIndex = voterId[msg.sender];
}
delegatedVotes[voteIndex] = DelegatedVote({nominee: nominatedAddress, voter: msg.sender});
return voteIndex;
}
/**
* Perform Executive Action
*
* @param target the destination address to interact with
* @param valueInWei the amount of ether to send along with the transaction
* @param bytecode the data bytecode for the transaction
*/
function execute(address target, uint valueInWei, bytes32 bytecode) {
require(msg.sender == appointee // If caller is the current appointee,
&& !underExecution // // if the call is being executed,
&& bytes4(bytecode) != bytes4(sha3(forbiddenFunction)) // and it's not trying to do the forbidden function
&& numberOfDelegationRounds >= 4); // and delegation has been calculated enough
underExecution = true;
assert(target.call.value(valueInWei)(bytecode)); // Then execute the command.
underExecution = false;
}
/**
* Calculate Votes
*
* Go thruogh all the delegated vote logs and tally up each address's total rank
*/
function calculateVotes() returns (address winner) {
address currentWinner = appointee;
uint currentMax = 0;
uint weight = 0;
DelegatedVote storage v = delegatedVotes[0];
if (now > lastWeightCalculation + 90 minutes) {
numberOfDelegationRounds = 0;
lastWeightCalculation = now;
// Distribute the initial weight
for (uint i=1; i< delegatedVotes.length; i++) {
voteWeight[delegatedVotes[i].nominee] = 0;
}
for (i=1; i< delegatedVotes.length; i++) {
voteWeight[delegatedVotes[i].voter] = votingToken.balanceOf(delegatedVotes[i].voter);
}
}
else {
numberOfDelegationRounds++;
uint lossRatio = 100 * delegatedPercent ** numberOfDelegationRounds / 100 ** numberOfDelegationRounds;
if (lossRatio > 0) {
for (i=1; i< delegatedVotes.length; i++){
v = delegatedVotes[i];
if (v.nominee != v.voter && voteWeight[v.voter] > 0) {
weight = voteWeight[v.voter] * lossRatio / 100;
voteWeight[v.voter] -= weight;
voteWeight[v.nominee] += weight;
}
if (numberOfDelegationRounds>3 && voteWeight[v.nominee] > currentMax) {
currentWinner = v.nominee;
currentMax = voteWeight[v.nominee];
}
}
}
}
if (numberOfDelegationRounds > 3) {
NewAppointee(currentWinner, appointee == currentWinner);
appointee = currentWinner;
}
return currentWinner;
}
}
DEPLOYMENT
First, you need a token. If you have followed the Shareholder association tutorial above, you can use the same token as you had previously, otherwise just deploy a new token and distribute it among some accounts. Copy the token address.
Deploy the democracy contract and put the token address on the Voting weight token, put 75 as the Percent loss in each round and transferOwnership(address) (without any spaces or extra characters!) as the forbidden function.
SELECTING A DELEGATE
Now deploy the Liquid democracy and go to its page. First have any of the shareholders vote on who they would trust to make decisions on behalf of this contract. You can vote on yourself if you want to be the final decision maker, or on the zero address, if you’d rather have no one representing you on that role.
After enough people have cast their votes, you can execute the function Calculate Votes so it will calculate everyone’s voting weight. This function needs to be run multiple times, so the first run it will just set everyone’s weight as their balance in the selected token, in the next round that voting weight will go to the person you voted appointed, in the next it will go to the person voted by the person you chose and so on. To prevent infinite loops of vote delegations, each time a vote is forwarded it loses a bit of power, set by at contract launch at percentLossInEachRound. So, if the loss is set at 75%, it means that the person you vote gets 100% of your weight, but if they delegate the vote to someone else only 75% of their weight is forwarded. That person can delegate to someone else, but they’ll get only 56% of your voting weight and so on. If the ratio is anything lower than 100% there will be a finite moment where recalculating voting delegation won’t change the result anymore, but if it’s a 100% it means that voting weights will simply circulate around any potential loops.
If there has been more than one hour and a half since this round of calling Calculate votes has started, all weights will reset and will be recalculated based on the original token balance, so if you have recently received more tokens you should execute this function again.
HOUSE OF REPRESENTATIVES
What is all that vote delegation good for? For one, you can use it instead of the token weight on an Association. Firstly, get the code for a shareholder associationbut replace the first lines where it describes the token:
contract Token {
mapping (address => uint256) public balanceOf;
function transferFrom(address _from, address _to, uint256 _value) returns (bool success);
}
Into this:
contract Token {
mapping (address => uint256) public voteWeight;
uint public numberOfDelegationRounds;
function balanceOf(address member) constant returns (uint256 balance) {
if (numberOfDelegationRounds < 3)
return 0;
else
return this.voteWeight(member);
}
function transferFrom(address _from, address _to, uint256 _value) returns (bool success);
}
When you are writing your contract, you can describe multiple other contracts used by your main contract. Some might be functions and variables that are already defined on the target contract, like voteWeight and numberOfDelegationRounds. But notice that balanceOf is a new function, that doesn’t exist neither on the Liquid Democracy nor the Association contract. We are defining it as a function that will return the voteWeight if at least three rounds of delegations have been calculated.
Use the Liquid democracy as the Token Address instead of the original token and proceed to deploy the shareholder association as usual. Just like before, users can create new proposals on what to do or cast votes on these issues, but now, instead of using the token balance as the voting power we are using a delegative process. So, if you are a token holder, instead of having to keep yourself constantly informed by all the issues, you can just select someone you trust and appoint them, and then they can choose someone they trust: the result is that your representative, instead of being limited to a given arbitrary geographical proximity, will be someone in your social proximity.
Also, it means that you can switch your vote at any moment: if your representative has voted against your interests in some issue you can, before the proposal votes are tallied up, switch your appointee, or just choose to represent yourself on the issue and cast the vote yourself.
THE EXECUTIVE BRANCH
Delegative democracies are a great way to choose representatives, but voting on individual proposals might be too slow for some important or simpler decisions: that’s why most democratic governments have an executive branch, where an appointed person has the right to represent the state.
After four rounds of delegations, the address with more weight will be set as the Appointee. If there are many delegated votes, then a few more rounds of Calculate Votes might be necessary to settle in the final appointed address.
The Appointee is the only address that can call the Execute function, which will be able to execute (almost) any function representing the democracy as a whole. If there is any YOC or token stored in the Liquid democracy contract, the Appointee will be allowed to move it anywhere.
If you have followed our example and created a Shareholder association using this liquid democracy as a token, then you should be able to use the executive branch in an interesting manner: go to the main Association address and execute a Transfer Ownership function to the liquid democracy.
Once that transfer is complete, switch the function to Change Voting Rules. This allows you to change some essential voting rules, like the minimum quorum needed for a vote to pass or the time a new proposal needs to stay on the floor. Try changing these settings and click execute: when the confirmation window pops up it will tell you that the transaction Can’t be executed. This happens, of course, because only the address set as Owner can change these settings and the contract will reject this transaction attempt. So instead of typing your password copy the code on the data field and save it to a text file. Click cancel, scroll to the top and click copy address and save that to a text file.
Now go to the Liquid democracy page and choose execute. On target put the address of the association contract, leave YOC amount at 0 and paste the code you copied previously into the bytecode data field. Make sure you are executing it from the account set as the appointee and click execute.
Once the transaction has been picked up, the Liquid democracy will pass the order to the association and the new voting rules might apply. The appointee has the absolute power to do anything that the Liquid democracy contract can execute. You can use the same technique to create a Mintable Token owned by the delegative democracy, and then allow the appointee to mint tokens or freeze accounts.
To prevent abuses of powers, you can set one Forbidden function that the Appointee cannot ever do. If you followed our example the forbidden function is the transferOwnership(address), to prevent the appointee from transferring the ownership of the association to themselves (in politics, when a president uses his executive power to transfer to themselves something that used to belongs to the presidency, it’s a coup or embezzling).
Time-Locked Multisig
Sometimes time can also be used as a great security mechanism. The following code is based on the congress DAO but with a different twist. Instead of every action requiring the approval of an X number of members, instead any transactions can be initiated by a single member, but they all will require a minimum amount of delay before they can be executed, which varies according to the support that transaction has. The more approvals a proposal has, the sooner it can be executed. A member can vote against a transaction, which will mean that it will cancel one of the other approved signatures.
This means that if you don’t have urgency, one or two signatures might be all you need to execute any transaction. But if a single key is compromised, other keys can delay that transaction for months or year or even stop it from being executed.
HOW IT WORKS
A transaction that has been approved by all keys can be executed after ten minutes (this amount is configurable), and the amount of time it requires doubles every time for every 5% of members who don’t vote (and quadruples if they actively vote against). If it’s a simple YOC transaction, the transaction is executed as soon as a vote of support puts it under the required time, but a more complex transaction will require it to be manually executed with the correct bytecode. These are the default values, but this can be set differently when creating the contract:
Number of members approving transaction: Approximate time delay
- 100% approval: 10 minutes (minimum default)
- 90% approval: 40 minutes
- 80%: 2hr 40min
- 50%: about a week
- 40%: 1 month
- 30%: 4 months
- 20%: Over a year
- 10% or less: 5 years or never
Once the minimum amount of time has passed, anyone can execute the transaction (See “Congress” for a more complete walktrough). This is intentional, as it allows someone to schedule a transaction or hire someone else to execute it.
pragma solidity ^0.4.16;
contract owned {
address public owner;
function owned() {
owner = msg.sender;
}
modifier onlyOwner {
require(msg.sender == owner);
_;
}
function transferOwnership(address newOwner) onlyOwner {
owner = newOwner;
}
}
contract tokenRecipient {
event receivedEther(address sender, uint amount);
event receivedTokens(address _from, uint256 _value, address _token, bytes _extraData);
function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData){
Token t = Token(_token);
require(t.transferFrom(_from, this, _value));
receivedTokens(_from, _value, _token, _extraData);
}
function () payable {
receivedEther(msg.sender, msg.value);
}
}
interface Token {
function transferFrom(address _from, address _to, uint256 _value) returns (bool success);
}
contract TimeLockMultisig is owned, tokenRecipient {
Proposal[] public proposals;
uint public numProposals;
mapping (address => uint) public memberId;
Member[] public members;
uint minimumTime = 10;
event ProposalAdded(uint proposalID, address recipient, uint amount, string description);
event Voted(uint proposalID, bool position, address voter, string justification);
event ProposalExecuted(uint proposalID, int result, uint deadline);
event MembershipChanged(address member, bool isMember);
struct Proposal {
address recipient;
uint amount;
string description;
bool executed;
int currentResult;
bytes32 proposalHash;
uint creationDate;
Vote[] votes;
mapping (address => bool) voted;
}
struct Member {
address member;
string name;
uint memberSince;
}
struct Vote {
bool inSupport;
address voter;
string justification;
}
// Modifier that allows only shareholders to vote and create new proposals
modifier onlyMembers {
require(memberId[msg.sender] != 0);
_;
}
/**
* Constructor function
*
* First time setup
*/
function TimeLockMultisig(address founder, address[] initialMembers, uint minimumAmountOfMinutes) payable {
if (founder != 0) owner = founder;
if (minimumAmountOfMinutes !=0) minimumTime = minimumAmountOfMinutes;
// It’s necessary to add an empty first member
addMember(0, '');
// and let's add the founder, to save a step later
addMember(owner, 'founder');
changeMembers(initialMembers, true);
}
/**
* Add member
*
* @param targetMember address to add as a member
* @param memberName label to give this member address
*/
function addMember(address targetMember, string memberName) onlyOwner {
uint id;
if (memberId[targetMember] == 0) {
memberId[targetMember] = members.length;
id = members.length++;
} else {
id = memberId[targetMember];
}
members[id] = Member({member: targetMember, memberSince: now, name: memberName});
MembershipChanged(targetMember, true);
}
/**
* Remove member
*
* @param targetMember the member to remove
*/
function removeMember(address targetMember) onlyOwner {
require(memberId[targetMember] != 0);
for (uint i = memberId[targetMember]; i<members.length-1; i++){
members[i] = members[i+1];
}
delete members[members.length-1];
members.length--;
}
/**
* Edit existing members
*
* @param newMembers array of addresses to update
* @param canVote new voting value that all the values should be set to
*/
function changeMembers(address[] newMembers, bool canVote) {
for (uint i = 0; i < newMembers.length; i++) {
if (canVote)
addMember(newMembers[i], '');
else
removeMember(newMembers[i]);
}
}
/**
* Add Proposal
*
* Propose to send `weiAmount / 1e18` ether to `beneficiary` for `jobDescription`. `transactionBytecode ? Contains : Does not contain` code.
*
* @param beneficiary who to send the ether to
* @param weiAmount amount of ether to send, in wei
* @param jobDescription Description of job
* @param transactionBytecode bytecode of transaction
*/
function newProposal(
address beneficiary,
uint weiAmount,
string jobDescription,
bytes transactionBytecode
)
onlyMembers
returns (uint proposalID)
{
proposalID = proposals.length++;
Proposal storage p = proposals[proposalID];
p.recipient = beneficiary;
p.amount = weiAmount;
p.description = jobDescription;
p.proposalHash = sha3(beneficiary, weiAmount, transactionBytecode);
p.executed = false;
p.creationDate = now;
ProposalAdded(proposalID, beneficiary, weiAmount, jobDescription);
numProposals = proposalID+1;
vote(proposalID, true, '');
return proposalID;
}
/**
* Add proposal in Ether
*
* Propose to send `etherAmount` ether to `beneficiary` for `jobDescription`. `transactionBytecode ? Contains : Does not contain` code.
* This is a convenience function to use if the amount to be given is in round number of ether units.
*
* @param beneficiary who to send the ether to
* @param etherAmount amount of ether to send
* @param jobDescription Description of job
* @param transactionBytecode bytecode of transaction
*/
function newProposalInEther(
address beneficiary,
uint etherAmount,
string jobDescription,
bytes transactionBytecode
)
onlyMembers
returns (uint proposalID)
{
return newProposal(beneficiary, etherAmount * 1 ether, jobDescription, transactionBytecode);
}
/**
* Check if a proposal code matches
*
* @param proposalNumber ID number of the proposal to query
* @param beneficiary who to send the ether to
* @param weiAmount amount of ether to send
* @param transactionBytecode bytecode of transaction
*/
function checkProposalCode(
uint proposalNumber,
address beneficiary,
uint weiAmount,
bytes transactionBytecode
)
constant
returns (bool codeChecksOut)
{
Proposal storage p = proposals[proposalNumber];
return p.proposalHash == sha3(beneficiary, weiAmount, transactionBytecode);
}
/**
* Log a vote for a proposal
*
* Vote `supportsProposal? in support of : against` proposal #`proposalNumber`
*
* @param proposalNumber number of proposal
* @param supportsProposal either in favor or against it
* @param justificationText optional justification text
*/
function vote(
uint proposalNumber,
bool supportsProposal,
string justificationText
)
onlyMembers
{
Proposal storage p = proposals[proposalNumber]; // Get the proposal
require(p.voted[msg.sender] != true); // If has already voted, cancel
p.voted[msg.sender] = true; // Set this voter as having voted
if (supportsProposal) { // If they support the proposal
p.currentResult++; // Increase score
} else { // If they don't
p.currentResult--; // Decrease the score
}
// Create a log of this event
Voted(proposalNumber, supportsProposal, msg.sender, justificationText);
// If you can execute it now, do it
if ( now > proposalDeadline(proposalNumber)
&& p.currentResult > 0
&& p.proposalHash == sha3(p.recipient, p.amount, '')
&& supportsProposal) {
executeProposal(proposalNumber, '');
}
}
function proposalDeadline(uint proposalNumber) constant returns(uint deadline) {
Proposal storage p = proposals[proposalNumber];
uint factor = calculateFactor(uint(p.currentResult), (members.length - 1));
return p.creationDate + uint(factor * minimumTime * 1 minutes);
}
function calculateFactor(uint a, uint b) constant returns (uint factor) {
return 2**(20 - (20 * a)/b);
}
/**
* Finish vote
*
* Count the votes proposal #`proposalNumber` and execute it if approved
*
* @param proposalNumber proposal number
* @param transactionBytecode optional: if the transaction contained a bytecode, you need to send it
*/
function executeProposal(uint proposalNumber, bytes transactionBytecode) {
Proposal storage p = proposals[proposalNumber];
require(now >= proposalDeadline(proposalNumber) // If it is past the voting deadline
&& p.currentResult > 0 // and a minimum quorum has been reached
&& !p.executed // and it is not currently being executed
&& checkProposalCode(proposalNumber, p.recipient, p.amount, transactionBytecode)); // and the supplied code matches the proposal...
p.executed = true;
assert(p.recipient.call.value(p.amount)(transactionBytecode));
// Fire Events
ProposalExecuted(proposalNumber, p.currentResult, proposalDeadline(proposalNumber));
}
}
DEPLOYMENT AND USAGE
Deploy that code as you have done before on these tutorials. On the deployment parameters, leaving the minimum time blank will default to 30 minutes, if you want faster lock times, then put 1 minute. After uploading, execute the functions “Add Members” to add new members of your group, they can be either other people you know or accounts on different computers or stored offline.
The account set as “owner” is very powerful as it can add or remove members at will. Therefore, after you added the main members, we recommend that you set the “owner” to another account, by executing the function Transfer Membership. Set that to the multisig itself if you want to have all additions or removals of members to be voted, just like any other transaction. Another alternative is to set that to another trusted multisig wallet, or maybe to 0x000 if you want the number of members to be fixed forever. Remember, the funds on this contract are only as safe as the the “owner” account.
As with any of the above DAO’s, this contract can hold YOC, any YOCoin based tokens and execute any contract. To do that, check how to execute complex proposals on the congress DAO.
CAVEATS AND IMPROVEMENTS
For simplicity’s sake, a vote against a proposal simply counts as one less vote of support. If you want, you can play around with the idea that negative votes have more weight, but this means that a minority of members could have an effective veto power on any proposed transaction!
How else could you improve this contract?
Let’s go exploring!
You have reached the end of this tutorial, but it’s just the beginning of a great adventure. Look back and see how much you accomplished: you created a living, talking robot, your own cryptocurrency, raised funds through a trustless crowdfunding and used it to kickstart your own personal democratic organization.
WHAT COULD HAPPEN NEXT?
- The tokens you still control could be sold on a decentralized exchange or traded for goods and services to fund further development of the first contract and grow the organization.
- Your DAO could own its own name on the name registrar, and then change where it’s redirecting in order to update itself if the token holders approved.
- The organization could hold not only YOCs, but any other kind of coin created on YOCoin, including assets whose values are tied to the bitcoin or dollar.
- The DAO could be programmed to allow a proposal with multiple transactions, some scheduled to the future. It could also own shares of other DAOs, meaning it could vote on larger organization or be a part of a federation of DAOs.
- The Token Contract could be reprogrammed to hold YOC or to hold other tokens and distribute it to the token holders. This would link the value of the token to the value of other assets, so paying dividends could be accomplished by simply moving funds to the token address.
This all means that this tiny society you created could grow, get funding from third parties, pay recurrent salaries, own any kind of crypto-assets and even use crowdsales to fund its activities. All with full transparency, complete accountability and complete immunity from any human interference. While the network lives the contracts will execute exactly the code they were created to execute, without any exception, forever.
So, what will your contract be? Will it be a country, a company, a non-profit group? What will your code do?
That’s up to you.
yocoin 