We will create a basic swap smart contract that will allow two users, Alice and Bob, to exchange two minimal tokens safely. The contracts will be specific to the two users and unidirectional.
A core functionality of your smart contract is the ability to sell tickets. You will sell them for 0.1 Ethers. An Ethereum address could own several tickets.
@ -20,7 +20,7 @@ First, we will create a simple stablecoin, following the ERC20 standard and an o
---
# Exercise 1: Stablecoin
## Exercise 1: Stablecoin
The purpose of this exercise is to create a fully collateralized stablecoin. We will use an oracle smart contract to get the current value of any volatile token.
@ -54,7 +54,7 @@ And, the keystone, we allow any user to punish users that issued more tokens tha
---
# Exercise 2: Lending Platform
## Exercise 2: Lending Platform
We will create a platforms that allow borrowers tokens from lenders in a decentralized manner around a volatile and a stable token. Lenders will earn a fixed yield of 5% per year.
@ -92,7 +92,7 @@ _Optional provide a web interface for the lending platform_
---
# Exercise 3: Tests and Coverage
## Exercise 3: Tests and Coverage
To produce adequate tests is the first obvious step to start applying good security measures. We will create the tests for the stablecoin smart contract.
_If you don't believe it or don't get it, I don't have the time to try to convince you, sorry. — Satoshi Nakamoto_
@ -19,7 +19,7 @@ In this course, we will focus on two solutions provided by the Hyperledger proje
---
# Exercise 1: Private Network
## Exercise 1: Private Network
Besu in an alternative Ethereum client that is compatible with Ethereum mainnet. It facilitates the deployment of private networks. Will we use the QBFT consensus algorithm, a Proof of Authority Byzantine Fault Tolerant algorithm
@ -64,7 +64,7 @@ Network/
---
# Exercise 2: Clillet
## Exercise 2: Clillet
The goal of this raid is to create a fully functional command line wallet for a blockchain of your choice. You can choose any of the major alternative blockchains: Solana, Tezos, Poladot, Cosmos... The executable `clillet` must follow and implement the help description below. Our wallet consists of the following subcommands
_"Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter." - Eric S. Raymond_
@ -6,7 +6,7 @@ One of the key elements of blockchains' value proposition is providing the techn
In that context, we will build a financial instruments platform. First, we will represent a stablecoin, shares and bonds on a private blockchain network. Then a marketplace website will allow users to list, buy and sell assets.
In this project, you are free to use the blockchain, technologies, and tools that you want. However, the project must offer complete documentation.
In this project, you are free to use the blockchain, technologies, and tools that you want. However, the project must offer complete documentation.
## Private network
@ -16,56 +16,56 @@ The network must have a minimum of 3 validating nodes. A script must facilitate
Three categories of financial instruments can be exchanged on the platform. Functionally, each asset is a type of smart contract
***Stablecoins**: It must be a standard fungible token (ERC20 or equivalent). It initially has 1000 units. The creator of the stablecoin can issue or remove units.
***Shares**: Shares are a fungible token for each company. Occasionally, its issuer can do a dividend payout. In that case, the issuer sends the stablecoin to the share contract, and each owner can retrieve proportionally to its possessions.
* **Bonds: **A smart contract represents all the outstanding bonds from an issuer. Each bond has a unique serial number, a current principal, an interest rate, an issuance date, a maturity date, a current owner, and if it has been repaid. For simplicity, we assume each bond to be issued for one year, requiring only one payment.
-**Stablecoins**: It must be a standard fungible token (ERC20 or equivalent). It initially has 1000 units. The creator of the stablecoin can issue or remove units.
-**Shares**: Shares are a fungible token for each company. Occasionally, its issuer can do a dividend payout. In that case, the issuer sends the stablecoin to the share contract, and each owner can retrieve proportionally to its possessions.
- **Bonds: **A smart contract represents all the outstanding bonds from an issuer. Each bond has a unique serial number, a current principal, an interest rate, an issuance date, a maturity date, a current owner, and if it has been repaid. For simplicity, we assume each bond to be issued for one year, requiring only one payment.
## Populating
In order to facilitate tests and audits, we will populate those financial instruments. An interactive script is available to create several addresses and deploy smart contracts.
In order to facilitate tests and audits, we will populate those financial instruments. An interactive script is available to create several addresses and deploy smart contracts.
* A stablecoin called “triangle” with the ticker “TRG” and 4000 units available.
* Shares from “Clove Company” represented as “CLV” and “Rooibos Limited” “ROO”, with 100 shares each.
* Government bonds, “GOV”, for a principal of 200 each and an interest rate of 10%, 20 units.
- A stablecoin called “triangle” with the ticker “TRG” and 4000 units available.
- Shares from “Clove Company” represented as “CLV” and “Rooibos Limited” “ROO”, with 100 shares each.
- Government bonds, “GOV”, for a principal of 200 each and an interest rate of 10%, 20 units.
Each instrument is issued by a distinct address that owns all units initially.
Additionally, the script asks for two Ethereum addresses, Aya and Beatriz.
- Aya should receive 200 TRG, 10 CLV and 2 GOV.
- Beatriz should receive 150 TRV, 20 ROO and 5 GOV.
- Aya should receive 200 TRG, 10 CLV and 2 GOV.
- Beatriz should receive 150 TRV, 20 ROO and 5 GOV.
## Marketplace
The marketplace consists of
The marketplace consists of
- A web interface that allows users to visualise information and give orders.
- A server with an API and a database that stores listed assets and orders.
- A multi-signature vault smart contract that contains customer assets.
* A web interface that allows users to visualise information and give orders.
* A server with an API and a database that stores listed assets and orders.
* A multi-signature vault smart contract that contains customer assets.
Our model is hybrid, as order execution is centralised, but assets are not in full custody of the platform.
Our model is hybrid, as order execution is centralised, but assets are not in full custody of the platform.
## Web interface
The interface must consist of a homepage, an asset page, a portfolio page, and an FAQ page.
### Homepage
An introduction page to the platform that allows the user to connect a wallet
### Asset pages
A page per asset (only share and bonds) that provides on the left a curve with the price of prior trades and on the right control buttons
* The price by default is 10 TRG for a CLV and a ROO share and 200 TRG for GOV bonds. The curve is a straight line until trades are made.
* Command buttons allow users to
* Create a sell order for this asset or a buy order for this asset with an input field allowing them to select the number of units and establish a price.
* To buy or sell a certain asset at the current market price.
_ The price by default is 10 TRG for a CLV and a ROO share and 200 TRG for GOV bonds. The curve is a straight line until trades are made.
_ Command buttons allow users to
_ Create a sell order for this asset or a buy order for this asset with an input field allowing them to select the number of units and establish a price.
_ To buy or sell a certain asset at the current market price.
### Portfolio page
A portfolio page that shows to the user his possessions.
A table shows in one column the number of units available in total for each asset and another column with the amount currently stored on the platform with a button to withdraw it. Each asset name should redirect to the dedicated page.
A table shows in one column the number of units available in total for each asset and another column with the amount currently stored on the platform with a button to withdraw it. Each asset name should redirect to the dedicated page.
<table>
<tr>
@ -131,52 +131,48 @@ Total available</p>
</tr>
</table>
A visualization part allows the user to have a sense of his possession in TRG. For instance, a pie chart proportional to the current price of each asset can be displayed. For instance, assuming the default prices, the table above should render this way.
A visualization part allows the user to have a sense of his possession in TRG. For instance, a pie chart proportional to the current price of each asset can be displayed. For instance, assuming the default prices, the table above should render this way.
### FAQ page
An FAQ page that explains how to use the platform
An FAQ page that explains how to use the platform
## The server
The server serves the fronted using the database information, exposes an API for the frontend and interacts with the blockchain. Its API must offer a function to monitor deposits, triggered from the user interface, that verifies on the blockchain the transaction that sent the funds and another one to authorise withdrawals.
The database contains
* A table with the assets usable on the platform, their type, the address of their smart contract, and their price history.
* A table of the users of the platform registered after the first connection. They must provide their legal name and upload a “passport” picture. No check is made when login in, but the picture is stored for future reference
* A table of all ongoing sell and buy offers on the platform
- A table with the assets usable on the platform, their type, the address of their smart contract, and their price history.
- A table of the users of the platform registered after the first connection. They must provide their legal name and upload a “passport” picture. No check is made when login in, but the picture is stored for future reference
- A table of all ongoing sell and buy offers on the platform
## The vault smart contract
The vault smart contract will receive the various financial assets. In a simple form, it includes an `operateWithdrawal(user, asset, amount)` reserved to the platform issuer allows the platform to send assets to the user, after verifying that the funds were theirs and that there are no pending orders.
The vault smart contract will receive the various financial assets. In a simple form, it includes an `operateWithdrawal(user, asset, amount)` reserved to the platform issuer allows the platform to send assets to the user, after verifying that the funds were theirs and that there are no pending orders.
_Optionally, a more sophisticated security model can be proposed._
## Trade execution
If a user, Aya, wants to sell CLV shares, she will go to the dedicated CLV page. On the panel on the right, she will select a number of shares, for instance 5, among her total number of shares, and a price, for instance, 9. The shares will then be transferred to the smart contract of the platform. Her address however will be approved to retrieve. When a user, Beatriz, wants to buy 3 CLV shares at the current market price, he selects this option on the panel. The platform will select the best offers. In this example, it will retain the 3 shares of Aya as available. Then, the platform will update the balance of both users in its database.
The platform must handle all the cases where various offers must be used to fulfil a demand.
If a user, Aya, wants to sell CLV shares, she will go to the dedicated CLV page. On the panel on the right, she will select a number of shares, for instance 5, among her total number of shares, and a price, for instance, 9. The shares will then be transferred to the smart contract of the platform. Her address however will be approved to retrieve. When a user, Beatriz, wants to buy 3 CLV shares at the current market price, he selects this option on the panel. The platform will select the best offers. In this example, it will retain the 3 shares of Aya as available. Then, the platform will update the balance of both users in its database.
The platform must handle all the cases where various offers must be used to fulfil a demand.
## Withdrawal
At any point, the users can ask to withdraw their funds. On their portfolio page, users can click on assets that are on the platform. The platform server verifies that the assets are not part of any pending offer and send an `operateWithdrawal()` to the vault smart contract. Once validated, the frontend updates the user information.
At any point, the users can ask to withdraw their funds. On their portfolio page, users can click on assets that are on the platform. The platform server verifies that the assets are not part of any pending offer and send an `operateWithdrawal()` to the vault smart contract. Once validated, the frontend updates the user information.
## Documentation
In addition to the FAQ on the website explaining functionality as mentioned in the interface section, we need a full developer documentation. It must explain
* How to launch and deploy the platform. It must contain a step-by-step guide to install dependencies and launch the project.
* Describe how to launch the populating script (see section populating)
* Describe the architecture of the project
* Specify each API function exposed from the server
* Describe in detail each smart contact function of the smart contract vault.
In addition to the FAQ on the website explaining functionality as mentioned in the interface section, we need a full developer documentation. It must explain
The README file at the root of the project must specify where to find this documentation.
- How to launch and deploy the platform. It must contain a step-by-step guide to install dependencies and launch the project.
- Describe how to launch the populating script (see section populating)
- Describe the architecture of the project
- Specify each API function exposed from the server
- Describe in detail each smart contact function of the smart contract vault.
The README file at the root of the project must specify where to find this documentation.
Cryptographic algorithms use a `binary` representation of variables internally (`Buffer` in nodejs). `Hexadecimal` representation is used to facilitate human reading. To get more familiar with the hexadecimal form, we will do a simple operation.
@ -9,10 +9,10 @@ Create a function `increment` that takes as argument a number written in hexadec
In this exercise you will create your first smart contract! For a beginner friendly environment, I recommend [remix](https://remix.ethereum.org). It is an online IDE that provides many useful functionalities.
In this project, we will create a thematic NFT platform that references a genre of NFTs, displays them and allows NFTs trades. By genre of NFT, it can be a visual or thematic category, for instance all NFTs about mediaeval characters, a subcategory of NFTs, for example Profile Pictures (PFP), or more interestingly NFTs used for a particular usage, for instance software licences.
Blockchain nodes participate in a common peer-to-peer network retrieving information, executing and validating transactions and blocks. However, software clients differ in their functionalities and resource consumption. The purpose of this project is to create a tool, `benchy` that can launch, monitor and benchmark Ethereum networks.
Blockchain nodes participate in a common peer-to-peer network retrieving information, executing and validating transactions and blocks. However, software clients differ in their functionalities and resource consumption. The purpose of this project is to create a tool, `benchy` that can launch, monitor and benchmark Ethereum networks.
## launch-network
At first, we will focus on deploying a private Ethereum network while monitoring the nodes. The nodes can be launched directly or within containers.
* The network should consist of five nodes named Alice, Bob, Cassandra, Driss, and Elena. The first three are validating nodes. Each node has a corresponding Ethereum address.
* Two different clients must be used, for instance, Geth and Nethermind
* The consensus mechanism must be clique.
- The network should consist of five nodes named Alice, Bob, Cassandra, Driss, and Elena. The first three are validating nodes. Each node has a corresponding Ethereum address.
- Two different clients must be used, for instance, Geth and Nethermind
- The consensus mechanism must be clique.
The network should be launched with the command `benchy launch-network`. The nodes should be launched in the background and the command should return immediately.
@ -16,28 +16,27 @@ The network should be launched with the command `benchy launch-network`. The nod
Using the `infos` command, Benchy should display information on each node, in the terminal or in a webpage. The information must include:
* Their latest block
* Their list of connected peers
* The number of transactions in their mempool
* Their current CPU and memory consumption (Hint: the outputs of commands such as `docker stats` or `ps` can be used)
* Their corresponding Ethereum address and its balance.
- Their latest block
- Their list of connected peers
- The number of transactions in their mempool
- Their current CPU and memory consumption (Hint: the outputs of commands such as `docker stats` or `ps` can be used)
- Their corresponding Ethereum address and its balance.
## Scenario
To analyze our network, we need to simulate some transactions. Benchy should propose the following scenarios available with the command `benchy scenario X`. Each scenario must provide feedback on its execution, including updated balances after transfers.
0. Initialise the network by letting it run for a few minutes. Validating nodes must have Eth available as reward or part of the initial configuration.
To analyze our network, we need to simulate some transactions. Benchy should propose the following scenarios available with the command `benchy scenario X`. Each scenario must provide feedback on its execution, including updated balances after transfers. 0. Initialise the network by letting it run for a few minutes. Validating nodes must have Eth available as reward or part of the initial configuration.
1. Alice sends every 10 seconds 0.1 ETH to Bob
2. Cassandra deploys an ERC20 smart contract with 3000 tokens BY, and gives 1000 to Driss and 1000 to Elena.
3. Cassandra tries to send 1 ETH to Driss and immediately tries to cancel it by sending a transaction with a higher fee to send it to Elena.
## temporary-failure
To study our network further, benchy can disrupt the current network by randomly stopping one node of the network. The command “temporary-failure X” stops the node X for 40 seconds and puts it back online.
To study our network further, benchy can disrupt the current network by randomly stopping one node of the network. The command “temporary-failure X” stops the node X for 40 seconds and puts it back online.
## Optional
* _an option `-u [time] runs any command continuously each ‘time’ in seconds, 60 by default._
* _Add the possibility to connect one node to a testnet network _
* _Infos displays information only about this node_
* _`Scenario` runs the same scenarios on different addresses_
- _an option `-u [time] runs any command continuously each ‘time’ in seconds, 60 by default._
- _Add the possibility to connect one node to a testnet network _
- _Infos displays information only about this node_
- _`Scenario` runs the same scenarios on different addresses_
In order for your festival to be properly managed, you need to define an organizer. The organizer will be the only user to have the right to modify certain properties. By default, you will define the organizer as the contract's deployer.
To overcome the scalability problem, two types of solutions have been devised. On the one hand the state and payment channels (_payment channels _and state channels_) and on the other hand the secondary chains (_sidechains)_ whose units of value are guaranteed by the main network.
To overcome the scalability problem, two types of solutions have been devised. On the one hand the state and payment channels (_payment channels \_and state channels_) and on the other hand the secondary chains (_sidechains)_ whose units of value are guaranteed by the main network.
Bitcoin offers a network of payment channels, the _lightning network_. On Ethereum there is Raiden, a network of payment channels, µRaiden a micropayments solution, and Counterfactual, a network of state channels. A state channel allows any state to be exchanged, while a payment channel allows only tokens to be exchanged.
@ -33,7 +33,6 @@ As a first stage, we expect the project to work only for one channel between two
| Thunderd A |--connect--| Thunderd B |
+------------+ +------------+
### Smart contract
The **PaymentChannel** contract for a channel between two parts A and B contains:
A Bitcoin transaction consists of one or several inputs and one or several outputs. The sum of the inputs is slightly superior to the sum of the output to take into account the fee. One transaction per block, called "coinbase", pays miners and does not have a valid input. For some transactions, outputs might be null too.
Hash functions are used to secure information. A piece of data, for instance a password, is hashed and only its hash is stored. While there is no way to compute on the original information, one can try every possible value. This is called a brute force attack.
@ -13,8 +13,8 @@ Create a function `semiBrute()` that takes as argument a target, which is a two
### Usage
```js
solution = semiBrute("e2");
console.log(solution);
solution = semiBrute('e2')
console.log(solution)
// One valid result : 'abcdefghijklmnopqrs'
// You might find other valid solutions as we only check the first two characters
You will create your first transaction on Ethereum using one of its testnets. We recommend Goerli as it is the most commonly used testnet, but you can use any other testnet.
@ -16,7 +16,7 @@ You will create your first transaction on Ethereum using one of its testnets. We
One way to distribute our token is to sell it. We will set a fixed price for each token. The tokens will have to be send to the Smart Contract by their owner initally.
We will create a network to track postal parcels using Hyperledger Fabric. Hyperledger Fabric is a modular blockchain framework. It revolves around a few key concepts. First, the notion of channel, which represents a network with a set of transactions and participants dedicated to the same business objective. Within a channel a transaction is validated by a set of designated peers. On this channel, Smart Contracts can be deployed as "chaincode" to define business logic that will control validation within this network.
nprimo
1 year ago
committed by