Proof Of Attendance project combines a browser-based front-end and the L2 chain solution (SKALE) to allow transparent and scalable different organization management and transactional tasks. From signing attendance events to paying recurring salaries, POA project aims to cover them all aspects gradually.

Scaling Ethereum

Proof of Attendance

✋ Propose
🗳️ Vote
🥇 Get $TARO

VoTaro is an Ethereum application that uses a reward system to encourage residents of Queretaro City to propose and participate in activities that will improve their community.

🧰 What do I need to get $ TARO?

You need to do 5 activities to get TARO.

🦊 Download Metamask
🧅 Switch to Skale Network
✔️ Get Validated
🗳️ Delegate TARO
🦸🦸‍♂️ Create and Vote on proposals

Benefits for the city
⛓️ Urban governance on blockchain.
🏙️ Urban processes tracked in Smart Contracts.
🤖 Automation and Decentralization of services.
🧙‍♂️ Citizens develop digital skills.
🤝 Transparent and decentralized urban consensus.
🧬 Predictive Economy and Urban Development.

Cities Protocol

Kangaroo Discord Bot 🦘
Bringing the next generation of crypto to the masses.

What is it? 🤔
Kangaroo is a crypto tipping bot built with Layer 2 onboarding in mind. It
supports Ethereum and a range of ERC-20 tokens.

Frictionless withdrawals 💸
Typical Ethereum token transactions can have fees upwards of $20. Harness the
power of Layer 2 and withdraw your funds for nearly 100 times less.

Grow your community 👥
Engage your discord server with a plethora community oriented features. Better
yet, give crypto funds that your community members can actually use.

Features 🤩

The Basics ✅
Tip other users, deposit and withdraw ETH and ERC-20 tokens to your Layer 2
wallet.

Layer 2 Native 2️⃣
Kangaroo lives on Layer 2 Ethereum. No slow or expensive user experience.

Roadmap 🛣️
Coming soon to a Kangaroo near you.

Airdrops 🪂
Reward members of your community and boost engagement.

Smart Contracts 📝
Interact with your favorite Dapps from the safety of your own server.

Kangaroo

Elmo just wants to give and get money from all his friends without paying so much money for gas. This project uses Optimism's layer 2 architecture to enable fast, (near) gasless transactions on Ethereum. We wrote the deployment scripts in Python which didn't natively support working with the OVM. I was impressed with the team's ability to understand how Optimism's layer 2 rollup schema worked.

ELMO

This project combines real-world gamification, lending pools, governance, and royalty streaming to make up the core functionality of the Creative Platform.

The Creative Platform is a platform for creatives of all types to collaborate, initialize crowdfunding, and submit content directly to brands of all industries while also boosting fan engagements.

Brands:
* Create a new campaign to add liquidity to a pool that creatives can submit content to by depositing Creative tokens (CRTV).

* After the submission deadline, a governance vote is put in place for choosing the winner.

    - Fans can vote for winners based on staking mechanisms (PoolTogether protocol).

* Earned interest and final NFT from the campaign pool goes to the winners and participants of the brand's campaign. 


Creatives:

* Can submit to brand campaigns via uploaded content.

* Mint royalty NFTs

* Collaborate with other creatives.

* Open individual liquidity pools (after unlocking the perk based on your "Star Power" metrics).
    - These liquidity pools can be used for touring, album budgets, music videos, etc.

Fans:
* Can stake into a creative's liquidity pool. 
* Can vote on creative decisions throughout the artists career.
* Can vote on brand submissions.
* Win exclusive and rare (creative x brand) collaboration NFT assets that earn royalties.

Creative

Popcorn removes all barriers to contributing to social good by offering yield optimizer contracts where the fees fund educational, environmental and open source initiatives.

In this project we make it simple to grow your crypto assets on Optimism, while harnessing the security and battle-tested Ethereum Layer 1 yield farming strategies. You can have the best of both worlds! This project demonstrates how to leverage the low gas fees of Optimism to enter into and withdraw from layer 1 yield farming strategies.

Popcorn

XLN is an implementation of Extended Lightning Network on top of Ethereum. 

Send, trade, borrow and lend any ERC20 token instantly paying no gas-fees.

Channels, being the oldest and simplest to implement layer2 technology, are some of the least used ones. Lightning Network has less TVL lower than a medium sized DeFi project on ETH. Raiden (essentially Lightning Network on ETH) has $420 TVL on mainnet after more than 2 years on mainnet.

# Why is that? Do we even correctly understand channels?

I don't think the failure should be attributed to the developing teams or their marketing efforts, instead I claim the one and only reason failure of channel networks failure  is its strict collateral lockup requirements, also known as "inbound capacity problem". 

Under original no-tradeoff LN architecture a new user cannot onboard without making a hub to commit some collateral to their relationship. The incentives are just not there for this to happen.

# Solution: credit lines

I propose to solve it using a similar approach rollups currently use for instant confirmation: a fractional reserve-based promise aka credit line given by the hub/operator to the end user, that the assets will be collateralized in the future (in case of XLN) or the tx will be included  in the batch (in case of rollups).

Instead of being collateral-only XLN channels allow any user to open a credit line to other user up to specific credit limit. This alleviates the "no route/capacity" problem of original LN/Raiden.


# Why would we still benefit from channel networks when we have rollups being ready?

1. scalability of XLN is unbounded by onchain gaslimits, i.e. there is no necessary per-tx onchain footprint. You only sync heavily unbalanced channels to L1, and a million of $1 payments can remain entirely offchain as long as they net-out each other to zero. 

In other words XLN can survive with expensive CALLDATA (e.g. on Ethereum Classic) and/or low gaslimits per block, while rollups will continuously require cheap CALLDATA and further L1 block gaslimit increase to scale

2. channels have perfect data availability because they sync current L2 state to L1 state, while rollups simply flush L2 history  to L1 history as CALLDATA. There is no hard proof that re-genesis tricks on ETH or other EVM chains won't destroy historical CALLDATA at some point.

3. while rollups are fully EVM generalized, payment channels support paying/swapping/borrowing and lending (using Rainbow idea) and those are probably 90% of L1 use cases at the moment. 

# Why is XLN on the hackathon?

This project is NOT eligible for any prizes as it is built on an existing codebase. However I couldn't resist to participate in something called "Scaling Ethereum" and get feedback from Layer2 aficionados in the judges! Thanks in advance for taking your time!

XLN: Extended Lightning Network

We aim to create an integration between e-commerce platforms such as Teiqui.com or Shopify with DeFi products such as Yearn Finance, Compound, others... 

The main goal is for these platforms to provide easy access to their users, in order to obtain yield in different products, such as stable-coins, or any other cryptocurrencies. 

The vaults will be implemented to interact with other networks vaults to obtain the highest APY possible for a specific token/coin. Creating a multi-chain yield aggregator starting with polygon.

2pi.finance

More and more awesome dapps pop up every day. They run on different chains to avoid the high gas fees of ethereum mainnet. We want to use all of those tools, but it is hard to get there. It is difficult to keep track of how much of your money is currently in which chain and a lot of work to move the right currency where you want to use it. We build a tool overcome these challenges.

Layer2 DEX Aggregator

Boson Protocol allows decentralized commerce using NFTs encoded with game theory.
When a seller deploys the same offer on different Layer 2 chains, the  supply quantity of items for sale needs to be managed across multiple chains.
So we need a cross-chain inventory synchronization mechanism.

If the seller has a quantity of 10 items, he could say “I want to sell 5 on Polygon and another 5 on Arbitrum”. In that way, the buyers can actually choose on which L2 chain they want to buy. The reason they would do this is because some people are more familiar with one L2 chain than another. They might be more comfortable using Polygon, or Arbitrum, depending on their experiences or depending on which chain they own tokens to pay the gas.The problem is that if there are more purchases on one L2 chain than the other, it would lead to reduced supply quantity on one chain and a high supply quantity on the other, and vice versa.

Boson Cross-Chain

This project provide the platform where user can buy and sell bonds.  we use onchain orderbook to execute the trade like OasisDex . it implements a sorted order book by providing additional sorting structure.
price of particular offer is stored in the list, these prices are ranked according to price offered.
when buyer buy the bond at certain price, if this price is matched with list then trade get executed .

After buying of bond user is directed toward indenture  page, here user is required to submit their signature to download indenture document which provide the details like coupon rate, principal amount  , maturity etc.

user have a option to upload these document on IPFS, for storing document we have use ipfs_http_client package

mBondX

We brought Tornado Cash's privacy to Arbitrum's Layer 2 to enable quick, cheap, and private transactions for the Ethereum blockchain. We utilized the work done by Tornado Cash to bring their ZK-SNARK technology to Layer 2 and created a UI with react to interact with these contracts on Arbitrum's Kovan Testnet.

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