We are proud to announce one of the most important milestones of 2019 for Tixl. Under the codename “Altona” — named after a beautiful district of Hamburg, and the home of Tixl — we have released the first version of the Tixl core as Testnet release candidate.

Photo by Jonas Tebbe on Unsplash

TL;DR How can I use it?

Go to https://wallet.tixl.dev/ Click on the RECEIVE button and copy your address. Click on the link below your balance, this will take you to our Telegram bot. Send your Tixl Testnet address to the bot and wait a moment.

Optional:

You can see transactions on https://explorer.tixl.dev/

You can use another browser or an incognito-window to launch a second wallet to test the SEND feature.

feature. Append ?reset to the wallet address to reset your wallet and get new keys (test funds are lost!)

What is contained in Altona?

Altona already contains the most important aspects of the planned Tixl core. A special focus has been put on cryptography and persistence, as well as the consensus protocol. The two aspects of privacy and speed of the web-wallet are not yet fully developed in Altona - these will be the focus of the next releases. Below, we look closer at the technology:

Altona’s Consensus Protocol

As known, the Tixl backend uses the Stellar Consensus Protocol (SCP) to check whether transactions are valid or not. Our implementation is not a fork of the Stellar network but, instead, a custom implementation. Even though the process is already solid, we are conscious of two things:

We may have to reconsider the programming language of parts of our implementation. At the moment, the implementation is based on Typescript and a Node.js runtime. Since Typescript is compiled to JavaScript and JavaScript is not the most efficient language for a back-end, we might translate parts to other languages. We don’t see this as a key criterion for the mainnet as long as JavaScript is not a critical performance bottleneck. Even though we are proud of our team’s programming skills, a critical system like the consensus must be reviewed and audited by at least one or, ideally, two independent parties. This is one of the main drivers of our fundraising activities - so that we have the financial resources to contract high-quality companies to assist.

Altona’s Privacy Implementation

The Altona Testnet is already partially private. For each transaction, amounts are encrypted via the quantum secure cryptosystem NTRU. This is also the reason for the long addresses that exist in the Testnet. We have found a way to reduce the address size and will ship this with one of the next releases. Additionally, we have ideas for simplifying the usernames for Tixl. By comparing amounts, senders and recipients are not private at the current time. This is because we have technically implemented Stealthchains, but the wallet is not using them yet. Cut-through transactions are also not part of this release.

On balance, we believe it’s better to provide the first release before we have every aspect implemented and working perfectly. By doing this, we can use the feedback collected to provide frequent optimized releases in the future.

Altona’s Data Structure

The Altona release provides the full data structure needed for basic Tixl transactions. The blocks of the different chains are stored in a SQL database. The decision to use SQL in the future has not been finalized but, for the first release at least, using SQL was the most efficient option. The following screenshot shows a table storing Tixl blocks.

Tixl Altona Testnet Database Extract

Altona’s Wallet

The picture below shows a screenshot of the Tixl Testnet web wallet. It can be accessed in a desktop browser and also on mobile devices. The responsiveness is not yet optimal, and we’ll be working on that over the coming weeks. The wallet can be found here, and you are very welcome to report bugs and feedback on this repository.

At the moment, the functionality of the wallet is very basic. As soon as you open the wallet it will automatically create a private key for you and write an opening block to your Accountchain. In our Testnet, the private key will simply be stored in the local storage of your browser. As there are no real MTXL on the testnet, there is no backup functionality for the private key at this stage.

You can claim some free test tokens through our special Telegram bot. The bot needs your address which you can copy after clicking the RECEIVE button of the web wallet. The amount of test tokens is random, and tokens can be claimed every 60 minutes. When you have the tokens, play with the wallet and send some test tokens to your friends and family 🙂

If you want to reset your wallet, append ?reset to the URL (address field of your browser) and hit the Enter key. As soon as the page reloads, your wallet will be reset.

Tixl Altona Testnet Wallet

Altona’s Explorer

To make what happens on the Tixl network more transparent, we have launched the Testnet explorer. Currently, it will show you the following information:

The slot number which represents how many rounds the consensus algorithm has completed since the start of the Testnet.

The total supply of all Tixl tokens, which cannot increase.

The number of validator nodes currently participating in the consensus algorithm.

The number of transactions per hour.

A list of blocks that have been validated by the consensus protocol. These blocks currently have three types: Send blocks to indicate that someone has submitted a TXL transaction to the network. Receive blocks to indicate that somebody has claimed the tokens from another Send block and written them to their Accountchain (later Stealthchain). Lastly, Open blocks that indicate when somebody created a new account.

blocks to indicate that someone has submitted a TXL transaction to the network. blocks to indicate that somebody has claimed the tokens from another Send block and written them to their Accountchain (later Stealthchain). Lastly, blocks that indicate when somebody created a new account. A list of slots which shows how many validators have participated in a slot and how many transactions have been processed in a slot.

Explorers are not ideal for providing detailed information with private transactions. However, since we will offer optional transparent transactions in the future, it still makes sense to have one. In addition - for your personal transactions and for the network health, the explorer provides a good information base about the status of the consensus.

Tixl Altona Testnet Explorer

Altona’s Transaction Speed

A transaction from A to B, consisting of a send block and a receive block may take from 10 seconds to 25 seconds in the web wallet. There are multiple factors which influence the transaction time:

The consensus takes 5 seconds. If your transaction is submitted straight after the round has started, the transaction will take nearly 10 seconds to be confirmed.

There are two blocks (send and receive), each requires confirmation by the consensus.

The wallet needs to fetch the data from the blockchain and does so by polling in an interval, so the interval time also adds to the total time taken.

We are already working on ideas and concepts to further reduce the transaction time in future releases.

Known Temporary Limitations

The fact that we only use the Accountchain to send and receive funds in this release, combined with the web-wallet not writing to a local chain (instead fetching it from the servers, repeatedly), can lead to the following problem: If your wallet issues two transactions in a short time-frame, they will both reference the same block, which will lead to the rejection of the second transaction. For example, if your wallet issues a receive block for a transaction - where someone sends you some TXL and one second later you issue a send block - the send will fail. You can circumvent this by waiting until you don’t have a “pending” block in your wallet.

Another current limitation is that rejected transactions won’t show up in the wallet, or the explorer. We are working on error handling that will provide more information to the wallet user.

Disclaimer:

All tokens on the Testnet are worthless. In addition, we may reset the entire network for a restart without warning, at any time. Given the Testnet is under active development, we may also reset the network at any point - which resets all funds - but you can claim new test tokens via the Telegram faucet at any time.

About Hamburg-Altona

Altona is located in the west of Hamburg, only a few minutes away from the city center. Supposedly, the name Altona comes from the Hamburg merchants who considered their rival to the west ‘all zu nah’ (‘far too close’). Nowadays Altona is known as a lively neighborhood with a slightly alternative lifestyle with many students, and for the long-distance train station. Read more about Altona on hamburg.com