Lior Yaffe: Introduction to Transaction Vouchers

wallet voucher exchange blockchain ardor

One of the most annoying and error prone aspects of crypto trading is the process of deposits and withdrawals from exchanges.

Take a look at this Bittrex deposit dialog for Ardor

Let’s think together about all the things which can go wrong when you send your precious Ardor tokens from your account to Bittrex.

  • You can mistype the account address — not a real risk since the account address has internal error correction.
  • You can forget to include the message or mistype it. Your funds will still go to Bittrex, but Bittrex won’t be able to credit your account, so expect a looooong discussion with their customer support team.
  • You may mistakenly deposit Ardor into an Ignis address or vice versa. Again, expect a looooong recovery process for your funds.
  • A deposit from another exchange to Bittrex or from Bittrex to another exchange may not specify a message, so it will get lost as well.
  • Even if your deposit does specify a message, some exchanges expect plain text messages while you may send it encrypted or vice versa.
  • But things can get much worse …

    6. What if instead of connecting to Bittrex.com, you were tricked into connecting to, say, Bitrex.com? Let’s assume for a moment it’s a phishing site aimed to steal your funds, if you don’t notice the difference you will happily deposit into the address they provide you, losing all your tokens.

    Exchange withdrawal process suffers from similar problems as well. For example, what if you withdraw your funds to a newly created account and then forget the passphrase? Say bye bye to your precious tokens.

    But even just sending crypto between friends or businesses is risky. When you email your account address and amount without any authentication, what if someone intercepts this email and changes the address or amount? Can we do better? Yes we can!

    Our Solution — Transaction Vouchers

    Think about transaction vouchers like an invoice. A request to pay a certain amount to a certain address signed by the private key of the recipient. The idea is based on the Bitcoin Payment Request proposal but using the rich functionality of Ardor/Ignis, we can do so much more.

    The voucher itself is a JSON format, composed of the transaction json, transaction bytes and a digital signature of the transaction bytes.

    Say, Alice wants Bob to pay her 100 IGNIS. She logs into the Ardor wallet using Bob’s account and sends payment as if she were Bob. Of course, she does not have Bob’s passphrase, so she cannot submit the transaction. Instead, she signs Bob’s payment using her passphrase and generates a voucher.

    Notice the Voucher checkbox

    Alice then downloads the voucher and emails it to Bob.

    The Voucher Generated by Alice

    Bob receives the voucher and loads it into the Ardor wallet. The Ardor wallet automatically verifies that the voucher signature is valid and that the voucher bytes are a correct representation of the voucher transaction JSON. After validation succeeds, the wallet presents Bob with the request, it shows Alice’s address as the recipient, the amount she wants him to pay, any attached messages and any other transaction parameters.

    Bob loads the voucher into his wallet

    All Bob needs to do is validate the data, sign, and submit the transaction using his passphrase.

    Bob is sure that the voucher is authentic, since any changes an attacker might have done to it, will prevent it from being validated by the wallet. Bob is also sure that Alice knows her account passphrase since otherwise she couldn’t have generated the voucher in the first place. Finally, both Alice and Bob now have a document for their bookkeeping, proving to each other and anyone else that the payment was requested.

    You can watch me demo the concept in this video from a workshop I ran recently in Norway.

    Now think about the Bittrex exchange deposit process. Instead of asking you to send tokens to an address with an attached message, Bittrex could generate a voucher file that you can import into the wallet which contains their deposit address and the message they want you to send them. Perhaps they will also let you scan a QR code with this data. All you’ll need to do, is load this voucher into your wallet, double check the recipient address with the well known Bittrex account, sign, and submit the transaction.

    But vouchers are not limited to payments. They can be used for any transaction type supported by Ignis. For example Bob wants to delegate a poll vote to Alice. Alice logs in as Bob and generates a voting voucher, then sends it to Bob by email and asks him to sign and submit it.

    Or, as another example, Charlie, a forging pool operator, wants Bob to lease his balance to his pool. Again he performs the leasing request on behalf of Bob, then sends a voucher that Bob needs to sign and submit.

    However, it’s important to note that vouchers do not depend on the wallet. Alice and Dave can generate the voucher using an API and Bob can validate and sign them using an API as well. All the processing can even be off loaded to lightweight contracts since vouchers can be used to trigger lightweight contracts and lightweight contracts can generate vouchers. More on this in my next article.

    Original article was created by: Lior Yaffe at medium.com

    Disclaimer: This article should not be taken as, and is not intended to provide, investment advice. Please conduct your own thorough research before investing in any cryptocurrency or ICO.

    One more thing you may be interested in:

    Interested in Cryptocurrencies and ICO's?

    Follow our telegram channel for daily cryptomarket reports!

    Join @cointrends

    Stay on top of Altcoins and ICO trends.

    Subscribe to our free Weekly Cryptomarket report

    Delivered once a week, strongly to your inbox.

    Subscribe to our mailing list
    May 16, 2018
    May 15, 2018

    Lightweight Contracts Design

    Architecture of the Ardor Lightweight ContractsLightweight Contracts Design. Image credit: Fleur Treurniet from Unplash.See all previous lightweight contracts articlesThe design of the Ardor Lightweight Contracts feature continues to progress rapidly. I would like to share some of the design...

    From: Lior Yaffe
    May 13, 2018

    Lightweight Contracts Articles

    Lightweight ContractsLightweight Contracts FAQMore Advanced ContractsOracle Contracts on ArdorArdor Lightweight Contracts Use Case

    From: Lior Yaffe
    April 24, 2018

    Ardor Lightweight Contracts Use Case

    Ardor Lightweight Contracts Use Case. Credit image: Joey Huang from UnsplashWe can now solve the ARDR paradox using a simple contractOne of the most annoying problems for new users of Ardor is that you cannot buy the ARDR parent chain token unless you already own ARDR tokens to pay the...

    From: Lior Yaffe
    April 20, 2018

    The NXT wallet is the ICO platform.

    The NXT wallet is the ICO platform. You can develop a plugin on top of it with your own user friendly UI.

    From: Lior Yaffe
    April 18, 2018

    Oracle Contracts on Ardor

    Oracle Contracts on Ardor. Image credit: Luca Laconelli from Unplash.Contracts which load information from external sourcesAn Oracle in the context of a blockchain, is a process which retrieves information from external resource and registers it on the blockchain. Other contracts or online...

    From: Lior Yaffe
    Upcoming ICO's
    This week overview
    Token Name Starts
    Yumerium (YUM) logo Yumerium (YUM) 1 days
    Acorn Collective (OAK) logo Acorn Collective (OAK) 3 days
    Tradelize (TDZ) logo Tradelize (TDZ) 6 days
    Scanetchain Token (SWC) logo Scanetchain Token (SWC) 6 days
    Kepler (KEP) logo Kepler (KEP) 6 days
    Cryptocurrency rates
    *Last hour average price&change
    Coin Name Price Hour
    Bitcoin logo BTC $8015.33 -0.32%
    Ethereum logo ETH $645.293 -0.46%
    Ripple logo XRP $0.64306 -0.64%
    Bitcoin Cash logo BCH $1141.22 -0.25%
    EOS logo EOS $12.2787 -0.49%
    Litecoin logo LTC $128.348 -0.39%
    Cardano logo ADA $0.220837 -1.89%
    Stellar logo XLM $0.299053 -0.83%
    Tronix logo TRX $0.0746523 -0.74%
    IOTA logo IOT $1.62172 -0.99%
    NEO logo NEO $57.2254 -0.56%
    DigitalCash logo DASH $358.953 -0.41%