Guarda Zcash light wallet

[AndrewGuarda]

Guarda Wallet team application for Zcash foundation grants 2017Q4

Motivation and overview

We are a group of blockchain enthusiasts with background in software development and product management. We have a distributed team from EU, Russia and Ukraine. At the moment we have experts from IT, fintech, blockchain, security, marketing, design, UI/UE.

Recently we have united together to develop a project called Guarda. Mobile cryptocurrency wallet which would make using any cryptocurrency easy, accessible and secure.

Our wallet for the first currency was launched this week in Google Play

Zcash is one of our favourite blockchains thanks to technological supremacy, great development team and clear value proposition. As a team of crypto enthusiasts we believe in anonymity as key feature of decentralized currencies and blockchain technology overall. Zcash already is in our development roadmap. However development of Zcash light wallet is yet an issue due to the lack of open source mobile light wallet implementations.

Technical approach

We are guided by several core principles:

• Building trustless solutions. If customer wants to rely on other cryptocurrency node he\she can type in this information.
• Multicurrency approach. We thoroughly choose best cryptocurrencies and willing to support them all.
• Respect customers privacy. We do not require any KYC or customers data. No registration is required as well.
• Never touch customers funds. The proposed wallet is a light wallet allowing customer manage his\her keys himself
• Never touch fiat. Purchase of cryptocurrencies will be delivered in collaboration with professional payment gateways.

In general the wallet consists of the following parts:

• Server side node Blockchain community developed solution. Open-source and distributed free
• Lightwallet library This allows you to work with the cryptocurrency blockchain, without the additional overhead of having to write your own integration code for the platform. Usually the library interacts with the server side node through JSON RPC. As we are applying for a grant we believe this part of our work should be open sourced and available for public on a royalty free basis.
• GUI layer Customer experience oriented graphic user interface running on mobile operating system of the mobile phone.

High level architecture can be described as follows:

Network HL architecture:

We have three basic stages for the wallet implementation.

• Everything starts from the own blockchain nodes deployment. We have own primary and backup nodes for the wallet support. In addition we offer a range of third party nodes that can be applied by user. We are using sophisticated proxy for the node balancing in order to get up-to-dated blockchain status.

• The next step is mobile client library implementation. It is used by mobile wallet to manage transactions and abstract blockchain, security, cryptography layer from GUI developers.

• The last stage is the design implementation of mobile application. We are thriving to use trendy and cozy interfaces in our wallets to provide best customer experience.

We are developing light wallet which means that user private keys are always under the user control. The private keys are always on the customer device and managed only by user. The wallet signing a transaction on the device side and transmit the signed transaction over Internet using ssl to blockchain node.

The Guarda wallet implemented functions are:

• send coins
• receive coins
• exchange cryptocurrencies to zcash,
• PIN code app protection

To be implemented in following two months (before Zcash wallet to be released):

• purchase zcash for the fiat . Our committed partners for card transactions and SEPA payments are available to be disclosed upon request from Grant Review Committee.
• other node usage
• mnemonic phrase
• password encrypted keyfile

Team background and qualifications

• Paul S., CEO, has three years experience in blockchain, 10 years in fintech. Certified banking cards security and business expert. Launched over 6 successful projects within last three years. Paul interests are: cryptocurrency exchanges, wallets, smart contracts, oracles.
• Ondrej H., product manager, has 15+ experience in IT product management. Has in the portfolio projects from mobile ads, SaaS enterprise solutions, high load IT solutions, mobile app development and production.
• Vlad A., senior Android developer, 7+ years of mobile development
• Valentin S., senior Android developer, 6+ years of mobile development
• Alex N., senior iOS developer, 6+ years of mobile development
• Roman L., senior backend developer, expert in blockchain, has 3+ years of experience for blockchain development, cryptocurrency mining, etc.

Evaluation plan

We have quite tiny and reasonable schedule for the wallet implementation. The distributed team with a variety range of professionals gives us ability to launch in the parallel main project phases: blockchain node deployment, mobile library and wallet GUI development. We are using agile approach with continuous delivery, so in any time of moment we are ready to present our progress and performance to the Grant Review Committee.

Security considerations

Security is our priority. The light wallet approach itself is our vision for the secured blockchain wallet. The customer private keys are the most important and sensitive aspect. We store keys in OS secure storage in an encrypted form. We are using additional product features to increase the product resistance for the attacks. The team has already implemented PIN-code for the wallet access, password keyfile encyption is expected by the middle of October. At the node side we are using network security tools, like a WAF with ML.

Schedule

We are estimated the whole zcash wallet duration as 11 weeks:

• 1 week hosting & node setup, UE
• 2 week node proxy, setup net security tools, mobile library, UI mock ups
• 3 week mobile library development, UI prototyping
• 4 week mobile library development, UI design
• 5 week mobile library development, mobile app implementation, UI design
• 6 week integration with third parties services, mobile app implementation
• 7 week mobile app implementation
• 8 week alfa release, QA, bug fixes, mobile app implementation
• 9 week QA, bug fixes, beta-release
• 10-11 week Project Risks worked

Budget and justification

We have estimated preliminary costs estimation for 60K USD for the project that will cover almost all issues.

Facebook Twitter email github

[anna-spada]

Hy everyone! It seems that a part of the communication has been lost somewhere in the middle. We've synced up with Sonya last week but I'll also post a brief update here just to make sure that we're all on the same page:)

1) Zcash android app for T-addr is up and running. However, after the fork we experience some difficulties with sending transactions in the Android app. We're fixing it now and hopefully, we'll upload the updates here soon. 2) We’ve also added Zcash support on our web-wallet and on desktop wallet app. Web and desktop versions are working fine (including transactions) and we see the growing number of users, which is good:)

As per the Z-addr support: the status has not changed much since April: after a discussion with the community and foundation members we decided to wait with Z-addr implementation till Sapling is released. Thus we can make Z-addr app more suitable for usage on mobile devices with limited capacities. We'll keep you updated on this.

[AlekseiSmirnov]

Now it's May 2019 and still, there is no light Zcash wallet with support of Z-addresses. Now I understand why Zcash price constantly descends. Zcash is known for its privacy but no one can flawlessly use it

[mineZcash]

@AlekseiSmirnov , they are working on it:

https://twitter.com/GuardaWallet/status/1122944035877003265?s=19

[AlekseiSmirnov]

@mineZcash I'm not saying about Guarda. I mean in general. I'm a tech guy and couldn't perform shielded transaction within 1.5 hour. There are no light wallets that work. Wallets with the embedded node (like zecwallet) are crashing. Really poor experience. Mass adoption of zcash is just not possible until you give people normal user-friendly tools to use it.

[arielgabizon]

From the tweet looks like good progress of Guarda. Hopefully, the state of affairs of easily using z-addrs will change soon. Though Guarda don't mention it in the tweet, I'm guessing they only refer to sapling z-addrs.

[arielgabizon]

I wonder though, how they deal with scanning the whole blockchain with the viewing key that @AndrewGuarda mentioned above was the hardest part. This specific part is not easier for Sapling compared to Sprout.

[franksimon90]

Is there any issue with the fee calculation? I have funds available on the Android app on BTCH, but I can't transfer those to any wallet because the calculation fee always fails, I can't even make an exchange because the wallets view is always empty. Is there any place where I can submit the logcats, or keep track of those bugs?