[ANN] Zcoin (XZC) - Implementing Zerocoin technology for financial privacy

[zcoinofficial]

Bounty for MTP Audit ($10,000) and MTP Implementation ($2,500)



We are announcing bounties for MTP audit and MTP implementation.

MTP (Merkle Tree Proof) is a new proof of work algorithm that was presented at the USENIX Security Symposium 2016 and has attracted substantial attention from the cryptocurrency and academic community. To further encourage research and scrutiny into MTP, we are sponsoring two bounties.

MTP Audit Bounty: 10,000 USD Total
MTP Implementation Bounty : 2,500 USD TOTAL

Deadline of submission is 30 September 2017 but remember it is better to submit early as duplicates are not rewarded.

Further information about rules and bounty distribution can be found in our blog post:
https://zcoin.io/bounty-mtp-audit-10000-mtp-implementation-2500/

[zcoinofficial]

Quick Dev Update - 27 July 2017
Poramin should be pushing updates to MTP soon to resolve the issues found by mbevand in the bounty.

Djm34 and Leorei have rewritten the rpcmining interface so that it now accepts the larger proofs for the miner.

Aizensou's core upgrade code is complete and testing Zerocoin functions is underway but looks good for the moment.

Core upgrade seems to have improved sync speed and reliability greatly.

[wellst1]

We love Z

[zcoinofficial]

Core Upgrade - 13 August 2017

We are happy to announce that Zcoin is almost ready to be deployed on Bitcoin Core 0.13 and will be released soon. One of the benefits of being on a Bitcoin base means we can adopt benefits of Bitcoin improvements relatively easily.

The upgrade of the Bitcoin Core from 0.8 to 0.13 is a culmination of several months of work and improves on many aspects of Zcoin with node connection reliability and sync speeds drastically improved. Sections of the Zerocoin code had to be rewritten to accommodate the core upgrade and opens the door to a whole range of improvements that we can adopt from light wallets to hardware wallet integration.

Some other improvements from the core upgrade:

• Support for blockchain pruning
• TX malleability fixes
• Memory usage optimizations
• Privacy: Stream isolation for Tor: This release adds functionality to create a new circuit for every peer connection, when the software is used with Tor. The new option, -proxyrandomize, is on by default.
• Hierarchical Deterministic Key Generation
• The core upgrade also allows us to work on implementation of Znodes. We will post an update once we upload the code on Github and also have the binaries available.

MTP

We are very pleased that has been a lot of academic debate on MTP the first being Dinur & Nadler's paper which we had patched a quick fix to it as a temporary solution. It was this paper that prompted us to launch our USD10,000 MTP Audit and USD2,500 MTP Implementation bounties to further encourage research into MTP and also prompted a slew of changes to our MTP code.

Since then, we have also been given a draft copy of research from Fabien Coelho at Zeronote Skunkworks that brings new memory hard PoW proposals to improve MTP and to counter known attacks to the scheme and is currently awaiting feedback from the authors of MTP.

We have also received on the 11 and 12th August several submissions from Marc Bevand to the  MTP bounty which require further investigation and also further scrutiny into the proposed fixes. You can view his submissions here which are currently being validated.

Alex Biryukov (one of the authors of MTP) has mentioned in light of Dinur & Nadler's paper, that MTP needs further work  and we have been informed that they are planning to continue work on MTP in September and October which aims to address these new academic papers and research and to further improve on MTP including proof size optimizations.

As such, although we are technically ready to migrate MTP in its current form to mainnet, in light of the above discoveries, the responsible thing to do is to hold off on deployment on mainnet until the revised paper is out and there is confirmation that the attack vectors are closed as opposed a temporarily patched MTP that will be almost certainly be changed again. We apologize for the late notification but it was not a decision we took lightly but we are thankful that the research came to light before deployment of MTP on main net.

MTP in its current form is completely functional and continues to be able to be tested on our Testnet. You can compile zcoind from our Github mtptest branch and also mine with its inbuilt miner. You can also ask from our Slack if you need binaries to the MTP testnet or get some testnet ZCoins.

You can view our Testnet explorer here: http://testnet.zcoin.io:3001/

We remain committed to MTP as long as it remains a viable PoW and we continue to refine our code to make it easier for third parties to work and read with. We thank you for your patience and understanding especially when developing cutting edge technology.

[alucard06]

very good

[zcoinofficial]

Core Upgrade - 13 August 2017

We are happy to announce that Zcoin is almost ready to be deployed on Bitcoin Core 0.13 and will be released soon. One of the benefits of being on a Bitcoin base means we can adopt benefits of Bitcoin improvements relatively easily.

The upgrade of the Bitcoin Core from 0.8 to 0.13 is a culmination of several months of work and improves on many aspects of Zcoin with node connection reliability and sync speeds drastically improved. Sections of the Zerocoin code had to be rewritten to accommodate the core upgrade and opens the door to a whole range of improvements that we can adopt from light wallets to hardware wallet integration.

Some other improvements from the core upgrade:

• Support for blockchain pruning
• TX malleability fixes
• Memory usage optimizations
• Privacy: Stream isolation for Tor: This release adds functionality to create a new circuit for every peer connection, when the software is used with Tor. The new option, -proxyrandomize, is on by default.
• Hierarchical Deterministic Key Generation
• The core upgrade also allows us to work on implementation of Znodes. We will post an update once we upload the code on Github and also have the binaries available.

MTP

We are very pleased that has been a lot of academic debate on MTP the first being Dinur & Nadler's paper which we had patched a quick fix to it as a temporary solution. It was this paper that prompted us to launch our USD10,000 MTP Audit and USD2,500 MTP Implementation bounties to further encourage research into MTP and also prompted a slew of changes to our MTP code.

Since then, we have also been given a draft copy of research from Fabien Coelho at Zeronote Skunkworks that brings new memory hard PoW proposals to improve MTP and to counter known attacks to the scheme and is currently awaiting feedback from the authors of MTP.

We have also received on the 11 and 12th August several submissions from Marc Bevand to the  MTP bounty which require further investigation and also further scrutiny into the proposed fixes. You can view his submissions here which are currently being validated.

Alex Biryukov (one of the authors of MTP) has mentioned in light of Dinur & Nadler's paper, that MTP needs further work  and we have been informed that they are planning to continue work on MTP in September and October which aims to address these new academic papers and research and to further improve on MTP including proof size optimizations.

As such, although we are technically ready to migrate MTP in its current form to mainnet, in light of the above discoveries, the responsible thing to do is to hold off on deployment on mainnet until the revised paper is out and there is confirmation that the attack vectors are closed as opposed a temporarily patched MTP that will be almost certainly be changed again. We apologize for the late notification but it was not a decision we took lightly but we are thankful that the research came to light before deployment of MTP on main net.

MTP in its current form is completely functional and continues to be able to be tested on our Testnet. You can compile zcoind from our Github mtptest branch and also mine with its inbuilt miner. You can also ask from our Slack if you need binaries to the MTP testnet or get some testnet ZCoins.

You can view our Testnet explorer here: http://testnet.zcoin.io:3001/

We remain committed to MTP as long as it remains a viable PoW and we continue to refine our code to make it easier for third parties to work and read with. We thank you for your patience and understanding especially when developing cutting edge technology.

[zcoinofficial]

Some development updates:

Poramin has just pushed in our private repo the fixes needed to implement the Zerocoin improvements and fixes.
Tim Ruffing has pushed the the fixes on libzerocoin as well.
Tim is now looking through Poramin's code to ensure it works as intended and Aizensou and SN are working to integrate the Zerocoin improvements into the new core upgrade 0.13.

There will be an academic paper published as well to detail these fixes so that other Zerocoin implementations (if there are any other original implementations) can fix them independently and contribute to Zerocoin research.

Our new Zerocoin code will be open sourced in due time but may not be done immediately.

We are still weighing our options here as a lot of hard work and resources was put into this and all these fixes are backend which are not quite visible to the user but are important to improving the Zerocoin protocol and its security.

[zcoinofficial]

Zcoin Core Upgrade to 0.13 is here

We are very excited that Zcoin on the new 0.13 core is finally here and greatly improves Zcoin’s performance, network reliability and feature set. The codebase has undergone huge changes and represents a strong foundation to build all our improvements on including Znodes and Zerocoin improvements. We had some delays due to incompatibilities caused by the huge jump from Bitcoin core 0.8 to 0.13 in many aspects. We thank you for your patience!

We highly recommend upgrading to the latest Zcoin release as soon as possible.

Key highlights of the Core Upgrade

• A fresh sync used to take several days and has been brought down to 2-3 hours.
• Full TOR support with hidden services and TOR stream isolation. With TOR stream isolation,  every outgoing connection will (potentially) go through a different exit node. That significantly reduces the chance to get unlucky and pick a single exit node that is either malicious, or widely banned from the P2P network. This improves connection reliability as well as privacy, especially for the initial connections.
• Greatly improved node connectivity, reliability and communication between nodes
• Pruned blocks support allows you to only keep a much smaller set of data taking up only a fraction of space on your hard disk.
• Improved transaction fee system that will dynamically adjust fee where required.
• Allows much easier integration with hardware wallets like Trezor and Ledger of which work is in progress.
• Zerocoin mints and spends are more reliable

Important Instructions when Upgrading to the new Zcoin wallet
As this is a massive code change, a few steps need to be taken to update your existing installation to the new wallet.

Before upgrading to Zcoin 0.13.2.4:

• Backup your wallet.dat to a new location or do so by going to File > Backup
• Browse to your Zcoin directory
• Linux ~/.zcoin
• Mac ~/Library/Application\ Support/zcoin/
• Windows %appdata%\zcoin
• Delete all files and directories there except wallet.dat
• Run the new executable binary

Note: znode.io can be used but you will get a message that you will need to rebuild the database. Just say yes. If you are using command line, please use the -reindex flag.

If you get an error "Error loading block database." it means you didn't clear your Zcoin directory's files as above.

MD5 Digest:
Windows: 0a3fc1086c759e21fb58002fe9990552
Mac: e6304058b22a2dd31ebaf0b999937a86
Linux: 571849b3af8d77e22b6d32dadc5a69a4

Known Bugs:

• Do not do Zerocoin spend transactions until your mint has 7 confirmations. Currently GUI allows it with 6 confirmations only. This will be fixed in next release.
• When doing Zerocoin mint or spend, make sure you have good connectivity to nodes and do a backup before and after you do a mint just to be on the safe side so you can always restore if it doesn't go through. We are investigating some edge cases where the mints/spends don't confirm. This will improve when more nodes upgrade to the new version.

What about Bitcoin Core 0.15, why did you pick 0.13?
0.8 to 0.13 was a massive leap but the development team decided to stick to 0.13 in the interest of getting out a release as soon as possible to improve the user experience as when evaluating, the code change from 0.8 to 0.15 was too great. The movement from 0.13 to 0.15 is also another huge code revamp and although of course brings some benefits, does not warrant the time investment at this stage of development as they centered around scalability improvements which aren’t a pressing issue with our current transaction volume.

We will focus on our other milestones in our roadmap before relooking into another core upgrade though it is definitely on the cards. It is to be noted that most altcoin projects are based off earlier Bitcoin core bases due to the immense work involved (for e.g. Dash/PIVX at 0.10, Zcash at 0.11).

We will cover what Zcoin will be working on next in development in our next blog post.

Download link
https://github.com/zcoinofficial/zcoin/releases/tag/v.0.13.2.4

Full blog post on Zcoin.io

[zcoinofficial]

Zcoin Dev Update 19 September 2017: Znodes, GUI, libzerocoin, MTP and ZEth

What’s Next in Development?
After the completion of the Zcoin core upgrade, this opens up a range of improvements that the team can now work on.

libzerocoin improvements
With the assistance of Tim Ruffing, he has identified several fixes that are required in the software library that underpins Zerocoin and Poramin has implemented them into our codebase based on 0.8. Work is being done to port these fixes over to the new core 0.13 and we intend to roll this out by the end of the month or early October. We believe this is the first major improvement to libzerocoin in a long while and represents a major step forward in providing a secure Zerocoin protocol. Our next step after implementing these fixes is to do a code cleanup and refactor of the Zerocoin code to make it easier to audit.
As our commitment to open source, we will release the source code for this that will allow other projects that are using Zerocoin to secure their own Zerocoin implementations. We hope other projects can contribute to the development of Zerocoin as well.

GUI Revamp
Besides the backend, we understand the importance of having a aesthetically pleasing graphical interface especially when it relates to the use of Zerocoin. Our next task is making the wallet easy and intuitive to use.
We also will have some commands to recover Zcoin that has been stuck in unconfirmed spends from the previous version so make sure you don’t delete your old wallets with funds. As long as you have the wallet where you did the original mints, your funds are safe.

Znodes
At the same time, work will begin on Znodes, the long awaited update that allows incentivized nodes to support the Zcoin network and makes Zcoin into a hybrid Proof of Work and Proof of Stake system. Znode owners will earn a proportion of the block rewards as an incentive to maintain a full node, keep it updated and maintain the network. A certain number of Zcoin will be required as a ‘collateral’ to start a Znode to discourage Sybil attacks. This number will be announced as we come closer to launch but we aim to achieve a balance between allowing people to participate while maintaining a decent profitability for node owners to keep them sufficiently incentivized.

Reusable Payment Codes / Stealth Addresses
We are considering between either implementing BIP47 Reusable payment codes or Stealth Addresses. The benefit of Stealth Addresses is that it can be implemented very quickly given that Poramin was actually the first developer to successfully implement it in a QT wallet in Vertcoin. However, BIP47 has certain advantages over Stealth Addresses in that it can be used in light wallets and they are not distinguishable from regular Zcoin transactions however thought has to be given to how to implement it in the UI and also development will take longer.
Currently there are only two BIP47 implementations out there being the Samourai wallet and the Dark Wallet while stealth addresses are well understood and implemented in many coins.

MTP Porting to new codebase
We will port our existing MTP code to the new 0.13 codebase so that we are ready to implement MTP as soon as we can after the researchers Alex Biryukov and Dmitry Khovratovich publish their revised paper with improvements to MTP both in the areas of security and performance. We will only be able to comment on how long this will take when extended a copy of the revised paper which is expected sometime in October.

Proof of Concept Ethereum Zerocoin mixer
Tadhg is currently well underway with coding of his smart contract for ZEth (Zerocoin mixing on Ethereum). We hope to deploy a functional proof of concept mixer for Zerocoin on Ethereum soon. We hope that this project will bring greater recognition of our project with the Ethereum community along with opening up synergies between the two currencies together with cross atomic swaps which allow decentralized conversion between Zcoin and Ethereum and vice versa.
Poramin and Riordant will be attending Devcon3 in November 1-4 and aim to have the proof of concept smart contract ready by then.

Hardware Wallet Integrations
Community members have started integrating Zcoin with Trezor and Ledger. The Bitcoin core upgrade now makes their task a lot simpler and hopefully will accelerate development here.

https://zcoin.io/zcoin-dev-update-september-2017-znodes-gui-libzerocoin-mtp-and-zeth/

[kingscrown]

XZC will have many updates soon ie masternode (called znodes) and looks solid at current price as floor.
I have made a wirteup of what i think of current state and whats coming for it in future -
http://fuk.io/xzc-zcoin-one-of-most-undervaluated-anonymous-coins-right-now/

[zcoinofficial]

Zcoin is happy to be listed on the Korean exchange UPBit.com launched by Kakao, Korea's biggest messaging app.

UPBit.com

[zcoinofficial]

Zcoin 0.13.3 - Mandatory Upgrade

Instructions

Make sure back up wallet.dat before updating to this version.
You can do this from the GUI by going to File>Backup Wallet.

It is recommended for a reindex when upgrading to this version.
Read this guide on how to reindex.

If you are compiling from source, note updated build instructions from readme.md. If you're from 0.8.7.9 earlier, please do a fresh git clone into a new directory.

Changelog

Mandatory upgrade with hard fork at Block 60000 (approximately 9 November 2017)
Zerocoin library security improvements through the use of secp256k1. Credits to Tim Ruffing for his amazing contributions.
Fixed error with block syncs when closing wallet and other sync errors
Zerocoin mints are now standardised at 6 confirms before being able to be spent.

Known Bugs

Minor sync issues in some rare instances.

Before doing any Zerocoin mints or spend, make sure to do File>Backup your wallet.dat and save in separate location so you can restore in the case a mint/spend does not confirm.

Download
https://github.com/zcoinofficial/zcoin/releases

[zcoinofficial]

Zcoin 0.13.3.1 - Mandatory Upgrade

Instructions
If you are stuck when upgrading to this version, make sure to go into your Zcoin data directory and delete peers.dat and banlist.dat.

Read this guideon how to reindex.

If you are compiling from source, note updated build instructions from readme.md. If you're from 0.8.7.9 earlier, please do a fresh git clone into a new directory.

Changelog
Zerocoin validation fixes past block 60,000
Mandatory upgrade with hard fork at Block 60000 (approximately 9 November 2017) an updated protocol version number
Reverted spend to 1 per block for safety

Known Bugs
Minor sync issues in some rare instances.

Before doing any Zerocoin mints or spend, make sure to do File>Backup your wallet.dat and save in separate location so you can restore in the case a mint/spend does not confirm.

Download

[zcoinofficial]

Zcoin v0.13.3.2

Instructions

If you are stuck when upgrading to this version, make sure to go into your Zcoin data directory and delete peers.dat and banlist.dat. If you are stuck on block 60032, a reindex is required.

Read this guide on how to reindex.

If you are compiling from source, note updated build instructions from readme.md. If you're from 0.8.7.9 earlier, please do a fresh git clone into a new directory.

Changelog

Fixed bad txs from entering into mempool and breaking getblocktemplate
Fixes stuck block issue
The update is mandatory for old clients before 0.13.2

Known Bugs
Before doing any Zerocoin mints or spend, make sure to do File>Backup your wallet.dat and save in separate location so you can restore in the case a mint/spend does not confirm.

Download here.

[cryptoking]

Zcoin (XZC) Released Electrum wallet version 3.3.8 - Addition 4

What's new

Fixed the issue with Trezor being unable to spend Sigma inputs
Fixed the issue with inability to sign a message with Ledger

Upgrade instructions
Please backup your wallet secret before upgrading.

Development
For github compatibility the electrum directory left under its name. Please symlink or rename it to electrum_xzc if you are changing the source code.

Binaries
The signatures can be verified with this public key.

Download: