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Why Understanding P2PKH is Important in Blockchain

January 13, 2017
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Introduction P2PKH is an important acronym to learn. It stands for “Pay To Public Key Hash” and is the most common form of transaction on the bitcoin blockchain. Part 1: What on Earth does “Pay to Public Key Hash” mean? In a bitcoin transaction, the “Public Key Hash” is synonymous to a “bitcoin address”. (A bitcoin address is derived from a the hash of your public key for the technically minded). So let’s reword P2PKH to mean “Pay to this bitcoin address”. That’s not so scary is it? P2PKH is therefore an instruction on the blockchain to transfer ownership from the current owner to the new owner of the bitcoin address. Why this is important to understand? This instruction can be modified for example to say, “pay to this bitcoin address OR that bitcoin address”. This is basically a smart contract in its simplest form. It is also known as multi-sig. A multiple signature condition that states “please provide any 1 of the 2 provided bitcoin addresses for this transaction to evaluate to true and execute”. That is the basics of P2PKH. Part 2 tackles this from a technical angle. Part 2: What does it “technically” really mean? There are […]
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Good overview of some technical blockchain concepts

January 12, 2017
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This is a good resource for some really technical information on bitcoin and blockchain fundamentals. You know you’re getting heavy when you see the word endian! The information was well laid out over several  sections and the concepts built upon each subsequent section. The audience expectations were laid out which was a nice touch. I would have included the section number in the title so I knew how far in I was and how many more sections there were. The term “outpoint” was introduced in section 9 and I first thought it was a typo for output but Davide confirmed it wasn’t. It would have be good if it was explained in a bit more detail. The example code was one of the highlights. A lot of people talk about stuff, but it’s the implementation or the “how” part that is the hardest. The last section on wallets was interesting as well. This would be a good area to possibly expand on.  
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OpenSSL Cookbook

January 11, 2017
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Blockchain technology relies heavily on understanding public and private keys. How they are generated and used. This OpenSSL Cookbook is a good reference. I found the first half more informative and useful than the second half. Here is the link to the online version: https://www.feistyduck.com/library/openssl%2dcookbook/online/ For other formats, check out: https://www.feistyduck.com/library/openssl-cookbook/
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Learning The Lightning Networks

January 10, 2017
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There are lots of resources to read when learning about the Lightning Network for blockchain transactions. Here is a recommended list of resources in a specific order. Lightning Network Summary from https://lightning.network is a great one pager that is very clearly written and provides a great summary intro. https://www.youtube.com/watch?v=8zVzw912wPo “The Scaling Bitcoin to Billions of Transactions Per Day” also on the lightning.network home page is important as well. It is clear with good examples. This 3 part article does a good job also. https://bitcoinmagazine.com/articles/understanding-the-lightning-network-part-building-a-bidirectional-payment-channel-1464710791 https://bitcoinmagazine.com/articles/understanding-the-lightning-network-part-creating-the-network-1465326903 https://bitcoinmagazine.com/articles/understanding-the-lightning-network-part-completing-the-puzzle-and-closing-the-channel-1466178980 Finally, some discussions at bitcoin.stackexchange will come from a different angle also. http://bitcoin.stackexchange.com/questions/43700/how-does-the-lightning-network-work-in-simple-terms http://bitcoin.stackexchange.com/questions/42639/what-are-the-trade-offs-between-transacting-on-lightning-network-and-bitcoin-mai These are your starters. If you want to get more technical, the whitepaper from the https://lightning.network homepage is your next step. It’s 59 pages and the first 10 or so pages are ok, but it then jumps another gear. Unfortunately what put me off was the abstract. The bitcoin protocol can encompass the global financial transaction volume in all electronic payment systems today, without a single custodial third party holding funds or requiring participants to have anything more than a computer using a broadband connection. A decentralized system is proposed whereby transactions are sent over a network of micropayment channels (a.k.a. payment channels or […]
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Banking on Bitcoin

January 9, 2017
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A neat documentary showing some key players in the industries history. It doesn’t fully cover all the aspects but if it did, it would probably be double the current length of 90 mins. It shows some useful insights and if you have read some of the books including Digital Gold and The Age of Cryptocurrency the various authors help to provide their view and part narration also.         What was interesting was I had just finished the “Bitcoin and Cryptocurrency Technologies” course by Princeton University and saw one of the lecturers Ed Felton there also  
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A very high quality Bitcoin Blockchain Online Course

December 31, 2016
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Introduction If you are serious about cryptocurrencies and blockchain technologies, this is the course you want to take. To borrow a line out of “The Chase UK”, it’s a course “right out of the top drawer“. Don’t let the course title “Bitcoin and Cryptocurrency Technologies” mislead you. It’s all about “blockchain” technologies. With the “blockchain” rave rampant, this course highlights blockchain technologies specifically with bitcoins as the example application. Content I missed the first intake for this course about a year ago but managed to enrol this time around. It’s presented as an 11 week course and with lectures via videos. Summary of course. See full details here: Week 1: 6 videos, 55 min: Introduction to Crypto and Cryptocurrencies Week 2: 5 videos, 71 min: How Bitcoin Achieves Decentralization Week 3: 6 videos, 74 min: Mechanics of Bitcoin Week 4: 7 videos, 78 min: How to Store and Use Bitcoins Week 5: 5 videos, : 84 min: Bitcoin Mining Week 6: 6 videos, 109 min: Bitcoin and Anonymity Week 7: 8 videos, 69 min: Community, Politics, and Regulation Week 8: 5 videos, 42 min: Alternative Mining Puzzles Week 9: 5 videos, 83 min: Bitcoin as a Platform Week 10: 4 videos, 62 min: Altcoins and the Cryptocurrency Ecosystem Week 11: 4 videos, 82 min: The […]
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OP_RETURN 40 to 80 bytes

December 30, 2016
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At first it is really confusing understanding the actual size of the OP_RETURN field. This field in a bitcoin transaction allows arbitrary data to be written to the bitcoin blockchain and was “standardised” in v0.9.0 of the bitcoin core client on 19 March 2014. The core developers noted however that “Storing arbitrary data in the blockchain is still a bad idea; it is less costly and far more efficient to store non-currency data elsewhere. 5 Jun 2013 was the initial pull request for the 80 byte OP_RETURN https://github.com/bitcoin/bitcoin/pull/2738 These notes go with it: http://bitcoinfoundation.org/core-development-update-5/ On 25 Feb 2014, it was proposed to be reduced to 40 bytes as can be seen by this pull request https://github.com/bitcoin/bitcoin/pull/3737. The comments make an interesting read! It was then accepted (merged) into the code on 27 Feb 2014 as part of v0.9.0. On 16 Nov 2014 there was a pull request to have the OP_RETURN size increased “back” to 80 bytes. https://github.com/bitcoin/bitcoin/pull/5286 “The maximum size for OP_RETURN outputs used to be 80 bytes, then got changed to 40 bytes to be on the safe side. We have now been running with 40 bytes for about 9 months, and nothing catastrophic happened to the Blockchain, so I am proposing to increase […]
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Ethereum Mist flag provided but not defined

December 26, 2016
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I downloaded Mist-win64-0-8-7.exe and had Mist 0.8.7 running on Windows 64 bit 8.1. Then a few days later I tried opening it and got this message: Couldn’t connect to node? See the logs for more: Node type: geth Network: main Platform: win32 (Architecture x64) … flag provided but not defined: -support-dao-fork I was at a loss. Googling actually didn’t turn up anything useful at all which was even more surprising. The way I eventually resolved this was to download the latest version (0.8.8) which loaded up correctly and re-sync. No funds were lost things are back to normal again!
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Segregated Witness Explained Like I’m 5

December 21, 2016
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Introduction Segregate Witness is a neat concept invented by Pieter Wuille. Pieter has a Ph.D in computer science and is part of the bitcoin core development team since 2011. What is SegWit? The short non technical version Segregated Witness, or SegWit as it is commonly known is where data, or more specifically data related to signatures are removed from bitcoin transactions making them smaller in size. This in turn makes the blocks smaller meaning more transactions can be included in a block. The short technical version “Segregated witness (segwit) is a soft fork that, if activated, will allow transaction-producing software to separate (segregate) transaction signatures (witnesses) from the part of the data in a transaction that is covered by the txid.” The long version Background SegWit was officially released on October 2016 in v0.13.1 of the bitcoin core code. It’s the result of about 1 years work and was presented at the Bitcoin Scaling Conference in Hong Kong in December 6th 2015. The details To fully understand SegWit, it is important to understand the make up of a block and a transaction. Inside a transaction are scriptSig and scriptPubKey fields. This is where signature data is contained. Pieter asks the […]
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Ethereum reference links

December 18, 2016
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Here is a neat site with lots of Ethereum related links: http://cryptocentral.info/topic/11/ethereum-eth-pow-pos-ethash Replicated here in case that link breaks. Website: https://www.ethereum.org/ http://wiki.ethdev.com Documentation: https://www.cryptocompare.com/mining/guides/how-to… https://github.com/ethereum/go-ethereum/wiki/Minin… https://ethereum.gitbooks.io/frontier-guide/conten… https://github.com/ethereum/wiki/wiki https://blog.ethereum.org Stats: https://stats.ethdev.com/ https://eth-status.org/ Forums: https://forum.ethereum.org/ https://www.reddit.com/r/ethereum Developers: http://ethdev.com/ Wallets: https://github.com/ethereum/mist/releases/download… Online wallet: https://ethereumwallet.com/ The following full-node implementations of Ethereum are available: Geth, written in Go Eth, written in C++ Ethereum J, written in Java pyethapp, written in Python ethereumjs, written in JavaScript ethereumH, written in Haskell Ethereum Blockchain As a Service On Azure: https://azure.microsoft.com/en-in/blog/ethereum-bl… Block Explorer: https://live.ether.camp/ https://etherscan.io/ https://www.etherchain.org/ http://ether.fund/explorer https://explorer.etherapps.info/ https://tradeblock.com/ethereum/ https://github.com/etherparty/explorer (Git Source) https://ethereumblocks.info/ Exchanges: https://poloniex.com/exchange/btc_eth https://www.gatecoin.com/public/markets https://www.kraken.com/ https://www.cryptsy.com/markets/view/ETH_BTC https://bittrex.com/Market/Index?MarketName=BTC-ET… https://hitbtc.com/ https://bleutrade.com/exchange/ETH/BTC https://coinsquare.io/ https://metaexchange.info/markets/ETH/BTC https://alcurex.org/index.php/crypto/index https://yunbi.com/markets/ethcny https://www.cryptocompare.com/coins/eth/markets/BT… Tools: http://ether.fund/tool/contract http://ether.fund/tool/etherface http://ether.fund/tool/terminal http://ether.fund/peers http://ether.fund/tool/converter http://ether.fund/tool/calculator http://ether.fund/tool/gas-fees http://ether.fund/tool/gas-price http://ether.fund/tool/blockcast Contracts: http://ether.fund/contracts/ Cloud Mining: http://www.ethercloud.info/ Mining Pools: http://ethereumpool.co/ http://eth.nanopool.org/ https://eth.suprnova.cc/ http://ethpool.org/ https://eurohash.net/#/ http://www.talkether.org/ https://www2.coinmine.pl/eth/index.php?page=statistics&action=blocks https://eth.pp.ua/stats/ Social: https://twitter.com/ethereumproject https://plus.google.com/+EthereumOrgOfficial https://www.facebook.com/ethereumproject/ IRC Chat: bitly.com/irc_ethereum #ethereum: for general discussion #ethereum-dev: for development specific questions and discussions ##ethereum: for offtopic and banter #ethereum-mining: for mining only conversations #ethereum-markets: for discussions about markets
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That’s a wrap for Blockchain Wellington 2016

December 15, 2016
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2016 has been the year of the great rekindle of the bitcoin and blockchain community in Wellington. The year started off on February 10th at the Brewery Bar lead by Dave Moskovitz. It then went quiet for a while and was kicked back into life with a meet up in September hosted by API Talent. We’ve been building momentum ever since thanks to 3 Months and Bizdojo/Collider and ended last evening with a talk on Ethereum mining, a demo of an Ethereum app and an update from Mark from 3 months on some of the exciting events in the pipeline for 2017, so stay tuned. Last night Felix gave a great Ethereum demo called EthBay where he sold a laptop and showed how it worked under the covers. IPFS is also an exciting technology that Felix covered also. I shared my experience on how I built an Ethereum miner to learn about blockchains and made a whopping negative $0.20 per day in the process. As mentioned, we’ve got some exciting things planned for 2017 so stay tuned!
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When was Mist introduced?

December 14, 2016
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Mist was introduced on July 9th 2016. It was labelled not as version 1.0 or 0.1 but as 0.8. This is because it continued using the version number of the Ethereum Wallet. https://github.com/ethereum/mist/releases/tag/0.8.0 links to the release and also explains the thinking behind the Mist/browser concept. You can think of Mist as the browser for decentralized apps. Like what Firefox or Google Chrome are for the Web 2.0, the Mist Browser will be for the Web 3.0. What is interesting is that in November 17 2015 in v0.3.6 there was a secret open source release of Mist (https://github.com/ethereum/mist/releases/tag/0.3.6) that essentially served as an early access programme.
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Introduction to Bitcoin by Andreas Antonopoulos

December 12, 2016
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Presented at the Singularity University’s Innovation Partnership Program, this talk by Andreas is an entry level talk about bitcoin. It’s 24 minutes long and is a great watch. Lots of analogies and parallels drawn. Worth a watch.    
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Another fantastic and passionate talk by Andreas Antonopoulos

December 7, 2016
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  Andreas Antonopoulos – Currency Wars and Bitcoin Neutrality. This is worth an hour of your time. Some highlights: 4:30: India withdraw 500 and 1000 rupee notes. 28:00: End of talk. Q&A 34:25: Memorise 12 word seeds and just walk across the border + setting up a bitcoin wallet is not that hard compared to what people in Venezuela have to go through. 54:00: How much should you invest in bitcoins? 57:30: Will bitcoin be banned in China?    
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Next Wellington Blockchain Meetup: 15th December 2016

December 5, 2016
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The next Wellington Blockchain meet up will be on 15th December at 5:30pm at Bizdojo. The last one of the year! On the agenda… How to build an Ethereum miner and how it helps in learning blockchains technologies. Distributed Applications (Dapps) development in Ethereum. The latest developments at www.blockchainlabs.nz Come on down and join us in learning about this disruptive technology that is going to be big! Blockchain Mining & Dapp Development Thursday, Dec 15, 2016, 5:30 PM Bizdojo115 Tory Street Wellington, NZ 25 Members Went Hello fellow Blockchain Enthusiasts! We will be having another meetup on the 15th of December.  We will be discussing a few topics including:Learning blockchains via miningSean shares his experience on setting up an Ethereum miner, how it works, and how it helps in learning the fundamentals of Ethereum and Blockchain in general.Here’s some b… Check out this Meetup →
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Wellington Blockchain November Meet Up Summary

November 10, 2016
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It was another good meet up in Wellington yesterday evening with a few more new faces which was great to see. The evening started with a presentation from myself on “Blockchain Consensus with Proof of Stake” and then with Brett Holland from Creative HQ talking about the KiwiBank Fintech Accelerator The most interesting part was perhaps the questions at the end of each presentation where the audience members could get involved and share their experiences and insight. I talked about what proof of stake is, how it works and it’s relation to Ethereum. Here is a link to the slide deck here. Checkout the video below. Brett gave an insight into the KiwiBank Fintech programme and how it works. Mark posed an interesting question on the oxymoron of blockchain technology disrupting the financial industry but then having KiwiBank as one of the main sponsors. We are looking for speakers for a 5-10 minute slot so if you have something you want to share, please contact the organisers of the meet up. The next meet up will be in December with dates published soon.
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Blockchain Revolution: Don Tapscott & Alex Tapscott

November 4, 2016
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A very futuristic book with some really futuristic concepts. Great research and collection of stories and insights from many in the industry. Having been in this industry for just under 3 years I’m familiar with many of the concepts but when I talk about these concepts with those around me, I always get a blank stare. With my background in electrical engineering, software, hardware, electrical wiring skills, previous experience in working at an energy metering company and an interest in renewable energy, and combining this with blockchain technologies and micro payments, I thought about selling excess solar energy to my neighbour via the blockchain. What a cool and unique idea I thought! Then I read this book and the concept was already outlined there. Oh well. On a positive note, it at least validates it as a distinct possibility. The only thing to note about the book is that although all the ideas and concepts are amazing, it’s going to take time because this stuff is not easy. My selling excess energy to my neighbour idea is probably a 12 month project just for a small proof of concept. All going well, commercial reality is probably 5 years away. All in all […]
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POS: Prove Your Steak on the Blockchain

October 28, 2016
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Introduction The first thing that came to mind when I saw “PoS” was Point of Sale. EFTPOS is very popular in New Zealand and Australia but this has nothing to do with collecting payment. It also has nothing to do with proving how much steak you can eat. That would be interesting though! PoS stands for Proof of Stake and is one way to achieve consensus on the blockchain. Other ways to achieve consensus on the blockchain include (but not limited to): Proof of Work Proof of Activity Proof of Capacity Proof of Storage Proof of Work (PoW) is currently the most common and is being used on the bitcoin blockchain. To understand more about PoW read this. Proof of Stake (PoS) has made some noise in recent times in particular with Ethereum looking at moving away from PoW to PoS. Before we look at PoS, first let’s see why we need it. Consensus In a distributed, trustless computing network, there needs to be a way for a collection of machines to come to an agreement of facts. In a blockchain, any participating node on the network can create a candidate block very easily by obtaining the relevant software and verifying the transactions […]
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Next Wellington Blockchain meet up announced

October 24, 2016
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The next Wellington Blockchain meet up will be on 9th November at 5:30pm at Bizdojo. This is the first meet up after the merge between the Wellington Bitcoin and Ethereum NZ meet up. If you are curious and what to learn more, have questions that you want answered or want to meet with others in this industry then come along. Everyone is welcome.     We have 2 presentations: Proof of Work v Proof of Stake. Understanding the 2 consensus algorithms in the blockchain Overview of Kiwi Fintech Accelerator There will also be time to meet other enthusiast who have similar interests around bitcoins, blockchains and smart contracts. If you are doing something interesting with bitcoins, blockchains or smart contracts, give us a shout. We’d love for you to share it with the community as well. Blockchain Meetup Wednesday, Nov 9, 2016, 5:30 PM Location details are available to members only. 43 Members Went Hey guys,Let’s get together to chat about bitcoins, blockchains and smart contracts. It doesn’t matter what your background is. If you are curious and what to learn more, have questions that you want answered or want to meet with others in this industry then come along. All […]
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Sydney Bitcoin ATM Machine

October 21, 2016
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On my recent trip to Sydney, I went back to visit the only bitcoin ATM machine that allows you to withdraw cash. Unfortunately it has been removed. I was there in August 2015 and documented the interesting process. Bitcoin ATM machines are not that scary I’ve contacted Patrick from Abatech but with no success. They have recently updated their website (http://abatech.com.au) promoting their mobile wallet instead of their ATM machines. They did have 1 in Melbourne and Brisbane but who knows if they are operational as well. It was the right step in the right direction but maybe it wasn’t making as much money for the owners. It is probably ahead of its time as well.
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