Mina is a succinct blockchain, and as a result, consensus nodes only store the recent history of the chain before discarding it (the last k blocks, currently 290).

While prior transaction history is not required to prove the current state is valid (this is handled via a recursive zero-knowledge proof), many applications would like access to this prior transaction history. Examples include block explorers and wallets.

To solve this problem, users may optionally run an archive node that stores a summary of each block seen in a Postgres database. …


Image by joanshannon from Pixabay

Since writing this post, Coda has rebranded to Mina Protocol. I’ve left the article in its original form but all references to Coda are equivalent to Mina.

The Coda sandbox node enables creating a single-node private network that you can use to test running a Coda node in a predictable environment. The 3.3 release of the sandbox node includes the new Pickles SNARK and support for tokens.

For a step-by-step guide to completing the Coda Pickles Sandbox challenges see this guide by community member Ducca

The sandbox node contains all of the network’s funds on a single private key, and…


Since writing this post, Coda has rebranded to Mina Protocol. I’ve left the article in its original form but all references to Coda are equivalent to Mina.

Docker provides one of the simplest ways of getting a Coda node up and running while providing the benefits of container isolation. It also resolves issues around dependencies on unsupported systems and allows specifying restart policies should the daemon crash.

It is important to use the correct image for each testnet release. The tags for all releases are available on DockerHub. For testnet 3.2b this tag is 0.0.12-beta-feature-bump-genesis-timestamp-3e9b174. …


Since writing this post, Coda has rebranded to Mina Protocol. I’ve left the article in its original form but all references to Coda are equivalent to Mina.

This post provides an introduction to the current implementation of the Coda Javascript SDK. Using the SDK, it is possible with Javascript to generate keys, sign and verify messages, and sign transactions that can be broadcast to the network. From the package’s Readme:

This is a NodeJS client SDK that allows you to sign transactions and strings using Coda’s keypairs. …


Since writing this post, Coda has rebranded to Mina Protocol. I’ve left the article in its original form but all references to Coda are equivalent to Mina.

Coda is a succinct blockchain where full nodes only require downloading and verification of a tiny proof to ensure that the state of the blockchain is valid. It achieves this through incrementally computed SNARKs where the latest block contains a proof that validates the new block in addition to the previous SNARK.

For the full technical details of Coda’s consensus mechanism consult the Coda technical whitepaper.

Coda utilizes a proof of stake (PoS)…


Since writing this post, Coda has rebranded to Mina Protocol. I’ve left the article in its original form but all references to Coda are equivalent to Mina.

If you are unfamiliar with the Coda protocol or the Coda GraphQL API see my previous article for an overview.

A block explorer is a tool typically used to visualise the current and historical state of a blockchain including all transaction information.


While 2018 was largely dominated by the declining price of ZEC (and all major cryptocurrencies), it marked a significant milestone in the evolution of Zcash with both the Overwinter and Sapling network upgrades taking place. As a result, shielded transactions can now routinely be sent in a couple of seconds using a fraction of the RAM previously required (~40MB). Despite this, the percentage of shielded transactions on the network is still low, and as such, there is a greater emphasis on the adoption and usability of shielded transactions.

Sapling was activated on October 28 2018

Sapling is an enabling technology that allows for other services and tools…


Since writing this WinZEC has reached end of life and it is recommended that users switch to zec-qt-wallet due to its ongoing support and updated feature set. Simply install zec-qt-wallet and it will use the existing data directory and wallet from WinZEC.

WinZEC (formerly Zcash4Win) was the first port of the official Zcash client (known as zcashd) to Windows. As a result, it still powers a large proportion of the Zcash nodes on the network for those who wish to use shielded transactions on a Windows machine.

WinZEC is comprised of two major components, the Swing wallet GUI(the interface that…


2017 was an excellent year for Zcash as the protocol developed, matured, and the ecosystem expanded. The market-cap surpassed $1 Billion, and it is now well supported on various exchanges.

There are many repeated concerns and sources of misinformation spread about Zcash and, while the technology is still in its infancy, it is rapidly evolving to actively address these concerns. Such concerns primarily focus on the nature of the trusted setup, the performance cost of completing a shielded transaction and the fact that private transactions are not mandatory for all Zcash transactions.

In this article, I’ll outline some of the…


2017 saw a meteoric rise in the price of Bitcoin, closing the year off its all-time high but registering a gain of close to 1400%. Over $1.6 Billion traded on BTC/CAD trading pairs monitored as part of the Canadian Bitcoin Index.

Following on from 2015, and 2016 Bitcoin notched another series of records during 2017 with a new all-time high of $25,497.14 on dramatically increased exchange volume. At the close of the year, Bitcoin was trading some 30% lower than the peak at $18,331.23.

Bitcoin opened the year at $1317.33 and reached its low for the year at $1046.15 on…

Gareth Davies

Technical writer, data wrangler and (former) full stack dev

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