Reaching Everyone, Pt. II: Resilience, Censorship-Resistance and the Bitcoin Blockchain

Source: Kevin Durkin for In The Mesh

ICYMI on In The Mesh, read the next parts there first.

This article is the second in a four-part series by Matt B (@MattoshiN) and Wassim Alsindi (@parallelind) on the use of Bitcoin and the technology stack built atop it to assist those living under oppressive regimes or in conflict zones, and those seeking to flee them.

The detrimental effects of government-mandated money — and conversely, the benefits of sound money adoption — were discussed in the previous article in this series, as were the properties that make Bitcoin a powerful and permissionless alternative to fiat. In this piece, we’ll focus on the technology that makes the protocol so robust and why that matters in today’s world. It’s wise to first provide a definition for Bitcoin, not an easy task. As a complex ensemble of components giving rise to a series of emergent behaviours and phenomena, the what of Bitcoin appears to have a lot of subjective baggage attached. Bitcoin scribe Nic Carter has tackled some epistemological and ontological perspectives of Bitcoin, as informed by wider phenomenology.

The Bitcoin name refers to several things: the broadcast ‘push’ messaging protocol, the peer-to-peer network of nodes running client software and UTXOs (unspent transaction outputs) or ‘pieces of bitcoin’. The record of transactions between users’ addresses is notarised using a high-assurance data structure — the ‘blockchain’ — which is synchronised across the network’s nodes allowing a ledger to be constructed permissionlessly by anyone who runs the Bitcoin client software. The global state of the transaction history is kept in agreement. The true state of the ledger is maintained by the thermodynamic competition to create blocks (Proof-of-Work, or PoW ‘mining’), ensuring that massive expenditure of computational power and energy would be required for a prospective attacker to rewrite the blockchain and therefore alter Bitcoin’s historical record. Miners are rewarded with bitcoins for winning the race to find candidate blocks and broadcasting them to the network, provided the protocol has been followed and the network reaches agreement on the next block to be added to the chain. Transactions are included in each block, the order of which is determined by a ‘fee market’, with higher priority transactions incentivising miners to include them with above average fees.

From a user’s perspective, Bitcoin is a payment system that allows them to send payments without regard for borders, governments or geographical distance. Once a transaction has been included in a block, it is said to have a single confirmation. With each subsequent confirmation, it becomes harder for an adversary to reverse, alter or censor it. In times of normal network operation, a transaction is considered final and spendable once it has six confirmations — though in reality the finality is probabilistic rather than absolute. In other words, it is extremely unlikely to be reversed, rather than impossible. Though Bitcoin has not experienced large-scale reorganisations of its ledger history (so-called ‘majority’ or ‘51%’ attacks), it is becoming an increasingly common occurrence in smaller PoW networks. As a user, what could be less confidence-inspiring than the prospect of storing your precious value in a fragile network which gets disrupted relatively easy and often? It’s akin to leaving your front door ajar and wondering why things keep getting messed up.

The one-way SHA-256d hash function plays an integral role in the Bitcoin ecosystem (and in the wider field of public-key cryptography), leveraging the asymmetry of ‘guessing’ or ‘brute-forcing’ a private key associated with a public key versus the ease of proving that said public key is associated with the private key. Similarly, blocks are very difficult to ‘guess’ (enter the PoW algorithm), but it’s trivial to prove that one has been found.

In essence, the hash function is a deterministic process which takes a piece of information (of any length) and returns a piece of information of a specific length. Think of such a function as a meat grinder — you can put a cut of fine Kobe beef through one to produce mince, but it is all but impossible to reverse-engineer the original.

Despite ecocentric narratives around “Bitcoin boiling the oceans”, PoW is the most secure, equitable and effective mechanism for the addition of a block that exists today. It’s entirely possible to swap the algorithm for a consortium or single party creating new blocks via some other mechanism, but this would sacrifice the entire value proposition by centralising production and validation. The notion of ‘autonomous entry’ is vital to the decentralisation of Bitcoin, and, by extension, its most attractive characteristics encapsulated by resilience against external control and coercion: permissionlessness (anyone can be part of the network), censorship-resistance (anyone can transact) and immutability (transactions are final). Since its launch in January 2009, the network has enjoyed 99.983% uptime.

Decentralisation isn’t easily reduced to a binary phenomenon, more closely resembling an emergent, complex and multidimensional spectral characteristic. The notion was originally espoused by de Toqueville as an antonym to the centralisation of state power before and after the French Revolution. A number of approaches to characterise decentralisation as a meaningful or even quantifiable metric have been made, with varying insights and approaches. In a given network, you’ll probably want to consider a myriad of different factors such as the technology, the organisation (or lack thereof) of the participants, the data structures that host the historical record and the topology of the network itself. To all intents and purposes, Bitcoin fares quite well with all of these metrics — hashpower centralisation may be an issue, though game theory and “skin in the game” due to sunk costs in equipment outlay would in most circumstances incentivise an actor in possession of a significant amount to act honestly. An example of this was the mining pool which breached 50% of network hashrate in 2014, before widespread commotion and redistribution of computational resource. The exodus was so pronounced that the pool ceased to exist shortly afterwards.

Source: Kevin Durkin for In The Mesh

Let’s attempt a finer grain perspective of what these concepts embody employing this layered approach. Immutability is an attribute primarily observed at the protocol layer — upon which the monetary layer depends for persistence — ensuring the inability of stakeholders or adversaries to alter the transaction record and thereby balances. Censorship-resistance is also primarily observed at the protocol layer, as valid transactions of any type are not prevented from being broadcast to the P2P network, included in blocks and recorded in the network’s shared ledger.Permissionlessness can be regarded as a related phenomenon on the social layer, where no persons or entities are prevented from broadcasting transactions and being included in the ledger, so that anyone can participate and use the network without prejudice.

Decentralisation itself can be taken to mean different things when considering the various layers in our model. Protocol decentralisation would refer to distribution of nodes fully validating the ledger from it’s genesis and incentives for mining and validation of transactions and/or blocks. Monetary decentralisation can be assessed by studying inequality in the concentration of asset distribution, though this is an imperfect heuristic in cryptocurrencies as an entity may control many public keys, which in turn can generate many addresses. A more pressing issue is the quantity of bitcoin held by centralised exchanges — Coinbase alone custodied at least 5% of all BTC as of late 2018.

Social decentralisation pertains to the decision-making and consensus reaching methods of a network, and whether some subset of stakeholder constituents are able to exert undue degrees of explicit or implicit influence over a network’s outcomes. The “implicit user contract” of Bitcoin has been described recently as a positive feedback loop between the protocol and social layers reinforcing each other, and also as an intersubjective consensus arrived at by a distributed group of users, similar to the game theoretical notion of a focal or “Schelling” point.

With this in mind, the oft-quoted concept of ‘code is law’ which refers to immutability in cryptocurrency networks, typically referring more to preserving the intended use and function of a system and its ledger rather than a blind adherence to a software implementation regardless of flaws or vulnerabilities. For example, a recent critical vulnerability in some versions of the “reference implementation” of Bitcoin’s software client — Bitcoin Core — would have allowed an adversary to crash mining nodes on the network and clandestinely create further supply of bitcoin UTXOs, thereby violating the supply cap. There was little resistance to fixing this as it was deemed to be an obvious software bug in clear contradiction of the implicit but mutually understood ‘rules of Bitcoin’. However a similar issue became extremely contentious in the Ethereum network in 2016 following the catastrophic failure of an investment-focused smart contract suite known as “The DAO”, leading to a network split as actions taken to delete certain balances including some “child DAOs” (that were not ascribed to the attacker) was considered a violation of the network’s immutability and the promise of “unstoppable applications”. This led to the creation of a new network keeping the Ethereum name, and a continuation of the original network’s philosophy known as Ethereum Classic, where a significant minority of the original Ethereum community continued mining, developing and maintaining the network built around the canonical blockchain.

Though the above events were both related to unintended function of network software, the lack of contention with the recent Bitcoin Core vulnerability (CVE) as compared to the Ethereum network fragmentation following the exploitation of The DAO can be rationalised by examining the differences in the two sequences of events. The Bitcoin Core bug affected a wallet implementation, whereas The DAO was a suite of on-chain smart contracts holding around 15% of all ETH supply. Secondly, the Bitcoin Core CVE was responsibly disclosed and promptly patched by most miners (who were the most vulnerable to exploitation) whilst Ethereum was perceived to have handled The DAO situation poorly, despite multiple researchers publically calling for caution and further code auditing prior to launch. Finally, there was significant disagreement over the best way to proceed in light of The DAO’s failure, with a number of solutions proposed. An on-chain “carbon vote” was taken to assess the network stakeholders’ moods, though this was marred by low turnout and large votes by single blocs of whales and insiders.

Bitcoin’s key characteristics — scarcity, decentralisation, immutability, censorship-resistance and permissionlessness — are a result of careful design and development over the past decade and represent some of the most significant achievements in computer science and engineering to date. That being said, much work remains to be done in order to realise the ultimate potential of cryptocurrency as an impenetrable guerilla financial armoury empowering the dispossessed peoples of Earth against authoritarianism and oppression.

Next up at In The Mesh: two more instalments in this series and more on the potential of cryptocurrency to empower those living under authoritarianism.

Wassim Alsindi directs research at independent laboratory Parallel Industries, analysing cryptocurrency networks from data-driven and human perspectives. Find him at and @parallelind on Twitter.

Matt B is a writer and content strategist in the cryptocurrency space with a particular interest in Bitcoin and privacy technology. He can be reached at and @MattoshiN on Twitter.

Images by Kevin Durkin for In The Mesh

Reaching Everyone, Pt. I: The Need For Sound Money Outside of the Wealthiest Territories

Reaching Everyone, Pt. I: The Need For Sound Money Outside of the Wealthiest Territories

ICYMI on In The Mesh, read the next parts there first.

This article is the first in a four-part series by Matt ฿ (MattoshiN) and Wassim Alsindi (@parallelind) on the use of Bitcoin and the technology stack built atop it to assist those living under oppressive regimes or in conflict zones, and those seeking to flee them.

In developed nations, the widespread adoption of Bitcoin may not seem all that urgent to many. Indeed, it would be reasonable to say that its need at the individual level hasn’t yet widely manifested itself. While everyone’s excited about Lightning Network transactions overtaking existing fiat gateways for buying coffee or paying for bus tickets, the fact is that if some critical security flaw caused the irreversible collapse of the Bitcoin network overnight, we’d survive. Life would go on. The legacy financial infrastructure is relatively stable in many nations — at least in the short-term. Where cryptocurrency can shine brightest is in areas where economic and/or political actions of governments are failing.

Indeed interest and use of Bitcoin and cryptocurrency generally appears to be on the rise in regions where individuals are desperately in need of forms of wealth and value transfer that cannot be confiscated, debased or censored by authoritarian governments, local mafias or cartels. This has traditionally been difficult.. The state printing press is a machine that, left unchecked, can recklessly and often surreptitiously add to the existing monetary supply in such a way as to cause hyperinflation, a disaster we’ve seen unfold in the Weimar Republic in the 20s and the latter stages of the Roman Empire, and in VenezuelaIran and Zimbabwe at present. As for commodity monies, they have been subject to confiscation and dilution in the past — consider Executive Order 6102 in the US, where the government coerced citizens into turning over bullion and coins.

Aristotle defined the desirable properties of money in the fourth century BC as transportability, fungibility, scarcity and divisibility. Bitcoin largely satisfies the criteria above — analogous to the mining of precious metals, the generation of Bitcoin blocks requires significant expenditure on the part of the miner (hardware, electricity, infrastructure and running costs) to acquire a provably scarce asset with a total supply capped at 21 million coins. Arguably, this makes it rarer than gold, whose supply constraints are merely presumed, and current valuation does not account for that which simply isn’t economically feasible to extract — i.e. in Earth’s oceans or in space.

Like precious metals at present, synthesising a Bitcoin, outside of the parameters explicitly permitted by the network in the form of mining, is impossible. Any attempt at doing so would simply be incompatible with the network. Each coin can be divided into 100,000,000 units, and one UTXO (unspent transaction output) unit is functionally equivalent to another — though there are current limitations to the fungibility of Bitcoin insofar as tainting and blacklisting is concerned. (In an upcoming piece, we’ll be covering some in-protocol and extra-protocol solutions to these challenges).

Evidently, hard money existing in cyberspace would present numerous benefits over physical alternatives: concealability, plausible deniability, programmability, portability and easy global transmission. Precursors to Bitcoin such as Wei Dao’s b-money or Szabo’s bit gold made strides in the direction of solving key distributed computing problems involving the double spending of digital money, although they were imperfect as degrees of centralisation were required prior to the use of proof-of-work and chain selection rules as a mechanism to mitigate Sybil attacks and reach network consensus. Whilst there’s a push towards institutionalising Bitcoin as a marker of establishment acceptance, that was never what the cypherpunk and crypto-anarchist movements from which it originated saw as important. Both have always focused on liberating individuals by arming them with cryptographic tools and protocols to defend their sovereignty from would-be oppressors, hierarchies, rulers and dominators.

2017 report from Freedom House indicates that over half of the world’s countries are ruled by governance structures considered to limit citizen freedom. Of the 195 countries assessed, 87 (45%) were rated ‘Free’, 59 (30%) ‘Partly Free’, and 49 (25%) ‘Not Free’. A common theme that appears to prevail in countries deemed ‘not free’ is the exertion of monetary and economic domination as a key mechanism of social control. This is typically achieved by issuing weak or undesirable fiat currency, which does not retain purchasing power over time due to mismanagement of the monetary issuance policy due to incompetence or malice — or some combination of the two.

The possibility of secure digital money has unbridled potential for both those living under authoritarian regimes, as well as those seeking to escape them. While it may take decades to see Bitcoin cannibalise fiat currencies, it already has great potential as a contender to them. A monetary system operating in parallel to a state-enforced one redistributes the power from the incumbent issuer to the population, and dampens the effectiveness of the state printing press.

Next up at In The Mesh: three more instalments in this series and more on the potential of cryptocurrency to empower those living under authoritarianism.

Wassim Alsindi directs research at independent laboratory Parallel Industries, analysing cryptocurrency networks from data-driven and human perspectives. Find him at and @parallelind on Twitter.

Matt B is a writer and content strategist in the cryptocurrency space with a particular interest in Bitcoin and privacy technology. He can be reached at and @MattoshiN on Twitter.

Images by Kevin Durkin for In The Mesh

20/12/18 “The Secret Lives of Cryptocurrencies” talk at Genesis Block Hong Kong



Wassim will be delivering a new talk entitled “The Secret Lives of Cryptocurrencies” at Genesis Block Hong Kong on Thursday 20th December. Do register your attendance if you’re coming at the link below.

Forkonomy and Reaching Everyone head to the Ethereum Classic Summit in Seoul Sep 2018


Wassim speaks at the Ethereum Classic Summit in Seoul, Korea on September 12-13.

In addition to a presentation on implications of Forkonomy for ETC, Wassim will also participate in a panel discussion on the topic of censorship resistance and immutability as informed by Reaching Everyone.

More information can be found on the ETC Summit website. Though tickets are no longer available, the event will be livestreamed on YouTube.

Slides –

Talk –

Censorship-Resistance & Immutability Panel with Anthony Lusardi, Alison Alexis, Kong Gao, Virgil Griffith



Project Update: Reaching Everyone

Next actions: More script & tool PoCs, UX/UI and HW research.

Reaching Everyone Article Series (co-authors Matt B & Wassim Alsindi)

Part 1: The Need for Sound Money Outside the Wealthiest Territories. Read at In The Mesh / Hacker Noon

Part 2: Resilience, Censorship-resistance and the Bitcoin Blockchain. Read at In The Mesh / Hacker Noon

Part 3: soon!

Part 4: soon

Slides from Chainhack, Lisbon: