Adam Back claims to have warned the first developers of Ethereum against an architecture that he considered faulty. However, there is no easily verifiable public evidence to establish that he had sent them, before the launch of the network, a precise warning about the account model now criticized.
In brief
- Adam Back claims to have warned early Ethereum developers of weaknesses in its architecture, without providing public proof.
- Bitcoin’s UTXO model and Ethereum’s system of accounts each have advantages and limitations.
- Concerns about the security of cryptographic signatures affect both Bitcoin and Ethereum.
- Despite his long-standing criticisms, Adam Back has not demonstrated that he alerted the founders of Ethereum before its launch.
Adam Back attacks the founding choices of Ethereum
The CEO of Blockstream reignited the debate between Bitcoin and Ethereum in a message published on October 10. He defends the UTXO model chosen by Satoshi Nakamoto and directly criticizes the experience of the first designers of Ethereum.
“It’s almost as if Satoshi knows about distributed systems”has writing Adam Back. He then claims that the developers of Ethereum were “young, naive” and lacking the necessary experience when they built the network around an architecture that it considers to be “obviously defective”.
His message ends with an important statement: “I tried to warn them”. Back, however, provides neither a link, nor a date, nor a copy of an exchange allowing this warning to be identified.
Public records show he has been a critic of Ethereum for several years. In 2019, he already compared the project to Theranos. In August 2020, he placed Ethereum alongside Bitconnect, OneCoin and other controversial projects, before denouncing the pre-sale of part of ETH.
These positions confirm its long-standing opposition to Ethereum. However, they do not prove that it had warned its founders, before the launch of the blockchain in July 2015, of the precise problems that it associates today with its architecture.
UTXO and accounts meet two different designs
Bitcoin uses the UTXO model, to “unspent transaction outputs”. Its operation can be compared to that of banknotes: a transaction consumes existing units and creates new outputs, which their owner can spend later.
Ethereum relies on accounts whose balance and state change with each transaction. This structure makes smart contracts easier to execute because applications can maintain and modify information directly on the blockchain.
The UTXO model makes it easier to process certain independent transactions in parallel. It also limits the amount of state shared between users and applications. The accounts system, for its part, offers more flexibility for building financial protocols and complex applications.
Present one as objectively correct and the other as necessarily ” broken “ is therefore a matter of technical and political judgment. Ethereum has been operating for over eleven years and secures hundreds of billions of dollars in assets, although its architecture brings challenges related to state growth, concurrent transactions, and contract complexity.
The network’s developers are also studying mechanisms that take advantage of certain advantages of UTXOs. EIP-8141 would notably propose a new transaction format in order to improve the abstraction of accounts and prepare for the adoption of more resistant signature systems.
The cryptographic threat also concerns Bitcoin
Adam Back’s release responds to the warning issued by Ethereum Foundation researcher Justin Drake. He believes that advances in artificial intelligence could accelerate the discovery of methods capable of weakening the cryptography of elliptic curves.
In its most pessimistic scenario, an attack could become feasible “in a few months, not a few years”. Drake therefore recommends gradually preparing to transfer funds to addresses whose public key has never been exposed.
However, no practical attack of this type has been demonstrated. Yehuda Lindell, head of cryptography at Coinbase, notably estimated that there is currently no evidence of a weakening of the mathematical assumptions that protect these signatures.
Above all, the choice between UTXO and accounts does not alone resolve this threat. Both Bitcoin and Ethereum use the ECDSA algorithm to authorize certain transactions. If a method really made it possible to find a private key from an exposed public key, both networks would be affected.
The UTXO model nevertheless brings a practical advantage to Bitcoin: best practices encourage the creation of a new address after each payment, which can reduce the exposure of public keys. This advantage disappears when users reuse their addresses.
An old criticism, but an unproven warning
Adam Back has real legitimacy in the history of cryptography. His Hashcash system, introduced in 1997, inspired Bitcoin’s proof-of-work mechanism. Satoshi Nakamoto also cited it in the network’s white paper.
This expertise, however, is not enough to retrospectively confirm his assertion. In the absence of dated archives, it remains impossible to establish to whom Back would have sent his warning, at what time and about what precise risk.
The most rigorous conclusion therefore remains nuanced: Adam Back has been criticizing Ethereum for a long time, but his assertion that he warned its creators against their account model remains unsupported publicly.
Maximize your Tremplin.io experience with our ‘Read to Earn’ program! For every article you read, earn points and access exclusive rewards. Sign up now and start earning benefits.
