- 출처 1: Arthur Brock, "Beyond Blockchain: Simple Scalable Cryptocurrencies", Holochain's Medium Blog, 2016년 4월 1일.
- 출처 2: Arthur Brock & Eric Harris-Braun, "Mutual Credit Cryptocurrencies: Beyond Blockchain Bottlenecks", http://ceptr.org/whitepapers/ , 날짜 미명기.
위 두 출처는 동일한 내용의 자료인데, (1)이 블로그에 먼저 게시되었고, 좀 더 나중에 (2)가 백서의 형식으로 완성된 것으로 보인다. 이 지은이들과 그들이 설립한 MetaCurrency Project는 통화(currency) 설계 분야에서 오랜 경험을 쌓은 전문가들이다. 아래 인용 구절 중에서 통화 하나를 설계하는 데 끼어드는 의사결정 요소가 수백 가지라면서 이 그림을 제시한다.
이하 위 [출처 2] 중 소절 제목, "Currency Design Principle: Mutual Credit"에서 첫 4문단을 원문 그대로 인용한다.
The means to design better, more equitable currencies has come a long way in the past 500 years. So, it is probably a good idea to integrate best practices from community currencies instead of just basing the design on patterns of money issuance inherited from medieval goldsmiths.
Most people think that money is just money, but there are literally hundreds of decisions you can make in designing a currency to target particular needs, niches, communities or patterns of flow. Some seemingly small decisions end up having large effects when iterated over centuries and billions of transactions. But, for the moment, let’s just stick to one core design principle regarding how units in a currency are issued.
Blockchain cryptocurrencies are fiat currencies. They create tokens or coins from nothing. Bitcoin does this through mining, allowing the miner who completes a complex processing task first, to commit the next block of transactions to the chain along with a transaction that creates a bunch of new coins. These coins are just “spoken into being” (the meaning of “fiat” in Latin) by the node committing the new block. Thus begins the challenging task of tracking all the coins that exist to ensure there is no counterfeiting or double-spending. You wouldn’t need to manage consensus about whether a cryptocoin is spent, if your system created accounts which have normal balances based on summing their transactions. Sounds simple, right?
There’s a name for this completely peer-to-peer approach to issuing managing a currency supply: mutual credit. In a mutual credit system, units of currency are issued when a participant extends credit to another user in a standard spending transaction. Picture a new mutual credit currency with all accounts having a zero balance. The first transaction could look like this: Alice pays Bob 20 credits for a haircut. Alice’s account now has -20, and Bob’s has +20.
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그리고, 같은 지은이는 다른 칼럼(대부분을 한국어로 옮긴 발췌 번역본)의 말미에서 다음과 같이 지적한다.
"통화 설계 분야에서 이루어진 진척 사항들에 대해서는 배우지 않는 것이 crypto-geeks(? 암호화폐 괴짜들)의 전형적인 특징이다. 그래서 국별 통화의 고장난 설계 내용을 암호통화 버전으로 똑같이 만들어낸다."