Rbitcoin Package

# cited from: https://www.r-bloggers.com/querying-the-bitcoin-blockchain-with-r/
# install.packages("Rbitcoin")
library(Rbitcoin)

1. 以Public API下載匯率

Bitcoin屬於permissionless的blockchain，任何人都可以使用Public API下載匯率資料：

wait <- antiddos(market = 'kraken', antispam_interval = 5, verbose = 1)
market.api.process('kraken',c('BTC','EUR'),'ticker')

##    market base quote           timestamp market_timestamp last     vwap
## 1: kraken  BTC   EUR 2017-11-18 21:30:06             <NA> 6570 6579.426
##      volume  ask    bid
## 1: 6089.515 6570 6562.8

trades <- market.api.process('kraken',c('BTC','EUR'),'trades')
Rbitcoin.plot(trades, col='blue')

2. 以Private API操作錢包(交易)

要使用bitcoin做交易，就要先建立自己的帳號，然後才可以使用錢包做交易：

wallet <- blockchain.api.process('15Mb2QcgF3XDMeVn6M7oCG6CQLw4mkedDi')
seed <- '1NfRMkhm5vjizzqkp2Qb28N7geRQCa4XqC'
genesis <- '1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa'
singleaddress <- blockchain.api.query(method = 'Single Address', 
                                      bitcoin_address = seed, limit=100)
txs <- singleaddress$txs

3. 追蹤交易對象

bitcoin的好處之一，是容易追蹤交易記錄。我們可以下載帳戶的記錄 …

bc <- data.frame()
for (t in txs) {
  hash <- t$hash
  for (inputs in t$inputs) {
    from <- inputs$prev_out$addr
    for (out in t$out) {
      to <- out$addr
      va <- out$value
      bc <- rbind(bc, data.frame(from=from,to=to,value=va, stringsAsFactors=F))
    }}}

交易記錄經過整理，就可以畫出與其(有過交易的)往來帳戶的網路圖：

library(plyr)
btc <- ddply(bc, c("from", "to"), summarize, value=sum(value))

library(igraph)

## 
## Attaching package: 'igraph'

## The following objects are masked from 'package:stats':
## 
##     decompose, spectrum

## The following object is masked from 'package:base':
## 
##     union

btc.net <- graph.data.frame(btc, directed=T)
V(btc.net)$color <- "blue"
V(btc.net)$color[unlist(V(btc.net)$name) == seed] <- "red"
nodes <- unlist(V(btc.net)$name)
E(btc.net)$width <- log(E(btc.net)$value)/10
plot.igraph(btc.net, vertex.size=5, edge.arrow.size=0.1, 
            vertex.label=NA, 
            main=paste("BTC transaction network for\n", seed))