Develop Ethereum Cold Wallet Using Golang

Generate Ethereum HD wallet & offline sign && broadcast signed tx to network. Solution for eth cold wallet.

Install

Environment Require

Golang
Ethereum Private chain
dep
cgo or xgo (for go-ethereum dependency)
MySQL (construct tx)

go get -u github.com/wenweih/eth-cold-wallet
cd $GOPATH/src/github.com/wenweih/eth-cold-wallet
dep ensure -v -update

because of the codebase import go-ethereum, which is dependent on c, so cross compile need cgo. I hightly recommend a tool name xgo for Go CGO cross compiler, which is based on the concept of lightweight Linux containers.

go get github.com/karalabe/xgo

Next step is compile binary package for specify platform server, like this:

# for ubuner server
xgo --targets=linux/amd64 ./

if you are insterested in xgo usage, pls read the docutment: xgo#usage

Usage

Firstly, modify configure and put it in ~/eth-cold-wallet.yml

./eth-cold-wallet -h
time="2018-08-12T23:47:55+08:00" level=warning Note="all operate is recorded" Time:="Sun Aug 12 23:47:55 2018"
Generate Ethereum account and sign tx

Usage:
  ethereum-service [command]

Available Commands:
  construct   construct transactio
  genaccount  Generate ethereum account
  help        Help about any command
  send        broadcast signex transaction to ethereum network
  sign        sigin transactio
  sub         subscribe new block event

Flags:
  -h, --help   help for ethereum-service

Use "ethereum-service [command] --help" for more information about a command.

Generate HD Wallet

./eth-cold-wallet genaccount -n 3
time="2018-08-13T15:40:10+08:00" level=warning Note="all operate is recorded" Time:="Mon Aug 13 15:40:10 2018"
time="2018-08-13T15:40:11+08:00" level=info Generate Ethereum account=0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce Time:="Mon Aug 13 15:40:11 2018"
time="2018-08-13T15:40:12+08:00" level=info Generate Ethereum account=0x8Dc63ce8b979627C11f5EEf673990814D4815613 Time:="Mon Aug 13 15:40:12 2018"
time="2018-08-13T15:40:13+08:00" level=info Generate Ethereum account=0x48031a8E6150B6ED53F0342451D269f109934729 Time:="Mon Aug 13 15:40:13 2018"
time="2018-08-13T15:40:13+08:00" level=warning Time:="Mon Aug 13 15:40:13 2018" export address to file=/Users/hww/account/eth_address.csv

All elements about wallet are generated in ~/account folder:

▶ tree account
account
├── eth_address.csv
├── keystore
│   └── version_1_2018-08-13_15-40-10
│       ├── 0x48031a8E6150B6ED53F0342451D269f109934729.json
│       ├── 0x8Dc63ce8b979627C11f5EEf673990814D4815613.json
│       └── 0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce.json
├── mnemonic_qrcode
│   └── version_1_2018-08-13_15-40-10
│       ├── 0x48031a8E6150B6ED53F0342451D269f109934729
│       │   ├── 0x48031a8E6150B6ED53F0342451D269f109934729_aesdecrypt_key_marked.png
│       │   └── 0x48031a8E6150B6ED53F0342451D269f109934729_aesdecrypt_mnemonic_marked.png
│       ├── 0x8Dc63ce8b979627C11f5EEf673990814D4815613
│       │   ├── 0x8Dc63ce8b979627C11f5EEf673990814D4815613_aesdecrypt_key_marked.png
│       │   └── 0x8Dc63ce8b979627C11f5EEf673990814D4815613_aesdecrypt_mnemonic_marked.png
│       └── 0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce
│           ├── 0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce_aesdecrypt_key_marked.png
│           └── 0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce_aesdecrypt_mnemonic_marked.png
├── random_pwd_first
│   └── version_1_2018-08-13_15-40-10
│       └── randompwd.json
└── random_pwd_second
    └── version_1_2018-08-13_15-40-10
        └── randompwd.json

construct transacion

we have generated some wallets, next step is send amount of eth to the address. By conveniently, we sent ETH using Private Ethereum in our laptop.
Ethereum 私有链和 web3.js 使用

# deposit 30 ETH to test address
Welcome to the Geth JavaScript console!

instance: Geth/v1.8.10-unstable-7677ec1f/darwin-amd64/go1.9.2
coinbase: 0x37764d6eae4fad0c69cb7194896e0af7cf260885
at block: 570 (Wed, 08 Aug 2018 18:22:01 CST)
 datadir: /Users/hww/geth_private_data
 modules: admin:1.0 debug:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0

>
> eth.sendTransaction({from: eth.coinbase, to: "0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce",value:web3.toWei(30,"ether")})
"0xc8167e6ad819c6fa9dbbb8f45cf0da3c00213553af8bbfcf89bdb631e60d48da"
> web3.fromWei(web3.eth.getBalance("0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce"),"ether")
30

soft link to eth_address.csv and construct transacion for address 0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce

ln /Users/hww/account/eth_address.csv ~/

▶ eth-cold-wallet construct -n geth
time="2018-08-13T15:45:46+08:00" level=warning Note="all operate is recorded" Time:="Mon Aug 13 15:45:46 2018"
time="2018-08-13T15:45:46+08:00" level=info Time:="Mon Aug 13 15:45:46 2018" Using Configure file=/Users/hww/eth-cold-wallet.yml
time="2018-08-13T15:45:46+08:00" level=info msg="csv2db done"
time="2018-08-13T15:45:46+08:00" level=info msg="Exported HexTx to /Users/hww/tx/unsign/unsign_from.0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce.json"
time="2018-08-13T15:45:46+08:00" level=warning msg="Ignore: 0x8Dc63ce8b979627C11f5EEf673990814D4815613 balance not great than the configure amount"
time="2018-08-13T15:45:46+08:00" level=warning msg="Ignore: 0x48031a8E6150B6ED53F0342451D269f109934729 balance not great than the configure amount"

as you can see, the contructed transaction is export to /Users/hww/tx/unsign/ folder, we can copy these unsign transaction to offline computer, which is holder our wallet keys, in this example, we handle it in my laptop too.

Sign raw transaction

▶ eth-cold-wallet sign
time="2018-08-13T15:59:03+08:00" level=warning Note="all operate is recorded" Time:="Mon Aug 13 15:59:03 2018"
time="2018-08-13T15:59:03+08:00" level=info Time:="Mon Aug 13 15:59:03 2018" Using Configure file=/Users/hww/eth-cold-wallet.yml
time="2018-08-13T15:59:03+08:00" level=info msg="签名交易： 0x3f00ff54245328604a6f43f4de279de100d4afc8d5e7536eeaee7b531c2d64d2  To: 0x8Dc63ce8b979627C11f5EEf673990814D4815613"
time="2018-08-13T15:59:04+08:00" level=info msg="Exported HexTx to /Users/hww/tx/signed/signed_from.0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce.json"

The transaction we constructed is signed and export json file to /Users/hww/tx/signed/ folder, copy the result to broadcast the signed sendTransaction.

broadcast signed transacion

▶ eth-cold-wallet send
time="2018-08-13T16:03:18+08:00" level=warning Note="all operate is recorded" Time:="Mon Aug 13 16:03:18 2018"
time="2018-08-13T16:03:18+08:00" level=info Time:="Mon Aug 13 16:03:18 2018" Using Configure file=/Users/hww/eth-cold-wallet.yml
time="2018-08-13T16:03:18+08:00" level=info msg="send tx:  0xbdfece2382b6e08c265928578b11b00292582670ad5b2c7a90243267b892d41b success"

log show we have send the transacion successfully, now we query the tx related addresses balance in web3 console:

from 0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce should be 0
to 0x8Dc63ce8b979627C11f5EEf673990814D4815613 should be 30 - fee

> web3.fromWei(web3.eth.getBalance("0xe5379d64Cd7d2D963B03da01fB052218a9aCB0Ce"),"ether")
0
> web3.fromWei(web3.eth.getBalance("0x8Dc63ce8b979627C11f5EEf673990814D4815613"),"ether")
29.999999999999979