Hyperledger FireFly Signer

A set of Ethereum transaction signing utilities designed for use across projects:

Go API libraries

• RLP Encoding and Decoding
  • See pkg/rlp go doc
• ABI Encoding and Decoding
  • Validation of ABI definitions
  • JSON <-> Value Tree <-> ABI Bytes
  • Model API exposed, as well as encode/decode APIs
  • See pkg/abi go doc
• Secp256k1 transaction signing for Ethereum transactions
  • Original
  • EIP-155
  • EIP-1559
  • EIP-712 (see below)
  • See pkg/ethsigner go doc
• EIP-712 Typed Data implementation
  • See pkg/eip712 go doc
• Keystore V3 key file implementation
  • Scrypt - read/write
  • pbkdf2 - read
  • See pkg/keystorev3 go doc
• Filesystem wallet
  • Configurable caching for in-memory keys
  • Files in directory with a given extension matching {{ADDRESS}}.key/{{ADDRESS}}.toml or arbitrary regex
  • Files can be TOML/YAML/JSON metadata pointing to Keystore V3 files + password files
  • Files can be Keystore V3 files directly, with accompanying {{ADDRESS}}.pass files
  • Detects newly added files automatically
  • See pkg/fswallet go doc
• JSON/RPC client
  • HTTP
  • WebSockets - with eth_subscribe support
  • See pkg/rpcbackend go doc

JSON/RPC proxy server

A runtime JSON/RPC server/proxy to intercept eth_sendTransaction JSON/RPC calls, and pass other calls through unchanged.

• Lightweight fast-starting runtime
• HTTP/HTTPS server
  • All HTTPS/CORS etc. features from FireFly Microservice framework
  • Configured via YAML
  • Batch JSON/RPC support
• eth_sendTransaction implementation to sign transactions
  • If EIP-1559 gas price fields are specified uses 0x02 transactions, otherwise EIP-155
• Makes some JSON/RPC calls on application’s behalf
  • Queries Chain ID via net_version on startup
  • eth_accounts JSON/RPC method support
  • Trivial nonce management built-in (calls eth_getTransactionCount for each request)

JSON/RPC proxy server configuration

For a full list of configuration options see config.md

Example configuration

Two examples provided below:

Flat directory of keys

fileWallet:
    path: /data/keystore
    filenames:
        with0xPrefix: false
        primaryExt: '.key.json'
        passwordExt: '.password'
server:
    address: '127.0.0.1'
    port: 8545
backend:
    url: https://blockhain.rpc.endpoint/path

Directory containing TOML configurations

fileWallet:
    path: /data/keystore
    filenames:
        with0xPrefix: false
        primaryExt: '.toml'
  metadata:
        format: toml
        keyFileProperty: '{{ index .signing "key-file" }}'
        passwordFileProperty: '{{ index .signing "password-file" }}'
server:
    address: '127.0.0.1'
    port: 8545
backend:
    url: https://blockhain.rpc.endpoint/path

Example TOML:

[metadata]
description = "File based configuration"

[signing]
type = "file-based-signer"
key-file = "/data/keystore/1f185718734552d08278aa70f804580bab5fd2b4.key.json"
password-file = "/data/keystore/1f185718734552d08278aa70f804580bab5fd2b4.pwd"

License

Apache 2.0

References / credits

JSON/RPC proxy

The JSON/RPC proxy and RLP encoding code was contributed by Kaleido, Inc.

Cryptography

secp256k1 cryptography libraries are provided by btcsuite (ISC Licensed):

https://pkg.go.dev/github.com/btcsuite/btcd/btcec

RLP encoding and keystore

Reference during implementation was made to the web3j implementation of Ethereum RLP encoding, and Keystore V3 wallet files (Apache 2.0 licensed):

https://github.com/web3j/web3j