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

hyperledger/firefly-signer