Converts Geth proof of work chain spec e.g.

{
	"nonce": "0x0000000000000042",
	"timestamp": "0x0",
	"parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
	"extraData": "0x0",
	"gasLimit": "0x8000000",
	"difficulty": "0x400",
	"mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
	"coinbase": "0x3333333333333333333333333333333333333333",
	"alloc": {
		"0000000000000000000000000000000000000001": {"balance": "1"},
		"0000000000000000000000000000000000000002": {"balance": "1"},
		"0000000000000000000000000000000000000003": {"balance": "1"},
		"0000000000000000000000000000000000000004": {"balance": "1"},
		"dbdbdb2cbd23b783741e8d7fcf51e459b497e4a6": {"balance": "1606938044258990275541962092341162602522202993782792835301376"},
		"e4157b34ea9615cfbde6b4fda419828124b70c78": {"balance": "1606938044258990275541962092341162602522202993782792835301376"}
	}
}

to Parity one, which should enable the two to connect to each other. For best effects use the "config" field in Geth spec as seen in the Ropsten testnet spec.

Usage

If you do not have Cargo, best to use Rustup.

git clone https://github.com/keorn/parity-spec.git
cd parity-spec
cargo run -- geth-spec.json

The resulting spec can be then used in Parity with parity --chain parity-spec.json.