key_client_mock.go

// Copyright 2017 Monax Industries Limited
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package mock

import (
	"crypto/rand"
	"encoding/hex"
	"fmt"

	. "github.com/hyperledger/burrow/keys"

	// NOTE: prior to building out /crypto, use
	// tendermint/go-crypto for the mock client
	"github.com/tendermint/ed25519"
	"golang.org/x/crypto/ripemd160"
)

//---------------------------------------------------------------------
// Mock ed25510 key for mock keys client

// Simple ed25519 key structure for mock purposes with ripemd160 address
type MockKey struct {
	Address    []byte
	PrivateKey [ed25519.PrivateKeySize]byte
	PublicKey  []byte
}

func newMockKey() (*MockKey, error) {
	key := &MockKey{
		Address:   make([]byte, 20),
		PublicKey: make([]byte, ed25519.PublicKeySize),
	}
	// this is a mock key, so the entropy of the source is purely
	// for testing
	publicKey, privateKey, err := ed25519.GenerateKey(rand.Reader)
	if err != nil {
		return nil, err
	}
	copy(key.PrivateKey[:], privateKey[:])
	copy(key.PublicKey[:], publicKey[:])

	// prepend 0x01 for ed25519 public key
	typedPublicKeyBytes := append([]byte{0x01}, key.PublicKey...)
	hasher := ripemd160.New()
	hasher.Write(typedPublicKeyBytes)
	key.Address = hasher.Sum(nil)
	return key, nil
}

func (mockKey *MockKey) Sign(message []byte) ([]byte, error) {
	signatureBytes := make([]byte, ed25519.SignatureSize)
	signature := ed25519.Sign(&mockKey.PrivateKey, message)
	copy(signatureBytes[:], signature[:])
	return signatureBytes, nil
}

//---------------------------------------------------------------------
// Mock client for replacing signing done by monax-keys

// Implementation assertion
var _ KeyClient = (*MockKeyClient)(nil)

type MockKeyClient struct {
	knownKeys map[string]*MockKey
}

func NewMockKeyClient() *MockKeyClient {
	return &MockKeyClient{
		knownKeys: make(map[string]*MockKey),
	}
}

func (mock *MockKeyClient) NewKey() (address []byte) {
	// Only tests ED25519 curve and ripemd160.
	key, err := newMockKey()
	if err != nil {
		panic(fmt.Sprintf("Mocked key client failed on key generation: %s", err))
	}
	mock.knownKeys[fmt.Sprintf("%X", key.Address)] = key
	return key.Address
}

func (mock *MockKeyClient) Sign(signBytesString string, signAddress []byte) ([]byte, error) {
	key := mock.knownKeys[fmt.Sprintf("%X", signAddress)]
	if key == nil {
		return nil, fmt.Errorf("Unknown address (%X)", signAddress)
	}
	signBytes, err := hex.DecodeString(signBytesString)
	if err != nil {
		return nil, fmt.Errorf("Sign bytes string is invalid hex string: %s", err.Error())
	}
	return key.Sign(signBytes)
}

func (mock *MockKeyClient) PublicKey(address []byte) (publicKey []byte, err error) {
	key := mock.knownKeys[fmt.Sprintf("%X", address)]
	if key == nil {
		return nil, fmt.Errorf("Unknown address (%X)", address)
	}
	return key.PublicKey, nil
}