status-im/status-go

package peers

import (
    "crypto/ecdsa"
    "crypto/rand"
    "crypto/sha256"
    "encoding/json"

    udpp2p "github.com/schollz/peerdiscovery"

    "github.com/status-im/status-go/protocol/protobuf"
)

type LocalPairingPeerHello struct {
    protobuf.LocalPairingPeerHello
    Discovered udpp2p.Discovered
}

func NewLocalPairingPeerHello(id []byte, name, deviceType string, k *ecdsa.PrivateKey) (*LocalPairingPeerHello, error) {
    h := new(LocalPairingPeerHello)

    h.PeerId = id
    h.DeviceName = name
    h.DeviceType = deviceType

    err := h.sign(k)
    if err != nil {
        return nil, err
    }

    return h, nil
}

func (h *LocalPairingPeerHello) MarshalJSON() ([]byte, error) {
    alias := struct {
        PeerID     []byte
        DeviceName string
        DeviceType string
        Address    string
    }{
        PeerID:     h.PeerId,
        DeviceName: h.DeviceName,
        DeviceType: h.DeviceType,
        Address:    h.Discovered.Address,
    }

    return json.Marshal(alias)
}

func (h *LocalPairingPeerHello) hash() []byte {
    dHash := sha256.Sum256(append(h.PeerId, []byte(h.DeviceName+h.DeviceType)...))
    return dHash[:]
}

func (h *LocalPairingPeerHello) sign(k *ecdsa.PrivateKey) error {
    s, err := ecdsa.SignASN1(rand.Reader, k, h.hash())
    if err != nil {
        return err
    }

    h.Signature = s
    return nil
}

func (h *LocalPairingPeerHello) verify(k *ecdsa.PublicKey) bool {
    return ecdsa.VerifyASN1(k, h.hash(), h.Signature)
}