path: root/whisper/message.go

package whisper

import (
    "crypto/ecdsa"
    "time"

    "github.com/ethereum/go-ethereum/crypto"
)

type Message struct {
    Flags     byte
    Signature []byte
    Payload   []byte
}

func NewMessage(payload []byte) *Message {
    return &Message{Flags: 0, Payload: payload}
}

func (self *Message) hash() []byte {
    return crypto.Sha3(append([]byte{self.Flags}, self.Payload...))
}

func (self *Message) sign(key *ecdsa.PrivateKey) (err error) {
    self.Flags = 1
    self.Signature, err = crypto.Sign(self.hash(), key)
    return
}

func (self *Message) Recover() *ecdsa.PublicKey {
    defer func() { recover() }() // in case of invalid sig
    return crypto.SigToPub(self.hash(), self.Signature)
}

func (self *Message) Encrypt(to *ecdsa.PublicKey) (err error) {
    self.Payload, err = crypto.Encrypt(to, self.Payload)
    if err != nil {
        return err
    }

    return nil
}

func (self *Message) Bytes() []byte {
    return append([]byte{self.Flags}, append(self.Signature, self.Payload...)...)
}

type Opts struct {
    From   *ecdsa.PrivateKey
    To     *ecdsa.PublicKey
    Ttl    time.Duration
    Topics [][]byte
}

func (self *Message) Seal(pow time.Duration, opts Opts) (*Envelope, error) {
    if opts.From != nil {
        err := self.sign(opts.From)
        if err != nil {
            return nil, err
        }
    }

    if opts.To != nil {
        err := self.Encrypt(opts.To)
        if err != nil {
            return nil, err
        }
    }

    if opts.Ttl == 0 {
        opts.Ttl = DefaultTtl
    }

    envelope := NewEnvelope(opts.Ttl, opts.Topics, self)
    envelope.Seal(pow)

    return envelope, nil
}