Ejemplo n.º 1
0
// signStatement signs the contents passed in the io.Reader
// (pass an io.File or use an strings.NewReader for strings). It uses
// the roster el to create the collective signature.
// In case the signature fails, an error is returned.
func signStatement(read io.Reader, el *onet.Roster) (*service.SignatureResponse,
	error) {
	//publics := entityListToPublics(el)
	client := service.NewClient()
	msg, _ := crypto.HashStream(network.Suite.Hash(), read)

	pchan := make(chan *service.SignatureResponse)
	var err error
	go func() {
		log.Lvl3("Waiting for the response on SignRequest")
		response, e := client.SignatureRequest(el, msg)
		if e != nil {
			err = e
			close(pchan)
			return
		}
		pchan <- response
	}()

	select {
	case response, ok := <-pchan:
		log.Lvl5("Response:", response)
		if !ok || err != nil {
			return nil, errors.New("received an invalid response")
		}
		err = cosi.VerifySignature(network.Suite, el.Publics(), msg, response.Signature)
		if err != nil {
			return nil, err
		}
		return response, nil
	case <-time.After(RequestTimeOut):
		return nil, errors.New("timeout on signing request")
	}
}
Ejemplo n.º 2
0
// verifySignatureHash verifies if the message b is correctly signed by signature
// sig from roster el.
// If the signature-check fails for any reason, an error is returned.
func verifySignatureHash(b []byte, sig *service.SignatureResponse, el *onet.Roster) error {
	// We have to hash twice, as the hash in the signature is the hash of the
	// message sent to be signed
	//publics := entityListToPublics(el)
	fHash, _ := crypto.HashBytes(network.Suite.Hash(), b)
	hashHash, _ := crypto.HashBytes(network.Suite.Hash(), fHash)
	if !bytes.Equal(hashHash, sig.Hash) {
		return errors.New("You are trying to verify a signature " +
			"belonging to another file. (The hash provided by the signature " +
			"doesn't match with the hash of the file.)")
	}
	err := cosi.VerifySignature(network.Suite, el.Publics(), fHash, sig.Signature)
	if err != nil {
		return errors.New("Invalid sig:" + err.Error())
	}
	return nil
}