func getReqSigDataHash(req *msg.OcReq) ([]byte, error) {
var buf bytes.Buffer
req.WriteSignablePortion(&buf)
hasher := sha256.New()
_, err := hasher.Write(buf.Bytes())
if err != nil {
return nil, fmt.Errorf("error while hashing: %v", err.Error())
}
h := hasher.Sum([]byte{})
return h, nil
}
