func SignFactoidTransaction(n uint64, tx interfaces.ITransaction) {
tx.AddAuthorization(NewFactoidRCDAddress(n))
data, err := tx.MarshalBinarySig()
if err != nil {
panic(err)
}
sig := factoid.NewSingleSignatureBlock(NewPrivKey(n), data)
//str, err := sig.JSONString()
//fmt.Printf("sig, err - %v, %v\n", str, err)
tx.SetSignatureBlock(0, sig)
err = tx.Validate(1)
if err != nil {
panic(err)
}
err = tx.ValidateSignatures()
if err != nil {
panic(err)
}
}