pool/clientdb/codec.go
Wilmer Paulino 4021b2919c multi: tweak trader key with shared secret and per-batch key
In this commit, we overhaul the keys used in the multi-sig construction
of an account to prevent script reuse and provide plausible deniability
between account outputs to third parties. This is done by tweaking the
trader's key with two new components:

1. A per-batch key, which is obtained from the auctioneer during account
creation. Every time the account is modified or participates in a
cleared batch within the system, the per-batch key is incremented by the
curve's base point, resulting in a different key used in the account
script.

2. A shared secret derived using Diffie-Hellman between the trader's and
auctioneer's base keys. By using this secret, we provide plausible
deniability to third parties with knowledge of the base keys and
per-batch key.

The resulting tweaked key for the trader is then used as the tweak for
the auctioneer's base key.
2020-01-29 13:23:15 -08:00

170 lines
3.8 KiB
Go

package clientdb
import (
"encoding/binary"
"io"
"github.com/lightninglabs/agora/client/account"
"github.com/lightninglabs/agora/client/order"
"github.com/lightningnetwork/lnd/keychain"
"github.com/lightningnetwork/lnd/lntypes"
"github.com/lightningnetwork/lnd/lnwallet/chainfee"
"github.com/lightningnetwork/lnd/lnwire"
)
// WriteElements is writes each element in the elements slice to the passed
// io.Writer using WriteElement.
func WriteElements(w io.Writer, elements ...interface{}) error {
for _, element := range elements {
err := WriteElement(w, element)
if err != nil {
return err
}
}
return nil
}
// WriteElement is a one-stop shop to write the big endian representation of
// any element which is to be serialized. The passed io.Writer should be backed
// by an appropriately sized byte slice, or be able to dynamically expand to
// accommodate additional data.
func WriteElement(w io.Writer, element interface{}) error {
switch e := element.(type) {
case account.State:
return lnwire.WriteElement(w, uint8(e))
case order.Version:
return lnwire.WriteElement(w, uint32(e))
case order.Type:
return lnwire.WriteElement(w, uint8(e))
case order.State:
return lnwire.WriteElement(w, uint8(e))
case order.SupplyUnit:
return lnwire.WriteElement(w, uint64(e))
case chainfee.SatPerKWeight:
return lnwire.WriteElement(w, uint64(e))
case *keychain.KeyDescriptor:
if err := WriteElements(w, e.KeyLocator, e.PubKey); err != nil {
return err
}
case keychain.KeyLocator:
if err := binary.Write(w, byteOrder, e.Family); err != nil {
return err
}
if err := binary.Write(w, byteOrder, e.Index); err != nil {
return err
}
case lntypes.Preimage:
return lnwire.WriteElement(w, e[:])
case [32]byte:
return lnwire.WriteElement(w, e[:])
default:
return lnwire.WriteElement(w, element)
}
return nil
}
// ReadElements deserializes a variable number of elements into the passed
// io.Reader, with each element being deserialized according to the ReadElement
// function.
func ReadElements(r io.Reader, elements ...interface{}) error {
for _, element := range elements {
err := ReadElement(r, element)
if err != nil {
return err
}
}
return nil
}
// ReadElement is a one-stop utility function to deserialize any data structure.
func ReadElement(r io.Reader, element interface{}) error {
switch e := element.(type) {
case *account.State:
var s uint8
if err := lnwire.ReadElement(r, &s); err != nil {
return err
}
*e = account.State(s)
case *order.Version:
var v uint32
if err := lnwire.ReadElement(r, &v); err != nil {
return err
}
*e = order.Version(v)
case *order.Type:
var v uint8
if err := lnwire.ReadElement(r, &v); err != nil {
return err
}
*e = order.Type(v)
case *order.State:
var s uint8
if err := lnwire.ReadElement(r, &s); err != nil {
return err
}
*e = order.State(s)
case *order.SupplyUnit:
var s uint64
if err := lnwire.ReadElement(r, &s); err != nil {
return err
}
*e = order.SupplyUnit(s)
case *chainfee.SatPerKWeight:
var v uint64
if err := lnwire.ReadElement(r, &v); err != nil {
return err
}
*e = chainfee.SatPerKWeight(v)
case **keychain.KeyDescriptor:
var keyDesc keychain.KeyDescriptor
err := ReadElements(r, &keyDesc.KeyLocator, &keyDesc.PubKey)
if err != nil {
return err
}
*e = &keyDesc
case *keychain.KeyLocator:
if err := binary.Read(r, byteOrder, &e.Family); err != nil {
return err
}
if err := binary.Read(r, byteOrder, &e.Index); err != nil {
return err
}
case *lntypes.Preimage:
var preimage lntypes.Preimage
if err := lnwire.ReadElement(r, preimage[:]); err != nil {
return err
}
*e = preimage
case *[32]byte:
var b [32]byte
if err := lnwire.ReadElement(r, b[:]); err != nil {
return err
}
*e = b
default:
return lnwire.ReadElement(r, element)
}
return nil
}