mirror of
https://source.quilibrium.com/quilibrium/ceremonyclient.git
synced 2024-12-27 09:05:18 +00:00
80 lines
1.9 KiB
Go
80 lines
1.9 KiB
Go
//
|
|
// Copyright Coinbase, Inc. All Rights Reserved.
|
|
//
|
|
// SPDX-License-Identifier: Apache-2.0
|
|
//
|
|
|
|
package bbs
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
|
|
"source.quilibrium.com/quilibrium/monorepo/nekryptology/pkg/core/curves"
|
|
"source.quilibrium.com/quilibrium/monorepo/nekryptology/pkg/signatures/common"
|
|
)
|
|
|
|
// BlindSignature is a BBS+ blind signature
|
|
// structurally identical to `Signature` but
|
|
// is used to help avoid misuse and confusion.
|
|
//
|
|
// 1 or more message have been hidden by the
|
|
// potential signature holder so the signer
|
|
// only knows a subset of the messages to be signed
|
|
type BlindSignature struct {
|
|
a curves.PairingPoint
|
|
e, s curves.Scalar
|
|
}
|
|
|
|
// Init creates an empty signature to a specific curve
|
|
// which should be followed by UnmarshalBinary
|
|
func (sig *BlindSignature) Init(curve *curves.PairingCurve) *BlindSignature {
|
|
sig.a = curve.NewG1IdentityPoint()
|
|
sig.e = curve.NewScalar()
|
|
sig.s = curve.NewScalar()
|
|
return sig
|
|
}
|
|
|
|
func (sig BlindSignature) MarshalBinary() ([]byte, error) {
|
|
out := append(sig.a.ToAffineCompressed(), sig.e.Bytes()...)
|
|
out = append(out, sig.s.Bytes()...)
|
|
return out, nil
|
|
}
|
|
|
|
func (sig *BlindSignature) UnmarshalBinary(data []byte) error {
|
|
pointLength := len(sig.a.ToAffineCompressed())
|
|
scalarLength := len(sig.s.Bytes())
|
|
expectedLength := pointLength + scalarLength*2
|
|
if len(data) != expectedLength {
|
|
return fmt.Errorf("invalid byte sequence")
|
|
}
|
|
a, err := sig.a.FromAffineCompressed(data[:pointLength])
|
|
if err != nil {
|
|
return err
|
|
}
|
|
e, err := sig.e.SetBytes(data[pointLength:(pointLength + scalarLength)])
|
|
if err != nil {
|
|
return err
|
|
}
|
|
s, err := sig.s.SetBytes(data[(pointLength + scalarLength):])
|
|
if err != nil {
|
|
return err
|
|
}
|
|
var ok bool
|
|
sig.a, ok = a.(curves.PairingPoint)
|
|
if !ok {
|
|
return errors.New("incorrect type conversion")
|
|
}
|
|
sig.e = e
|
|
sig.s = s
|
|
return nil
|
|
}
|
|
|
|
func (sig BlindSignature) ToUnblinded(blinder common.SignatureBlinding) *Signature {
|
|
return &Signature{
|
|
a: sig.a,
|
|
e: sig.e,
|
|
s: sig.s.Add(blinder),
|
|
}
|
|
}
|