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