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Diffstat (limited to 'nizk/commit/commit.go')
-rw-r--r--nizk/commit/commit.go65
1 files changed, 31 insertions, 34 deletions
diff --git a/nizk/commit/commit.go b/nizk/commit/commit.go
index 1fa653e..49690f2 100644
--- a/nizk/commit/commit.go
+++ b/nizk/commit/commit.go
@@ -6,42 +6,41 @@ import (
)
// This is a construction of a proof of a statement of the form
-// [(C = g^(ab)) && (A = g^a) && (Β = g^b)]
-// || [(C = g^(ab+1)) && (A = g^a) && (Β = g^b)]
+// [(C = g^(αβ)) && (A = g^α) && (Β = g^β)]
+// || [(C = g^(αβ+1)) && (A = g^α) && (Β = g^β)]
//
// for given C, A and B
-type Statement struct {
+type Bid struct {
bitSet bool
- a *Scalar
- b *Scalar
+ α *Scalar
+ β *Scalar
Commitment
}
type Commitment struct {
- C *Point
- A *Point
- B *Point
- Proof *Proof
+ A *Point // g^α
+ B *Point // g^β
+ C *Point // g^(ab)g^(bitSet)
}
-func NewStatement(bitSet bool) *Statement {
- a, b := Curve.RandomScalar(), Curve.RandomScalar()
- return NewStatementFromScalars(bitSet, a, b)
+func NewBid(bitSet bool) *Bid {
+ α, β := Curve.RandomScalar(), Curve.RandomScalar()
+ return NewBidFromScalars(bitSet, α, β)
}
-func NewStatementFromScalars(bitSet bool, a, b *Scalar) *Statement {
- return &Statement{
- a: a,
- b: b,
+func NewBidFromScalars(bitSet bool, α, β *Scalar) *Bid {
+ return &Bid{
+ α: α,
+ β: β,
bitSet: bitSet,
- Commitment: commitment(a, b, bitSet),
+ Commitment: commitment(α, β, bitSet),
}
}
-func commitment(a, b *Scalar, bitSet bool) Commitment {
+func commitment(α, β *Scalar, bitSet bool) Commitment {
var C *Point
- c := a.Mul(b)
+ c := α.Mul(β)
if bitSet {
C = G.Exp(c.Add(One))
@@ -50,27 +49,26 @@ func commitment(a, b *Scalar, bitSet bool) Commitment {
}
return Commitment{
C: C,
- A: G.Exp(a),
- B: G.Exp(b),
+ A: G.Exp(α),
+ B: G.Exp(β),
}
}
-func (s *Statement) Commit(id Bytes) *Commitment {
- s.Commitment.Proof = s.Proof(id)
- return &s.Commitment
+func (s *Bid) Commit(id Bytes) (*Commitment, *Proof) {
+ return &s.Commitment, s.Proof(id)
}
type Proof struct {
Id Bytes
- A *schnorr.Proof // Proof for knowledge of a in A = G^a
- B *schnorr.Proof // Proof for knowledge of b in B = G^b
+ A *schnorr.Proof // Proof for knowledge of α in A = G^α
+ B *schnorr.Proof // Proof for knowledge of β in B = G^β
C struct { // Proof for knowledge of statement above
Ch [2]*Scalar
R [2]*Scalar
}
}
-func (s *Statement) Proof(id Bytes) *Proof {
+func (s *Bid) Proof(id Bytes) *Proof {
var e [2][2]*Point
var r1, r2, w *Scalar
r1 = Curve.RandomScalar()
@@ -95,23 +93,22 @@ func (s *Statement) Proof(id Bytes) *Proof {
if s.bitSet {
pr.C.Ch[0] = w
pr.C.Ch[1] = ch.Sub(w)
- pr.C.R[0] = r1.Sub(s.a.Mul(pr.C.Ch[0]))
- pr.C.R[1] = r2.Sub(s.a.Mul(pr.C.Ch[1]))
+ pr.C.R[0] = r1.Sub(s.α.Mul(pr.C.Ch[0]))
+ pr.C.R[1] = r2.Sub(s.α.Mul(pr.C.Ch[1]))
} else {
pr.C.Ch[0] = ch.Sub(w)
pr.C.Ch[1] = w
- pr.C.R[0] = r1.Sub(s.a.Mul(pr.C.Ch[0]))
+ pr.C.R[0] = r1.Sub(s.α.Mul(pr.C.Ch[0]))
pr.C.R[1] = r2
}
- pr.A = (*schnorr.Statement)(s.a).Proof(id)
- pr.B = (*schnorr.Statement)(s.b).Proof(id)
+ pr.A = (*schnorr.Statement)(s.α).Proof(id)
+ pr.B = (*schnorr.Statement)(s.β).Proof(id)
return pr
}
-func (c *Commitment) Verify() bool {
+func (c *Commitment) Verify(p *Proof) bool {
var e [2][2]*Point
- p := c.Proof
e[0][0] = G.Exp(p.C.R[0]).Mul(c.A.Exp(p.C.Ch[0]))
e[0][1] = c.B.Exp(p.C.R[0]).Mul(c.C.Exp(p.C.Ch[0]))