add simpler API to nizk stages

1 files changed, 21 insertions, 13 deletions

diff --git a/nizk/stage1/stage1.go b/nizk/stage1/stage1.go
index 0bd3e29..5c729c8 100644
--- a/nizk/stage1/stage1.go
+++ b/nizk/stage1/stage1.go
@@ -10,12 +10,12 @@ import (
 // for given Z, X, Y, R, C, A and B
 
 type Statement struct {
-	x    *Scalar
-	y    *Scalar
-	r    *Scalar
-	α    *Scalar
-	β    *Scalar
-	plus bool
+	x      *Scalar
+	y      *Scalar
+	r      *Scalar
+	α      *Scalar
+	β      *Scalar
+	bitSet bool
 	*Commitment
 }
 
@@ -29,22 +29,30 @@ type Commitment struct {
 	Z *Point
 }
 
-func NewStatement(x, y, r, α, β *Scalar, plus bool) *Statement {
+func NewStatement(bitSet bool) *Statement {
+	var x [5]*Scalar
+	for i := range x {
+		x[i] = Curve.RandomScalar()
+	}
+	return NewStatementFromScalars(bitSet, x[0], x[1], x[2], x[3], x[4])
+}
+
+func NewStatementFromScalars(bitSet bool, x, y, r, α, β *Scalar) *Statement {
 	return &Statement{
 		x:          x,
 		y:          y,
 		r:          r,
 		α:          α,
 		β:          β,
-		plus:       plus,
-		Commitment: commitment(x, y, r, α, β, plus),
+		bitSet:     bitSet,
+		Commitment: commitment(x, y, r, α, β, bitSet),
 	}
 }
 
-func commitment(x, y, r, α, β *Scalar, plus bool) *Commitment {
+func commitment(x, y, r, α, β *Scalar, bitSet bool) *Commitment {
 	var Z *Point
 	φ := α.Mul(β)
-	if plus {
+	if bitSet {
 		Z = G.Exp(x.Mul(r))
 		φ = φ.Add(One)
 	} else {
@@ -78,7 +86,7 @@ func (s *Statement) Proof() *Proof {
 		*s = Curve.RandomScalar()
 	}
 
-	if s.plus {
+	if s.bitSet {
 		ε[0][0] = G.Exp(r1).Mul(s.X.Exp(ω))
 		ε[0][1] = G.Exp(r2).Mul(s.A.Exp(ω))
 		ε[0][2] = s.Y.Exp(r1).Mul(s.Z.Exp(ω))
@@ -109,7 +117,7 @@ func (s *Statement) Proof() *Proof {
 	ch := Challenge(p...)
 	pr := &Proof{}
 
-	if s.plus {
+	if s.bitSet {
 		pr.Ch[0] = ω
 		pr.Ch[1] = ch.Sub(ω)
 		pr.Rho[0][0] = r1