Switching to a different ristretto implementation
the build failed Details

This commit is contained in:
Sarah Jamie Lewis 2019-10-07 22:57:45 -07:00
parent 136b9b8192
commit 9332385a6f
6 changed files with 222 additions and 166 deletions

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@ -4,7 +4,7 @@ import (
"cwtch.im/tapir/primitives/core"
"encoding/json"
"git.openprivacy.ca/openprivacy/libricochet-go/log"
"github.com/bwesterb/go-ristretto"
ristretto "github.com/gtank/ristretto255"
"strconv"
)
@ -12,12 +12,12 @@ import (
type InnerProductProof struct {
L core.PointVector
R core.PointVector
A core.Scalar
B core.Scalar
A *ristretto.Scalar
B *ristretto.Scalar
}
// ProveInnerProduct generates a proof for <a,b>, the inner product of a and b
func ProveInnerProduct(a, b core.ScalarVector, u core.Point, P *ristretto.Point, G, H core.GeneratorVector, transcript *core.Transcript) InnerProductProof {
func ProveInnerProduct(a, b core.ScalarVector, u *ristretto.Element, P *ristretto.Element, G, H core.GeneratorVector, transcript *core.Transcript) InnerProductProof {
n := len(a)
transcript.AddToTranscript("n", []byte(strconv.Itoa(n)))
Lvec := core.PointVector{}
@ -26,7 +26,7 @@ func ProveInnerProduct(a, b core.ScalarVector, u core.Point, P *ristretto.Point,
transcript.AddToTranscript("G", Gbytes)
Hbytes, _ := json.Marshal(H)
transcript.AddToTranscript("H", Hbytes)
transcript.AddToTranscript("P'", P.Bytes())
transcript.AddToTranscript("P'", []byte(P.String()))
for n != 1 {
np := n / 2
aL, aR := a[:np], a[np:]
@ -40,30 +40,31 @@ func ProveInnerProduct(a, b core.ScalarVector, u core.Point, P *ristretto.Point,
L := core.MultiExp(append(aL.Join(bR), cL), append(GR.Join(HL), u))
R := core.MultiExp(append(aR.Join(bL), cR), append(GL.Join(HR), u))
transcript.AddToTranscript("L", L.Bytes())
transcript.AddToTranscript("L", []byte(L.String()))
Lvec = append(Lvec, L)
transcript.AddToTranscript("R", R.Bytes())
transcript.AddToTranscript("R",[]byte(R.String()))
Rvec = append(Rvec, R)
u := transcript.CommitToTranscriptScalar("u")
uinv := new(ristretto.Scalar).Inverse(u)
uinv := new(ristretto.Scalar)
uinv.Invert(u)
for i := 0; i < len(aL); i++ {
aL_ := new(ristretto.Scalar).Mul(aL[i], u)
aL[i] = aL_.Add(aL_, new(ristretto.Scalar).Mul(aR[i], uinv))
bL_ := new(ristretto.Scalar).Mul(bL[i], uinv)
bL[i] = bL_.Add(bL_, new(ristretto.Scalar).Mul(bR[i], u))
aL_ := new(ristretto.Scalar).Multiply(aL[i], u)
aL[i] = new(ristretto.Scalar).Add(aL_, new(ristretto.Scalar).Multiply(aR[i], uinv))
bL_ := new(ristretto.Scalar).Multiply(bL[i], uinv)
bL[i] = new(ristretto.Scalar).Add(bL_, new(ristretto.Scalar).Multiply(bR[i], u))
GL[i] = core.MultiExp(core.ScalarVector{uinv, u}, core.GeneratorVector{GL[i], GR[i]})
HL[i] = core.MultiExp(core.ScalarVector{u, uinv}, core.GeneratorVector{HL[i], HR[i]})
}
x2 := new(ristretto.Scalar).Square(u)
P_ := new(ristretto.Point).ScalarMult(L, x2)
x2 := new(ristretto.Scalar).Multiply(u,u)
P_ := new(ristretto.Element).ScalarMult(x2,L)
P_.Add(P_, P)
P_.Add(P_, new(ristretto.Point).ScalarMult(R, new(ristretto.Scalar).Inverse(x2)))
P_.Add(P_, new(ristretto.Element).ScalarMult(new(ristretto.Scalar).Invert(x2),R))
P = P_
transcript.AddToTranscript("P'", P.Bytes())
transcript.AddToTranscript("P'", []byte(P.String()))
a = aL
b = bL
@ -80,7 +81,7 @@ func ProveInnerProduct(a, b core.ScalarVector, u core.Point, P *ristretto.Point,
}
// Verify checks the given inner product proof
func Verify(proof InnerProductProof, n int, u, P *ristretto.Point, G, H core.GeneratorVector, transcript *core.Transcript) bool {
func Verify(proof InnerProductProof, n int, u, P *ristretto.Element, G, H core.GeneratorVector, transcript *core.Transcript) bool {
transcript.AddToTranscript("n", []byte(strconv.Itoa(n)))
np := n / 2
@ -88,27 +89,28 @@ func Verify(proof InnerProductProof, n int, u, P *ristretto.Point, G, H core.Gen
transcript.AddToTranscript("G", Gbytes)
Hbytes, _ := json.Marshal(H)
transcript.AddToTranscript("H", Hbytes)
transcript.AddToTranscript("P'", P.Bytes())
transcript.AddToTranscript("P'", []byte(P.String()))
for i := range proof.L {
GL, GR := G[:np], G[np:]
HL, HR := H[:np], H[np:]
transcript.AddToTranscript("L", proof.L[i].Bytes())
transcript.AddToTranscript("R", proof.R[i].Bytes())
transcript.AddToTranscript("L", []byte(proof.L[i].String()))
transcript.AddToTranscript("R", []byte(proof.R[i].String()))
x := transcript.CommitToTranscriptScalar("u")
xinv := new(ristretto.Scalar).Inverse(x)
xinv := new(ristretto.Scalar)
xinv.Invert(x)
for j := 0; j < np; j++ {
GL[j] = core.MultiExp(core.ScalarVector{xinv, x}, core.GeneratorVector{GL[j], GR[j]})
HL[j] = core.MultiExp(core.ScalarVector{x, xinv}, core.GeneratorVector{HL[j], HR[j]})
}
x2 := new(ristretto.Scalar).Square(x)
P_ := new(ristretto.Point).ScalarMult(proof.L[i], x2)
x2 := new(ristretto.Scalar).Multiply(x,x)
P_ := new(ristretto.Element).ScalarMult(x2,proof.L[i])
P_.Add(P_, P)
P_.Add(P_, new(ristretto.Point).ScalarMult(proof.R[i], new(ristretto.Scalar).Inverse(x2)))
P_.Add(P_, new(ristretto.Element).ScalarMult(new(ristretto.Scalar).Invert(x2),proof.R[i]))
P = P_
transcript.AddToTranscript("P'", P.Bytes())
transcript.AddToTranscript("P'", []byte(P.String()))
G = GL
H = HL
@ -118,8 +120,9 @@ func Verify(proof InnerProductProof, n int, u, P *ristretto.Point, G, H core.Gen
transcript.AddToTranscript("H", Hbytes)
np = np / 2
}
c := new(ristretto.Scalar).Mul(proof.A, proof.B)
c := new(ristretto.Scalar)
c.Multiply(proof.A, proof.B)
P_ := core.MultiExp(core.ScalarVector{proof.A, proof.B, c}, core.GeneratorVector{G[0], H[0], u})
log.Debugf("P:%v\nP':%v\n", P, P_)
return P.Equals(P_)
return P.Equal(P_) == 1
}

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@ -3,12 +3,13 @@ package bulletproofs
import (
"cwtch.im/tapir/primitives/core"
"git.openprivacy.ca/openprivacy/libricochet-go/log"
"github.com/bwesterb/go-ristretto"
ristretto "github.com/gtank/ristretto255"
"testing"
)
func assert(t *testing.T, expected *ristretto.Scalar, actual *ristretto.Scalar) {
if expected.Equals(actual) {
if expected.Equal(actual) == 1 {
t.Logf("inner_product matched: %v", actual)
} else {
t.Fatalf("c should be %v instead: %v", expected, actual)
@ -16,8 +17,9 @@ func assert(t *testing.T, expected *ristretto.Scalar, actual *ristretto.Scalar)
}
func Test_inner_product(t *testing.T) {
one := new(ristretto.Scalar).SetOne()
zero := new(ristretto.Scalar).SetZero()
one := core.IdentityVector(1)[0]
zero := new(ristretto.Scalar)
zero.Zero()
a := core.ScalarVector{one, zero, one, zero}
b := core.ScalarVector{zero, one, zero, one}
c := core.InnerProduct(a, b)
@ -26,35 +28,42 @@ func Test_inner_product(t *testing.T) {
a = core.ScalarVector{one, one, one, zero}
b = core.ScalarVector{one, one, zero, one}
c = core.InnerProduct(a, b)
assert(t, new(ristretto.Scalar).Add(one, one), c)
check := new(ristretto.Scalar)
check.Add(one,one)
assert(t, check, c)
}
func TestProveInnerProduct(t *testing.T) {
log.SetLevel(log.LevelDebug)
one := new(ristretto.Scalar).SetOne()
zero := new(ristretto.Scalar).SetZero()
one := core.IdentityVector(1)[0]
zero := new(ristretto.Scalar)
zero.Zero()
a := core.ScalarVector{one, zero, one, one}
b := core.ScalarVector{zero, one, one, one}
c := core.InnerProduct(a, b)
G := make(core.GeneratorVector, 4)
H := make(core.GeneratorVector, 4)
for i := 0; i < 4; i++ {
G[i] = new(ristretto.Point).Rand()
H[i] = new(ristretto.Point).Rand()
}
u := new(ristretto.Point).Rand()
P_ := core.MultiExp(append(a.Join(b), c), append(G.Join(H), u))
proverTranscript := core.NewTranscript("test_innerproductproof")
verifierTranscript := core.NewTranscript("test_innerproductproof")
proof := ProveInnerProduct(a, b, u, new(ristretto.Point).Set(P_), core.CopyVector(G), core.CopyVector(H), proverTranscript)
if Verify(proof, 4, u, new(ristretto.Point).Set(P_), core.CopyVector(G), core.CopyVector(H), verifierTranscript) {
G := proverTranscript.CommitToGenerators("G",4)
H := proverTranscript.CommitToGenerators("H",4)
u := proverTranscript.CommitToGenerator("u")
verifierTranscript.CommitToGenerators("G",4)
verifierTranscript.CommitToGenerators("H",4)
verifierTranscript.CommitToGenerator("u")
c := core.InnerProduct(a,b)
P_ := core.MultiExp(append(a.Join(b), c), append(core.GeneratorVector(G).Join(core.GeneratorVector(H)), u))
proof := ProveInnerProduct(a, b, u, new(ristretto.Element).Add(new(ristretto.Element).Zero(), P_), core.CopyVector(G), core.CopyVector(H), proverTranscript)
if Verify(proof, 4, u, P_, core.CopyVector(G), core.CopyVector(H), verifierTranscript) {
t.Logf("Inner Product Proof Passed!")
} else {
t.Logf("%v\n\n%v\n", proverTranscript.OutputTranscriptToAudit(), verifierTranscript.OutputTranscriptToAudit())

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@ -1,32 +1,33 @@
package bulletproofs
import (
"crypto/rand"
"cwtch.im/tapir/primitives/core"
"git.openprivacy.ca/openprivacy/libricochet-go/log"
"github.com/bwesterb/go-ristretto"
ristretto "github.com/gtank/ristretto255"
"math/big"
)
// RangeProof encapsulates a proof that V = [0, max) where max is defined by the Setup function
type RangeProof struct {
A *ristretto.Point
S *ristretto.Point
T1 *ristretto.Point
T2 *ristretto.Point
A *ristretto.Element
S *ristretto.Element
T1 *ristretto.Element
T2 *ristretto.Element
TauX *ristretto.Scalar
InnerProduct *ristretto.Scalar
Mu *ristretto.Scalar
IPP InnerProductProof
V *ristretto.Point
V *ristretto.Element
}
// CommitmentsParams encapsulates the commitment parameters for a given range proof
type CommitmentsParams struct {
G core.GeneratorVector
H core.GeneratorVector
u *ristretto.Point
g *ristretto.Point
h *ristretto.Point
u *ristretto.Element
g *ristretto.Element
h *ristretto.Element
max int
}
@ -43,69 +44,92 @@ func Setup(max int, transcript *core.Transcript) (c CommitmentsParams) {
return
}
func Rand(seed string) *ristretto.Scalar {
t := core.NewTranscript(seed)
return t.CommitToTranscriptScalar("seed")
}
// GenerateRangeProof creates a valid rangeproof that value is within [0,max) under the given transcript
// It returns the rangeproof and a random scalar "gamma" that can be used to open V, the commitement to v vGgH
// It returns the rangeproof and a random scalar "gamma" that can be used to open V, the commitment to v vGgH
func GenerateRangeProof(value int32, c CommitmentsParams, transcript *core.Transcript) (RangeProof, *ristretto.Scalar) {
one := new(ristretto.Scalar).SetOne()
two := new(ristretto.Scalar).Add(one, one)
one := core.IdentityVector(1)[0]
two := new(ristretto.Scalar)
two.Add(one, one)
two_n := core.PowerVector(two, c.max)
gamma := new(ristretto.Scalar).Rand()
// Generate a prng to from this transcript and some external randomness
// We use this to generate the rest of our private scalars
// TODO: move to transcript
private := make([]byte,64)
rand.Read(private)
prngTranscript:= core.NewTranscript("private-transcript")
prngTranscript.AddToTranscript("randomness",private)
prng := prngTranscript.CommitToPRNG(transcript.OutputTranscriptToAudit())
gamma := prng.Next()
aL := valueToVector(value, c.max)
aR := core.VectorAddScalar(aL, new(ristretto.Scalar).Neg(one))
alpha := new(ristretto.Scalar).Rand()
aR := core.VectorAddScalar(aL, new(ristretto.Scalar).Negate(one))
alpha := prng.Next()
vs := new(ristretto.Scalar)
b := make([]byte,32)
copy(b,big.NewInt(int64(value)).Bytes())
vs.Decode(b)
vs := new(ristretto.Scalar).SetBigInt(big.NewInt(int64(value)))
V := core.MultiExp(core.ScalarVector{gamma, vs}, core.GeneratorVector{c.h, c.g})
A := core.MultiExp(append(aL.Join(aR), alpha), append(c.G.Join(c.H), c.h))
log.Debugf("vs: %v", vs)
Sl := make(core.ScalarVector, c.max)
Sr := make(core.ScalarVector, c.max)
for i := 0; i < c.max; i++ {
Sl[i] = new(ristretto.Scalar).Rand()
Sr[i] = new(ristretto.Scalar).Rand()
Sl[i] = prng.Next()
Sr[i] = prng.Next()
}
p := new(ristretto.Scalar).Rand()
p := prng.Next()
S := core.MultiExp(append(Sl.Join(Sr), p), append(c.G.Join(c.H), c.h))
transcript.AddToTranscript("A", A.Bytes())
transcript.AddToTranscript("S", S.Bytes())
transcript.AddToTranscript("A", []byte(A.String()))
transcript.AddToTranscript("S",[]byte(S.String()))
y := transcript.CommitToTranscriptScalar("y")
z := transcript.CommitToTranscriptScalar("z")
y_n := core.PowerVector(y, c.max)
z2 := new(ristretto.Scalar).Square(z)
z2 := new(ristretto.Scalar).Multiply(z,z)
l0 := core.VectorAddScalar(aL, new(ristretto.Scalar).Neg(z))
l0 := core.VectorAddScalar(aL, new(ristretto.Scalar).Negate(z))
//l1 == Sr
r0 := core.EntrywiseSum(core.EntryWiseProduct(y_n, core.VectorAddScalar(aR, z)), core.VectorMulScalar(two_n, z2))
r1 := core.EntryWiseProduct(Sr, y_n)
t0 := new(ristretto.Scalar).Add(new(ristretto.Scalar).Mul(z2, vs), delta(y_n, z, c.max))
t1 := new(ristretto.Scalar).Add(core.InnerProduct(Sl, r0), core.InnerProduct(l0, r1))
t0 := new(ristretto.Scalar).Add(new(ristretto.Scalar).Multiply(z2, vs), delta(y_n, z, c.max))
t1 := new(ristretto.Scalar)
t1.Add(core.InnerProduct(Sl, r0), core.InnerProduct(l0, r1))
t2 := core.InnerProduct(Sl, r1)
tau1 := new(ristretto.Scalar).Rand()
tau2 := new(ristretto.Scalar).Rand()
tau1 := prng.Next()
tau2 := prng.Next()
T1 := core.MultiExp(core.ScalarVector{t1, tau1}, core.GeneratorVector{c.g, c.h})
T2 := core.MultiExp(core.ScalarVector{t2, tau2}, core.GeneratorVector{c.g, c.h})
transcript.AddToTranscript("T1", T1.Bytes())
transcript.AddToTranscript("T2", T2.Bytes())
transcript.AddToTranscript("T1", []byte(T1.String()))
transcript.AddToTranscript("T2", []byte(T2.String()))
x := transcript.CommitToTranscriptScalar("x")
// T(X) = t0 + t1x + t2x
TX := new(ristretto.Scalar).Set(t0)
TX.Add(TX, new(ristretto.Scalar).Mul(t1, x))
TX.Add(TX, new(ristretto.Scalar).Mul(t2, new(ristretto.Scalar).Square(x)))
TX := new(ristretto.Scalar)
TX.Add(new(ristretto.Scalar).Zero(), t0)
TX.Add(TX, new(ristretto.Scalar).Multiply(t1, x))
TX.Add(TX, new(ristretto.Scalar).Multiply(t2, new(ristretto.Scalar).Multiply(x,x)))
l := core.EntrywiseSum(core.VectorAddScalar(aL, new(ristretto.Scalar).Neg(z)), core.VectorMulScalar(Sl, x))
l := core.EntrywiseSum(core.VectorAddScalar(aL, new(ristretto.Scalar).Negate(z)), core.VectorMulScalar(Sl, x))
_r := core.EntrywiseSum(core.VectorAddScalar(aR, z), core.VectorMulScalar(Sr, x))
r := core.EntrywiseSum(core.EntryWiseProduct(y_n, _r), core.VectorMulScalar(two_n, z2))
@ -113,103 +137,118 @@ func GenerateRangeProof(value int32, c CommitmentsParams, transcript *core.Trans
log.Debugf("T(X) = %v", TX)
log.Debugf("ipp = %v", iplr)
log.Debugf("equal: %v", TX.Equals(iplr))
log.Debugf("equal: %v", TX.Equal(iplr) == 1)
// generate h'
H_ := make(core.GeneratorVector, c.max)
H_[0] = c.H[0]
for i := 1; i < c.max; i++ {
H_[i] = new(ristretto.Point).ScalarMult(c.H[i], new(ristretto.Scalar).Inverse(y_n[i]))
H_[i] = new(ristretto.Element).ScalarMult(new(ristretto.Scalar).Invert(y_n[i]),c.H[i],)
}
P := core.MultiExp(l.Join(r), c.G.Join(H_))
log.Debugf("P: %v", P)
uP := new(ristretto.Point).Add(P, new(ristretto.Point).ScalarMult(c.u, iplr))
uP := new(ristretto.Element).Add(P, new(ristretto.Element).ScalarMult(iplr,c.u))
log.Debugf("uP: %v", uP)
ipp := ProveInnerProduct(l, r, c.u, new(ristretto.Point).Set(uP), core.CopyVector(c.G), core.CopyVector(H_), transcript)
ipp := ProveInnerProduct(l, r, c.u, new(ristretto.Element).Add(new(ristretto.Element).Zero(),uP), core.CopyVector(c.G), core.CopyVector(H_), transcript)
taux := new(ristretto.Scalar).Mul(tau2, new(ristretto.Scalar).Square(x))
taux = taux.Add(taux, new(ristretto.Scalar).Mul(tau1, x))
taux = taux.Add(taux, new(ristretto.Scalar).Mul(z2, gamma))
taux := new(ristretto.Scalar)
taux.Multiply(tau2, new(ristretto.Scalar).Multiply(x,x))
taux.Add(taux, new(ristretto.Scalar).Multiply(tau1, x))
taux.Add(taux, new(ristretto.Scalar).Multiply(z2, gamma))
mu := new(ristretto.Scalar).Add(alpha, new(ristretto.Scalar).Mul(p, x))
mu := new(ristretto.Scalar)
mu.Add(alpha, new(ristretto.Scalar).Multiply(p, x))
return RangeProof{A, S, T1, T2, taux, iplr, mu, ipp, V}, gamma
}
// VerifyRangeProof returns true if the given proof passes all the checks for a given set of commitment parameters
// and the given transcript
func VerifyRangeProof(proof RangeProof, c CommitmentsParams, transcript *core.Transcript) bool {
one := new(ristretto.Scalar).SetOne()
two := new(ristretto.Scalar).Add(one, one)
one := core.IdentityVector(1)[0]
two := new(ristretto.Scalar)
two.Add(one, one)
two_n := core.PowerVector(two, c.max)
transcript.AddToTranscript("A", proof.A.Bytes())
transcript.AddToTranscript("S", proof.S.Bytes())
transcript.AddToTranscript("A", []byte(proof.A.String()))
transcript.AddToTranscript("S",[]byte(proof.S.String()))
y := transcript.CommitToTranscriptScalar("y")
z := transcript.CommitToTranscriptScalar("z")
transcript.AddToTranscript("T1", proof.T1.Bytes())
transcript.AddToTranscript("T2", proof.T2.Bytes())
transcript.AddToTranscript("T1", []byte(proof.T1.String()))
transcript.AddToTranscript("T2", []byte(proof.T2.String()))
x := transcript.CommitToTranscriptScalar("x")
y_n := core.PowerVector(y, c.max)
// generate h'
H_ := make(core.GeneratorVector, c.max)
H_[0] = c.H[0]
for i := 1; i < c.max; i++ {
H_[i] = new(ristretto.Point).ScalarMult(c.H[i], new(ristretto.Scalar).Inverse(y_n[i]))
H_[i] = new(ristretto.Element).ScalarMult(new(ristretto.Scalar).Invert(y_n[i]),c.H[i],)
}
// check t = t(x) = t0 + t1.x + t1.x^2
lhs := core.MultiExp(core.ScalarVector{proof.InnerProduct, proof.TauX}, core.GeneratorVector{c.g, c.h})
rhs := core.MultiExp(core.ScalarVector{new(ristretto.Scalar).Square(z), delta(y_n, z, c.max), x, new(ristretto.Scalar).Square(x)}, core.GeneratorVector{proof.V, c.g, proof.T1, proof.T2})
z2 := new(ristretto.Scalar)
z2.Multiply(z,z)
x2 := new(ristretto.Scalar)
x2.Multiply(x,x)
rhs := core.MultiExp(core.ScalarVector{z2, delta(y_n, z, c.max), x, x2}, core.GeneratorVector{proof.V, c.g, proof.T1, proof.T2})
log.Debugf("lhs: %v", lhs)
log.Debugf("rhs: %v", rhs)
log.Debugf("equal: %v", lhs.Equals(rhs))
log.Debugf("equal: %v", lhs.Equal(rhs))
if lhs.Equals(rhs) {
if lhs.Equal(rhs) == 1{
// compute P
negz := new(ristretto.Scalar).Neg(z)
negzG := new(ristretto.Point).SetZero()
negz := new(ristretto.Scalar).Negate(z)
negzG := new(ristretto.Element).Zero()
for _, gen := range c.G {
negzG = negzG.Add(negzG, new(ristretto.Point).ScalarMult(gen, negz))
negzG = negzG.Add(negzG, new(ristretto.Element).ScalarMult(negz, gen))
}
mul := core.EntrywiseSum(core.VectorMulScalar(y_n, z), core.VectorMulScalar(two_n, new(ristretto.Scalar).Square(z)))
mul := core.EntrywiseSum(core.VectorMulScalar(y_n, z), core.VectorMulScalar(two_n, new(ristretto.Scalar).Multiply(z,z)))
Pr := new(ristretto.Point).Set(proof.A)
Pr = Pr.Add(Pr, new(ristretto.Point).ScalarMult(proof.S, x))
Pr := new(ristretto.Element).Add(new(ristretto.Element).Zero(),proof.A)
Pr = Pr.Add(Pr, new(ristretto.Element).ScalarMult(x,proof.S))
Pr = Pr.Add(Pr, negzG)
Pr = Pr.Add(Pr, core.MultiExp(mul, H_))
Pl := new(ristretto.Point).Sub(Pr, new(ristretto.Point).ScalarMult(c.h, proof.Mu))
Pl := new(ristretto.Element).Subtract(Pr, new(ristretto.Element).ScalarMult(proof.Mu,c.h))
// check inner product
uP := new(ristretto.Point).Add(Pl, new(ristretto.Point).ScalarMult(c.u, proof.InnerProduct))
uP := new(ristretto.Element).Add(Pl, new(ristretto.Element).ScalarMult(proof.InnerProduct, c.u))
return Verify(proof.IPP, c.max, c.u, new(ristretto.Point).Set(uP), core.CopyVector(c.G), core.CopyVector(H_), transcript)
return Verify(proof.IPP, c.max, c.u, new(ristretto.Element).Add(new(ristretto.Element).Zero(),uP), core.CopyVector(c.G), core.CopyVector(H_), transcript)
}
return false
}
func delta(y_n core.ScalarVector, z core.Scalar, max int) core.Scalar {
one := new(ristretto.Scalar).SetOne()
func delta(y_n core.ScalarVector, z *ristretto.Scalar, max int) *ristretto.Scalar {
one := core.IdentityVector(1)[0]
// (z-z^2)
z2 := new(ristretto.Scalar).Square(z)
result := new(ristretto.Scalar).Sub(z, z2)
z2 := new(ristretto.Scalar).Multiply(z,z)
result := new(ristretto.Scalar)
result.Subtract(z, z2)
// (z-z^2) * <1^n,y^n>
result.Mul(result, core.InnerProduct(core.IdentityVector(max), y_n))
two := new(ristretto.Scalar).Add(one, one)
result.Multiply(result, core.InnerProduct(core.IdentityVector(max), y_n))
two := new(ristretto.Scalar)
two.Add(one, one)
two_n := core.PowerVector(two, max)
// (z-z^2) * <1^n,y^n> - z^3 *<1n,2n>
z3 := new(ristretto.Scalar).Mul(z2, z)
return result.Sub(result, new(ristretto.Scalar).Mul(z3, core.InnerProduct(core.IdentityVector(max), two_n)))
z3 := new(ristretto.Scalar).Multiply(z2, z)
result.Subtract(result, new(ristretto.Scalar).Multiply(z3, core.InnerProduct(core.IdentityVector(max), two_n)))
return result
}
func valueToVector(value int32, max int) core.ScalarVector {
one := new(ristretto.Scalar).SetOne()
zero := new(ristretto.Scalar).SetZero()
one := core.IdentityVector(1)[0]
zero := new(ristretto.Scalar)
zero.Zero()
result := core.ScalarVector{}
for len(result) != max {
v := value & 0x0001

View File

@ -23,5 +23,4 @@ func TestProove(t *testing.T) {
t.Logf("%v\n\n%v\n", proverTranscript.OutputTranscriptToAudit(), verifierTranscript.OutputTranscriptToAudit())
t.Fatalf("Failed to Verify Range Proof")
}
}

View File

@ -2,29 +2,27 @@ package core
import (
"fmt"
"github.com/bwesterb/go-ristretto"
ristretto "github.com/gtank/ristretto255"
)
// Scalar is short hand for a ristretto scalar
type Scalar *ristretto.Scalar
// Point is short hand of a ristretto point
type Point *ristretto.Point
// ScalarVector explicit type checking
type ScalarVector []Scalar
type ScalarVector []*ristretto.Scalar
// PointVector explicit type checking
type PointVector []*ristretto.Point
// ElementVector explicit type checking
type PointVector []*ristretto.Element
// GeneratorVector explicit type checking
type GeneratorVector []*ristretto.Point
type GeneratorVector []*ristretto.Element
// CopyVector safely copies a vector
func CopyVector(G GeneratorVector) GeneratorVector {
H := make(GeneratorVector, len(G))
for i, g := range G {
H[i] = new(ristretto.Point).Set(g)
H[i] = new(ristretto.Element).Add(new(ristretto.Element).Zero(), g)
}
return H
}
@ -35,23 +33,23 @@ func InnerProduct(a, b ScalarVector) *ristretto.Scalar {
panic(fmt.Sprintf("len(a) = %v ; len(b) = %v;", len(a), len(b)))
}
result := new(ristretto.Scalar).SetZero()
result := new(ristretto.Scalar).Zero()
for i, ai := range a {
result.Add(result, new(ristretto.Scalar).Mul(ai, b[i]))
result.Add(result, new(ristretto.Scalar).Multiply(ai, b[i]))
}
return result
}
// MultiExp takes in a vector of scalars = {a,b,c...} and a vector of generator = {A,B,C...} and outputs
// {aA,bB,cC}
func MultiExp(a ScalarVector, G GeneratorVector) *ristretto.Point {
func MultiExp(a ScalarVector, G GeneratorVector) *ristretto.Element {
if len(a) != len(G) {
panic(fmt.Sprintf("len(a) = %v ; len(b) = %v;", len(a), len(G)))
}
result := new(ristretto.Point).SetZero()
result := new(ristretto.Element).Zero()
for i, ai := range a {
aG := new(ristretto.Point).ScalarMult(G[i], ai)
result = new(ristretto.Point).Add(result, aG)
aG := new(ristretto.Element).ScalarMult(ai, G[i])
result = new(ristretto.Element).Add(result, aG)
}
return result
}
@ -60,10 +58,10 @@ func MultiExp(a ScalarVector, G GeneratorVector) *ristretto.Point {
func (a ScalarVector) Join(b ScalarVector) ScalarVector {
list := make(ScalarVector, len(a)+len(b))
for i := 0; i < len(a); i++ {
list[i] = new(ristretto.Scalar).Set(a[i])
list[i] = a[i]
}
for i := len(a); i < len(b)+len(b); i++ {
list[i] = new(ristretto.Scalar).Set(b[i-len(a)])
list[i] = b[i-len(a)]
}
return list
}
@ -72,10 +70,10 @@ func (a ScalarVector) Join(b ScalarVector) ScalarVector {
func (a GeneratorVector) Join(b GeneratorVector) GeneratorVector {
list := make(GeneratorVector, len(a)+len(b))
for i := 0; i < len(a); i++ {
list[i] = new(ristretto.Point).Set(a[i])
list[i] = a[i]
}
for i := len(a); i < len(b)+len(b); i++ {
list[i] = new(ristretto.Point).Set(b[i-len(a)])
list[i] = b[i-len(a)]
}
return list
}
@ -84,7 +82,8 @@ func (a GeneratorVector) Join(b GeneratorVector) GeneratorVector {
func VectorAddScalar(vector ScalarVector, scalar *ristretto.Scalar) ScalarVector {
result := make(ScalarVector, len(vector))
for i := range vector {
result[i] = new(ristretto.Scalar).Add(vector[i], scalar)
result[i] = new(ristretto.Scalar)
result[i].Add(vector[i], scalar)
}
return result
}
@ -93,7 +92,8 @@ func VectorAddScalar(vector ScalarVector, scalar *ristretto.Scalar) ScalarVector
func VectorMulScalar(vector ScalarVector, scalar *ristretto.Scalar) ScalarVector {
result := make(ScalarVector, len(vector))
for i := range vector {
result[i] = new(ristretto.Scalar).Mul(vector[i], scalar)
result[i] = new(ristretto.Scalar)
result[i].Multiply(vector[i], scalar)
}
return result
}
@ -102,7 +102,8 @@ func VectorMulScalar(vector ScalarVector, scalar *ristretto.Scalar) ScalarVector
func EntrywiseSum(vector ScalarVector, vector2 ScalarVector) ScalarVector {
result := make(ScalarVector, len(vector))
for i, v := range vector {
result[i] = new(ristretto.Scalar).Add(v, vector2[i])
result[i] = new(ristretto.Scalar)
result[i].Add(v, vector2[i])
}
return result
}
@ -111,7 +112,8 @@ func EntrywiseSum(vector ScalarVector, vector2 ScalarVector) ScalarVector {
func EntryWiseProduct(vector ScalarVector, vector2 ScalarVector) ScalarVector {
result := make(ScalarVector, len(vector))
for i, v := range vector {
result[i] = new(ristretto.Scalar).Mul(v, vector2[i])
result[i] = new(ristretto.Scalar)
result[i].Multiply(v, vector2[i])
}
return result
}
@ -119,8 +121,10 @@ func EntryWiseProduct(vector ScalarVector, vector2 ScalarVector) ScalarVector {
// IdentityVector is a convenience function to generate a vector v = {1,1,1...1}
func IdentityVector(n int) ScalarVector {
result := make(ScalarVector, n)
one := new(ristretto.Scalar)
one.Decode([]byte{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0})
for i := 0; i < n; i++ {
result[i] = new(ristretto.Scalar).SetOne()
result[i] = one
}
return result
}
@ -128,10 +132,13 @@ func IdentityVector(n int) ScalarVector {
// PowerVector creates a vector v = {1,x,x^2,x^3..x^n}
func PowerVector(x *ristretto.Scalar, n int) ScalarVector {
result := make(ScalarVector, n)
result[0] = new(ristretto.Scalar).SetOne()
result[1] = new(ristretto.Scalar).Set(x)
for i := 1; i < n; i++ {
result[i] = new(ristretto.Scalar).Mul(result[i-1], result[1])
one := new(ristretto.Scalar)
one.Decode([]byte{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0})
result[0] = one
result[1] = x
for i := 2; i < n; i++ {
result[i] = new(ristretto.Scalar)
result[i].Multiply(result[i-1], x)
}
return result
}
}

View File

@ -2,18 +2,17 @@ package core
import (
"fmt"
"github.com/bwesterb/go-ristretto"
ristretto "github.com/gtank/ristretto255"
"golang.org/x/crypto/sha3"
"hash"
"io"
)
// Transcript implements a transcript of a public coin argument.
// Transcript provides a consistent transcript primitive for our protocols
//
// We have the following goals:
// - Provide a consisted transcript API for our zero knowledge protocols
// - Allow sequential proofs over a common transcript (ensuring a single proof cannot be extracted standalone)
// - produce an auditable human-readable transcript.
// - be able to produce a human-readable transcript for auditing.
//
// The design of this API was inspired by Merlin: https://docs.rs/crate/merlin/
//
@ -26,7 +25,7 @@ type Transcript struct {
// NewTranscript creates a new Transcript with the given Label, the label should be unique to the application
func NewTranscript(label string) *Transcript {
transcript := new(Transcript)
transcript.hash = sha3.New256()
transcript.hash = sha3.New512()
transcript.AddToTranscript("protocol", []byte(label))
return transcript
}
@ -67,9 +66,11 @@ type PRNG struct {
// Next returns the next "random" scalar from the PRNG
func (prng *PRNG) Next() *ristretto.Scalar {
buf := [32]byte{}
buf := [64]byte{}
io.ReadFull(prng.prng, buf[:])
return new(ristretto.Scalar).SetBytes(&buf)
next := new(ristretto.Scalar)
next.FromUniformBytes(buf[:])
return next
}
// CommitToPRNG commits the label to the transcript and derives a PRNG from the transcript.
@ -83,15 +84,13 @@ func (t *Transcript) CommitToPRNG(label string) PRNG {
}
// CommitToGenerator derives a verifiably random generator from the transcript
func (t *Transcript) CommitToGenerator(label string) *ristretto.Point {
func (t *Transcript) CommitToGenerator(label string) *ristretto.Element {
c := t.CommitToTranscript(label)
cs := [32]byte{}
copy(cs[:], c[:])
return new(ristretto.Point).SetElligator(&cs)
return new(ristretto.Element).FromUniformBytes(c)
}
// CommitToGenerators derives a set of verifiably random generators from the transcript
func (t *Transcript) CommitToGenerators(label string, n int) (generators []*ristretto.Point) {
func (t *Transcript) CommitToGenerators(label string, n int) (generators []*ristretto.Element) {
for i := 0; i < n; i++ {
generators = append(generators, t.CommitToGenerator(fmt.Sprintf("%v-%d", label, i)))
}
@ -101,7 +100,7 @@ func (t *Transcript) CommitToGenerators(label string, n int) (generators []*rist
// CommitToTranscriptScalar is a convenience method for CommitToTranscript which returns a ristretto Scalar
func (t *Transcript) CommitToTranscriptScalar(label string) *ristretto.Scalar {
c := t.CommitToTranscript(label)
cs := [32]byte{}
copy(cs[:], c[:])
return new(ristretto.Scalar).SetBytes(&cs)
s := new(ristretto.Scalar)
s.FromUniformBytes(c[:])
return s
}