1package kzg
  2
  3import (
  4	"math/big"
  5	"testing"
  6
  7	"github.com/stretchr/testify/assert"
  8)
  9
 10func TestSimpleFlow(t *testing.T) {
 11	// p(x) = x^3 + x + 5
 12	p := []*big.Int{
 13		big.NewInt(5),
 14		big.NewInt(1), // x^1
 15		big.NewInt(0), // x^2
 16		big.NewInt(1), // x^3
 17	}
 18	assert.Equal(t, "x³ + x¹ + 5", PolynomialToString(p))
 19
 20	// TrustedSetup
 21	ts, err := NewTrustedSetup(len(p))
 22	assert.Nil(t, err)
 23
 24	// Commit
 25	c := Commit(ts, p)
 26
 27	// p(z)=y --> p(3)=35
 28	z := big.NewInt(3)
 29	y := big.NewInt(35)
 30
 31	// z & y: to prove an evaluation p(z)=y
 32	proof, err := EvaluationProof(ts, p, z, y)
 33	assert.Nil(t, err)
 34
 35	v := Verify(ts, c, proof, z, y)
 36	assert.True(t, v)
 37
 38	v = Verify(ts, c, proof, big.NewInt(4), y)
 39	assert.False(t, v)
 40}
 41
 42func TestBatchProof(t *testing.T) {
 43	// p(x) = x^3 + x + 5
 44	p := []*big.Int{
 45		big.NewInt(5),
 46		big.NewInt(1),  // x^1
 47		big.NewInt(0),  // x^2
 48		big.NewInt(1),  // x^3
 49		big.NewInt(10), // x^4
 50	}
 51	assert.Equal(t, "10x⁴ + x³ + x¹ + 5", PolynomialToString(p))
 52
 53	// TrustedSetup
 54	ts, err := NewTrustedSetup(len(p))
 55	assert.Nil(t, err)
 56
 57	// Commit
 58	c := Commit(ts, p)
 59
 60	// 1st point: p(z)=y --> p(3)=35
 61	z0 := big.NewInt(3)
 62	y0 := polynomialEval(p, z0)
 63
 64	// 2nd point: p(10)=1015
 65	z1 := big.NewInt(10)
 66	y1 := polynomialEval(p, z1)
 67
 68	// 3nd point: p(256)=16777477
 69	z2 := big.NewInt(256)
 70	y2 := polynomialEval(p, z2)
 71
 72	zs := []*big.Int{z0, z1, z2}
 73	ys := []*big.Int{y0, y1, y2}
 74
 75	// prove an evaluation of the multiple z_i & y_i
 76	proof, err := EvaluationBatchProof(ts, p, zs, ys)
 77	assert.Nil(t, err)
 78
 79	// batch proof verification
 80	v := VerifyBatchProof(ts, c, proof, zs, ys)
 81	assert.True(t, v)
 82
 83	// changing order of the points to be verified
 84	zs[0], zs[1], zs[2] = zs[1], zs[2], zs[0]
 85	ys[0], ys[1], ys[2] = ys[1], ys[2], ys[0]
 86	v = VerifyBatchProof(ts, c, proof, zs, ys)
 87	assert.True(t, v)
 88
 89	// change a value of zs and check that verification fails
 90	zs[0] = big.NewInt(2)
 91	v = VerifyBatchProof(ts, c, proof, zs, ys)
 92	assert.False(t, v)
 93
 94	// using a value that is not in the evaluation proof should generate a
 95	// proof that will not correctly be verified
 96	zs = []*big.Int{z0, z1, z2}
 97	ys = []*big.Int{y0, y1, y2}
 98	proof, err = EvaluationBatchProof(ts, p, zs, ys)
 99	assert.Nil(t, err)
100	zs[2] = big.NewInt(2500)
101	ys[2] = polynomialEval(p, zs[2])
102	v = VerifyBatchProof(ts, c, proof, zs, ys)
103	assert.False(t, v)
104}