1package bellmanverifier
  2
  3import (
  4	"bytes"
  5	"encoding/hex"
  6	"encoding/json"
  7	"fmt"
  8	"math/big"
  9	"strings"
 10
 11	bn256 "github.com/ethereum/go-ethereum/crypto/bn256/cloudflare"
 12)
 13
 14type Vk struct {
 15	Alpha    *bn256.G1
 16	Beta     *bn256.G2
 17	Gamma    *bn256.G2
 18	Delta    *bn256.G2
 19	GammaABC []*bn256.G1
 20}
 21
 22type VkRaw struct {
 23	Alpha    []string   `json:"alpha_g1"`
 24	Beta     [][]string `json:"beta_g2"`
 25	Gamma    [][]string `json:"gamma_g2"`
 26	Delta    [][]string `json:"delta_g2"`
 27	GammaABC [][]string `json:"ic"`
 28}
 29
 30type Proof struct {
 31	A *bn256.G1
 32	B *bn256.G2
 33	C *bn256.G1
 34}
 35
 36type ProofRaw struct {
 37	A      []string   `json:"a"`
 38	B      [][]string `json:"b"`
 39	C      []string   `json:"c"`
 40	Inputs []string   `json:"inputs"`
 41}
 42
 43func hexToG1(h []string) (*bn256.G1, error) {
 44	in := ""
 45	for i := range h {
 46		in += strings.TrimPrefix(h[i], "0x")
 47	}
 48
 49	b, err := hex.DecodeString(in)
 50	if err != nil {
 51		return nil, err
 52	}
 53	p := new(bn256.G1)
 54	_, err = p.Unmarshal(b)
 55
 56	return p, err
 57}
 58
 59func hexToG2Regular(h [][]string) (*bn256.G2, error) {
 60	in := ""
 61	for i := 0; i < len(h); i++ {
 62		for j := 0; j < len(h[i]); j++ {
 63			in += strings.TrimPrefix(h[i][j], "0x")
 64		}
 65	}
 66
 67	b, err := hex.DecodeString(in)
 68	if err != nil {
 69		return nil, err
 70	}
 71	p := new(bn256.G2)
 72	_, err = p.Unmarshal(b)
 73	return p, err
 74}
 75
 76func hexToG2(h [][]string) (*bn256.G2, error) {
 77	in := ""
 78	in += strings.TrimPrefix(h[0][1], "0x") // note that values are switched
 79	in += strings.TrimPrefix(h[0][0], "0x")
 80	in += strings.TrimPrefix(h[1][1], "0x")
 81	in += strings.TrimPrefix(h[1][0], "0x")
 82
 83	b, err := hex.DecodeString(in)
 84	if err != nil {
 85		return nil, err
 86	}
 87	p := new(bn256.G2)
 88	_, err = p.Unmarshal(b)
 89	return p, err
 90}
 91
 92func stringToBigInt(s string) *big.Int {
 93	base := 10
 94	if bytes.HasPrefix([]byte(s), []byte("0x")) {
 95		base = 16
 96		s = strings.TrimPrefix(s, "0x")
 97	}
 98	n, ok := new(big.Int).SetString(s, base)
 99	if !ok {
100		panic(fmt.Errorf("Can not parse string to *big.Int: %s", s))
101	}
102	return n
103}
104
105func parsePublicRaw(pj []byte) ([]*big.Int, error) {
106	var pr []string
107	err := json.Unmarshal(pj, &pr)
108	if err != nil {
109		return nil, err
110	}
111	var public []*big.Int
112	for _, s := range pr {
113		public = append(public, stringToBigInt(s))
114	}
115	return public, nil
116}
117
118// ParseVkRaw takes a json []byte and outputs the *Vk struct
119func ParseVkRaw(vj []byte) (*Vk, error) {
120	var vr VkRaw
121	err := json.Unmarshal(vj, &vr)
122	if err != nil {
123		return nil, err
124	}
125	v, err := vkRawToVk(vr)
126	return v, err
127}
128
129// ParseProofRaw takes a json []byte and outputs the *Proof struct
130func ParseProofRaw(pj []byte) (*Proof, error) {
131	var pr ProofRaw
132	err := json.Unmarshal(pj, &pr)
133	if err != nil {
134		return nil, err
135	}
136	p, err := proofRawToProof(pr)
137	return p, err
138}
139
140func vkRawToVk(vr VkRaw) (*Vk, error) {
141	var v Vk
142	var err error
143	v.Alpha, err = hexToG1(vr.Alpha)
144	if err != nil {
145		return nil, err
146	}
147
148	v.Beta, err = hexToG2(vr.Beta)
149	if err != nil {
150		return nil, err
151	}
152
153	v.Gamma, err = hexToG2(vr.Gamma)
154	if err != nil {
155		return nil, err
156	}
157
158	v.Delta, err = hexToG2(vr.Delta)
159	if err != nil {
160		return nil, err
161	}
162
163	for i := 0; i < len(vr.GammaABC); i++ {
164		p, err := hexToG1(vr.GammaABC[i])
165		if err != nil {
166			return nil, err
167		}
168		v.GammaABC = append(v.GammaABC, p)
169	}
170
171	return &v, nil
172}
173
174func proofRawToProof(pr ProofRaw) (*Proof, error) {
175	var p Proof
176	var err error
177	p.A, err = hexToG1(pr.A)
178	if err != nil {
179		return nil, err
180	}
181
182	p.B, err = hexToG2(pr.B)
183	if err != nil {
184		return nil, err
185	}
186
187	p.C, err = hexToG1(pr.C)
188	if err != nil {
189		return nil, err
190	}
191
192	return &p, nil
193}