1package common
 2
 3import (
 4	"time"
 5
 6	ethCommon "github.com/ethereum/go-ethereum/common"
 7	ethCrypto "github.com/ethereum/go-ethereum/crypto"
 8	"github.com/hermeznetwork/tracerr"
 9	"github.com/iden3/go-iden3-crypto/babyjub"
10)
11
12// AccountCreationAuth authorizations sent by users to the L2DB, to be used for account creations when necessary
13type AccountCreationAuth struct {
14	EthAddr   ethCommon.Address  `meddler:"eth_addr"`
15	BJJ       *babyjub.PublicKey `meddler:"bjj"`
16	Signature []byte             `meddler:"signature"`
17	Timestamp time.Time          `meddler:"timestamp,utctime"`
18}
19
20// HashToSign builds the hash to be signed using BJJ pub key and the constant message
21func (a *AccountCreationAuth) HashToSign() ([]byte, error) {
22	// Calculate message to be signed
23	const msg = "I authorize this babyjubjub key for hermez rollup account creation"
24	comp, err := a.BJJ.Compress().MarshalText()
25	if err != nil {
26		return nil, tracerr.Wrap(err)
27	}
28	// Hash message (msg || compressed-bjj)
29	return ethCrypto.Keccak256Hash([]byte(msg), comp).Bytes(), nil
30}
31
32// VerifySignature ensures that the Signature is done with the specified EthAddr
33func (a *AccountCreationAuth) VerifySignature() bool {
34	// Calculate hash to be signed
35	msg, err := a.HashToSign()
36	if err != nil {
37		return false
38	}
39	// Get public key from Signature
40	pubKBytes, err := ethCrypto.Ecrecover(msg, a.Signature)
41	if err != nil {
42		return false
43	}
44	pubK, err := ethCrypto.UnmarshalPubkey(pubKBytes)
45	if err != nil {
46		return false
47	}
48	// Get addr from pubK
49	addr := ethCrypto.PubkeyToAddress(*pubK)
50	return addr == a.EthAddr
51}