From bb860728a861e099ad3b73ac5eda359c57a897a8 Mon Sep 17 00:00:00 2001
From: thanhpp <thanhphanphu18@gmail.com>
Date: Thu, 21 Mar 2024 14:48:48 +0700
Subject: [PATCH] =?UTF-8?q?feat:=20=E2=9C=A8=20eth:=20RecoverSignerAddress?=
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Signed-off-by: thanhpp <thanhphanphu18@gmail.com>
---
 go.mod                  |  1 +
 go.sum                  |  2 ++
 pkg/eth/recover.go      | 44 +++++++++++++++++++++++++++++++++++++++++
 pkg/eth/recover_test.go | 18 +++++++++++++++++
 4 files changed, 65 insertions(+)
 create mode 100644 pkg/eth/recover.go
 create mode 100644 pkg/eth/recover_test.go

diff --git a/go.mod b/go.mod
index 561ddba..6f540a2 100644
--- a/go.mod
+++ b/go.mod
@@ -12,6 +12,7 @@ require (
 	github.com/shopspring/decimal v1.3.1
 	github.com/sourcegraph/conc v0.3.0
 	github.com/stretchr/testify v1.8.4
+	github.com/test-go/testify v1.1.4
 	golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa
 )
 
diff --git a/go.sum b/go.sum
index 2ca42f9..3d4c504 100644
--- a/go.sum
+++ b/go.sum
@@ -208,6 +208,8 @@ github.com/supranational/blst v0.3.11 h1:LyU6FolezeWAhvQk0k6O/d49jqgO52MSDDfYgbe
 github.com/supranational/blst v0.3.11/go.mod h1:jZJtfjgudtNl4en1tzwPIV3KjUnQUvG3/j+w+fVonLw=
 github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7 h1:epCh84lMvA70Z7CTTCmYQn2CKbY8j86K7/FAIr141uY=
 github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7/go.mod h1:q4W45IWZaF22tdD+VEXcAWRA037jwmWEB5VWYORlTpc=
+github.com/test-go/testify v1.1.4 h1:Tf9lntrKUMHiXQ07qBScBTSA0dhYQlu83hswqelv1iE=
+github.com/test-go/testify v1.1.4/go.mod h1:rH7cfJo/47vWGdi4GPj16x3/t1xGOj2YxzmNQzk2ghU=
 github.com/tidwall/gjson v1.8.1 h1:8j5EE9Hrh3l9Od1OIEDAb7IpezNA20UdRngNAj5N0WU=
 github.com/tidwall/gjson v1.8.1/go.mod h1:5/xDoumyyDNerp2U36lyolv46b3uF/9Bu6OfyQ9GImk=
 github.com/tidwall/match v1.0.3 h1:FQUVvBImDutD8wJLN6c5eMzWtjgONK9MwIBCOrUJKeE=
diff --git a/pkg/eth/recover.go b/pkg/eth/recover.go
new file mode 100644
index 0000000..7e61a4f
--- /dev/null
+++ b/pkg/eth/recover.go
@@ -0,0 +1,44 @@
+package eth
+
+import (
+	"fmt"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+const signatureLength = 65
+
+func RecoverSignerAddress(hexEncodedHash string, hexEncodedSignature string) (common.Address, error) {
+	hash, err := hexutil.Decode(hexEncodedHash)
+	if err != nil {
+		return common.Address{}, fmt.Errorf("decode hash error: %w", err)
+	}
+
+	signature, err := hexutil.Decode(hexEncodedSignature)
+	if err != nil {
+		return common.Address{}, fmt.Errorf("decode signature error: %w", err)
+	}
+
+	// Signature in Ethereum consists of R, S, V; the V is at last byte, R and S are the rest.
+	// The standard Ethereum signature is 65 bytes (R: 32 bytes, S: 32 bytes, V: 1 byte).
+	// Ensure the signature is 65 bytes and split it into R, S, and V components.
+	if len(signature) != signatureLength {
+		return common.Address{}, fmt.Errorf("invalid signature length, expect: %d, got: %v", signatureLength, len(signature))
+	}
+
+	// Ethereum uses a 'recovery id' for V, but go-ethereum expects V to be 27 or 28.
+	signature[64] -= 27
+
+	// Recover the public key from the signature
+	pubKey, err := crypto.SigToPub(hash, signature)
+	if err != nil {
+		return common.Address{}, fmt.Errorf("signature to public key error: %w", err)
+	}
+
+	// Derive the Ethereum address from the public key
+	address := crypto.PubkeyToAddress(*pubKey)
+
+	return address, nil
+}
diff --git a/pkg/eth/recover_test.go b/pkg/eth/recover_test.go
new file mode 100644
index 0000000..d311a14
--- /dev/null
+++ b/pkg/eth/recover_test.go
@@ -0,0 +1,18 @@
+package eth_test
+
+import (
+	"testing"
+
+	"github.com/KyberNetwork/tradinglib/pkg/eth"
+	"github.com/test-go/testify/require"
+)
+
+func TestRecover(t *testing.T) {
+	hashHex := "0xef6777697377372751e5daa1772d3b2b03f6f50b85dd3d7a79b4f12381897ec8"
+	signatureHex := "0xf89e6165aa337b8ebf74effa1a2b0980cc54e3780af077337b12438f30c901ab69ad655518007bd15073c919780ac61d3a4d5918c8966ffdb07256776ca6223f1c" // nolint: lll
+
+	addr, err := eth.RecoverSignerAddress(hashHex, signatureHex)
+	require.NoError(t, err)
+
+	t.Log(addr.String())
+}