From e1db48e289045741bc6a403850b8cd69210df2cb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= <peterke@gmail.com>
Date: Tue, 20 Dec 2016 11:25:49 +0200
Subject: [PATCH] accounts, core, crypto: fun with docs to make things explicit

---
 accounts/account_manager.go       |  4 ++--
 core/types/transaction_signing.go | 12 ++++++------
 crypto/crypto.go                  |  7 ++-----
 3 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/accounts/account_manager.go b/accounts/account_manager.go
index bd7175aa918a2..12ff30bcaf564 100644
--- a/accounts/account_manager.go
+++ b/accounts/account_manager.go
@@ -137,7 +137,7 @@ func (am *Manager) DeleteAccount(a Account, passphrase string) error {
 }
 
 // Sign calculates a ECDSA signature for the given hash. The produced signature
-// is in the canonical secp256k1 format (V = 0 or 1).
+// is in the [R || S || V] format where V is 0 or 1.
 func (am *Manager) Sign(addr common.Address, hash []byte) ([]byte, error) {
 	am.mu.RLock()
 	defer am.mu.RUnlock()
@@ -151,7 +151,7 @@ func (am *Manager) Sign(addr common.Address, hash []byte) ([]byte, error) {
 
 // SignWithPassphrase signs hash if the private key matching the given address
 // can be decrypted with the given passphrase. The produced signature is in the
-// canonical secp256k1 format (V = 0 or 1).
+// [R || S || V] format where V is 0 or 1.
 func (am *Manager) SignWithPassphrase(addr common.Address, passphrase string, hash []byte) (signature []byte, err error) {
 	_, key, err := am.getDecryptedKey(Account{Address: addr}, passphrase)
 	if err != nil {
diff --git a/core/types/transaction_signing.go b/core/types/transaction_signing.go
index f991667576b88..8952bd57470bd 100644
--- a/core/types/transaction_signing.go
+++ b/core/types/transaction_signing.go
@@ -161,8 +161,8 @@ func (s EIP155Signer) PublicKey(tx *Transaction) ([]byte, error) {
 	return pub, nil
 }
 
-// WithSignature returns a new transaction with the given signature.
-// This signature needs to be in the canonical secp256k1 form (v = 0 or 1).
+// WithSignature returns a new transaction with the given signature. This signature
+// needs to be in the [R || S || V] format where V is 0 or 1.
 func (s EIP155Signer) WithSignature(tx *Transaction, sig []byte) (*Transaction, error) {
 	if len(sig) != 65 {
 		panic(fmt.Sprintf("wrong size for snature: got %d, want 65", len(sig)))
@@ -211,8 +211,8 @@ func (s HomesteadSigner) Equal(s2 Signer) bool {
 	return ok
 }
 
-// WithSignature returns a new transaction with the given snature.
-// This signature needs to be in the canonical secp256k1 form (v = 0 or 1).
+// WithSignature returns a new transaction with the given signature. This signature
+// needs to be in the [R || S || V] format where V is 0 or 1.
 func (hs HomesteadSigner) WithSignature(tx *Transaction, sig []byte) (*Transaction, error) {
 	if len(sig) != 65 {
 		panic(fmt.Sprintf("wrong size for snature: got %d, want 65", len(sig)))
@@ -267,8 +267,8 @@ func (s FrontierSigner) Equal(s2 Signer) bool {
 	return ok
 }
 
-// WithSignature returns a new transaction with the given snature.
-// This signature needs to be in the canonical secp256k1 form (v = 0 or 1).
+// WithSignature returns a new transaction with the given signature. This signature
+// needs to be in the [R || S || V] format where V is 0 or 1.
 func (fs FrontierSigner) WithSignature(tx *Transaction, sig []byte) (*Transaction, error) {
 	if len(sig) != 65 {
 		panic(fmt.Sprintf("wrong size for snature: got %d, want 65", len(sig)))
diff --git a/crypto/crypto.go b/crypto/crypto.go
index 25aec0836f2e2..f1a4b774c0bc2 100644
--- a/crypto/crypto.go
+++ b/crypto/crypto.go
@@ -168,8 +168,7 @@ func GenerateKey() (*ecdsa.PrivateKey, error) {
 }
 
 // ValidateSignatureValues verifies whether the signature values are valid with
-// the given chain rules. The v value is assumed to be the canonical secp256k1
-// value of either 0 or 1.
+// the given chain rules. The v value is assumed to be either 0 or 1.
 func ValidateSignatureValues(v byte, r, s *big.Int, homestead bool) bool {
 	if r.Cmp(common.Big1) < 0 || s.Cmp(common.Big1) < 0 {
 		return false
@@ -200,9 +199,7 @@ func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) {
 // be aware that the given hash cannot be choosen by an adversery. Common
 // solution is to hash any input before calculating the signature.
 //
-// The produced signature is in the canonical secp256k1 format (V = 0 or 1),
-// which can be transformed into the proper Ethereum signature accoring to
-// the yellow paper within the transaction signer.
+// The produced signature is in the [R || S || V] format where V is 0 or 1.
 func Sign(data []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) {
 	if len(data) != 32 {
 		return nil, fmt.Errorf("hash is required to be exactly 32 bytes (%d)", len(data))