From dd69d3293004fe0513e61d83574a556e3accfd01 Mon Sep 17 00:00:00 2001
From: Sun Yimin <emmansun@users.noreply.github.com>
Date: Tue, 25 Mar 2025 08:49:56 +0800
Subject: [PATCH] drbg: replace with for range

---
 drbg/ctr_drbg.go  | 14 +++++++-------
 drbg/hash_drbg.go |  4 ++--
 drbg/hmac_drbg.go |  2 +-
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/drbg/ctr_drbg.go b/drbg/ctr_drbg.go
index f55e917..26b64e7 100644
--- a/drbg/ctr_drbg.go
+++ b/drbg/ctr_drbg.go
@@ -120,12 +120,12 @@ func (hd *CtrDrbg) MaxBytesPerRequest() int {
 }
 
 // Generate CTR DRBG pseudorandom bits generate process.
-func (hd *CtrDrbg) Generate(b, additional []byte) error {
+func (hd *CtrDrbg) Generate(out, additional []byte) error {
 	if hd.NeedReseed() {
 		return ErrReseedRequired
 	}
 	outlen := len(hd.v)
-	if (hd.gm && len(b) > outlen) || (!hd.gm && len(b) > MAX_BYTES_PER_GENERATE) {
+	if (hd.gm && len(out) > outlen) || (!hd.gm && len(out) > MAX_BYTES_PER_GENERATE) {
 		return errors.New("drbg: too many bytes requested")
 	}
 
@@ -140,14 +140,14 @@ func (hd *CtrDrbg) Generate(b, additional []byte) error {
 	block := hd.newBlockCipher(hd.key)
 	temp := make([]byte, outlen)
 
-	m := len(b)
+	m := len(out)
 	limit := uint64(m+outlen-1) / uint64(outlen)
-	for i := 0; i < int(limit); i++ {
+	for i := range int(limit) {
 		// V = (V + 1) mod 2^outlen)
 		addOne(hd.v, outlen)
 		// output_block = Encrypt(Key, V)
 		block.Encrypt(temp, hd.v)
-		copy(b[i*outlen:], temp)
+		copy(out[i*outlen:], temp)
 	}
 	hd.update(additional)
 	hd.reseedCounter++
@@ -162,7 +162,7 @@ func (cd *CtrDrbg) update(seedMaterial []byte) {
 	v := make([]byte, outlen)
 	output := make([]byte, outlen)
 	copy(v, cd.v)
-	for i := 0; i < (cd.seedLength+outlen-1)/outlen; i++ {
+	for i := range (cd.seedLength+outlen-1)/outlen {
 		// V = (V + 1) mod 2^outlen
 		addOne(v, outlen)
 		// output_block = Encrypt(Key, V)
@@ -191,7 +191,7 @@ func (cd *CtrDrbg) derive(seedMaterial []byte, returnBytes int) []byte {
 	S[outlen+8+len(seedMaterial)] = 0x80
 
 	key := make([]byte, cd.keyLen)
-	for i := 0; i < cd.keyLen; i++ {
+	for i := range cd.keyLen {
 		key[i] = byte(i)
 	}
 	blocks := (cd.seedLength + outlen - 1) / outlen
diff --git a/drbg/hash_drbg.go b/drbg/hash_drbg.go
index a8d51da..dcc0d19 100644
--- a/drbg/hash_drbg.go
+++ b/drbg/hash_drbg.go
@@ -187,7 +187,7 @@ func (hd *HashDrbg) Generate(b, additional []byte) error {
 		limit := uint64(m+md.Size()-1) / uint64(md.Size())
 		data := make([]byte, hd.seedLength)
 		copy(data, hd.v)
-		for i := 0; i < int(limit); i++ {
+		for i := range int(limit) {
 			md.Write(data)
 			copy(b[i*md.Size():], md.Sum(nil))
 			addOne(data, hd.seedLength)
@@ -211,7 +211,7 @@ func (hd *HashDrbg) derive(seedMaterial []byte, len int) []byte {
 	byteorder.BEPutUint32(requireBytes[:], uint32(len<<3))
 	var ct byte = 1
 	k := make([]byte, len)
-	for i := 0; i < int(limit); i++ {
+	for i := range int(limit) {
 		// Hash( counter_byte || return_bits || seed_material )
 		md.Write([]byte{ct})
 		md.Write(requireBytes[:])
diff --git a/drbg/hmac_drbg.go b/drbg/hmac_drbg.go
index b19ccb6..6b39db5 100644
--- a/drbg/hmac_drbg.go
+++ b/drbg/hmac_drbg.go
@@ -45,7 +45,7 @@ func NewHmacDrbg(newHash func() hash.Hash, securityLevel SecurityLevel, gm bool,
 	// HMAC_DRBG_Instantiate_process
 	hd.key = make([]byte, hd.hashSize)
 	hd.v = make([]byte, hd.hashSize)
-	for i := 0; i < hd.hashSize; i++ {
+	for i := range hd.hashSize {
 		hd.key[i] = 0x00
 		hd.v[i] = 0x01
 	}