feat: auto pad the length of the key

Author: leeqvip

aes.go

@@ -1,12 +1,14 @@
 package openssl
 
 import (
+	"bytes"
 	"crypto/aes"
+	"crypto/cipher"
 )
 
 // AesECBEncrypt
 func AesECBEncrypt(src, key []byte, padding string) ([]byte, error) {
-	block, err := aes.NewCipher(key)
+	block, err := AesNewCipher(key)
 	if err != nil {
 		return nil, err
 	}
@@ -15,7 +17,7 @@ func AesECBEncrypt(src, key []byte, padding string) ([]byte, error) {
 
 // AesECBDecrypt
 func AesECBDecrypt(src, key []byte, padding string) ([]byte, error) {
-	block, err := aes.NewCipher(key)
+	block, err := AesNewCipher(key)
 	if err != nil {
 		return nil, err
 	}
@@ -25,7 +27,7 @@ func AesECBDecrypt(src, key []byte, padding string) ([]byte, error) {
 
 // AesCBCEncrypt
 func AesCBCEncrypt(src, key, iv []byte, padding string) ([]byte, error) {
-	block, err := aes.NewCipher(key)
+	block, err := AesNewCipher(key)
 	if err != nil {
 		return nil, err
 	}
@@ -35,10 +37,37 @@ func AesCBCEncrypt(src, key, iv []byte, padding string) ([]byte, error) {
 
 // AesCBCDecrypt
 func AesCBCDecrypt(src, key, iv []byte, padding string) ([]byte, error) {
-	block, err := aes.NewCipher(key)
+	block, err := AesNewCipher(key)
 	if err != nil {
 		return nil, err
 	}
 
 	return CBCDecrypt(block, src, iv, padding)
 }
+
+// AesNewCipher creates and returns a new AES cipher.Block.
+// it will automatically pad the length of the key.
+func AesNewCipher(key []byte) (cipher.Block, error) {
+	return aes.NewCipher(aesKeyPending(key))
+}
+
+// aesKeyPending The length of the key can be 16/24/32 characters (128/192/256 bits)
+func aesKeyPending(key []byte) []byte {
+	k := len(key)
+	count := 0
+	switch true {
+	case k <= 16:
+		count = 16 - k
+	case k <= 24:
+		count = 24 - k
+	case k <= 32:
+		count = 32 - k
+	default:
+		return key[:32]
+	}
+	if count == 0 {
+		return key
+	}
+
+	return append(key, bytes.Repeat([]byte{0}, count)...)
+}

aes_test.go

@@ -3,6 +3,7 @@ package openssl
 import (
 	"encoding/base64"
 	"github.com/stretchr/testify/assert"
+	"reflect"
 	"testing"
 )
 
@@ -94,3 +95,26 @@ func TestAesCBCDecrypt(t *testing.T) {
 	t.Log(string(dst))
 	assert.Equal(t, dst, []byte("123456"))
 }
+
+func Test_aesKeyPending(t *testing.T) {
+	type args struct {
+		key []byte
+	}
+	tests := []struct {
+		name string
+		args args
+		want []byte
+	}{
+		{name: "key < 16", args: args{key: []byte("12354678901234")}, want: append([]byte("12354678901234"), []byte{0, 0}...)},
+		{name: "key < 24", args: args{key: []byte("1235467890123546789012")}, want: append([]byte("1235467890123546789012"), []byte{0, 0}...)},
+		{name: "key < 32", args: args{key: []byte("123546789012354678901235467890")}, want: append([]byte("123546789012354678901235467890"), []byte{0, 0}...)},
+		{name: "key > 32", args: args{key: []byte("1235467890123546789012354678901234")}, want: []byte("12354678901235467890123546789012")},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := aesKeyPending(tt.args.key); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("aesKeyPending() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

cbc.go

@@ -1,8 +1,8 @@
 package openssl
 
 import (
+	"bytes"
 	"crypto/cipher"
-	"errors"
 )
 
 // CBCEncrypt
@@ -13,7 +13,9 @@ func CBCEncrypt(block cipher.Block, src, iv []byte, padding string) ([]byte, err
 	encryptData := make([]byte, len(src))
 
 	if len(iv) != block.BlockSize() {
-		return nil, errors.New("CBCEncrypt: IV length must equal block size")
+		// auto pad length to block size
+		iv = cbcIVPending(iv, block.BlockSize())
+		//return nil, errors.New("CBCEncrypt: IV length must equal block size")
 	}
 
 	mode := cipher.NewCBCEncrypter(block, iv)
@@ -28,11 +30,25 @@ func CBCDecrypt(block cipher.Block, src, iv []byte, padding string) ([]byte, err
 	dst := make([]byte, len(src))
 
 	if len(iv) != block.BlockSize() {
-		return nil, errors.New("CBCDecrypt: IV length must equal block size")
+		// auto pad length to block size
+		iv = cbcIVPending(iv, block.BlockSize())
+		//return nil, errors.New("CBCDecrypt: IV length must equal block size")
 	}
 
 	mode := cipher.NewCBCDecrypter(block, iv)
 	mode.CryptBlocks(dst, src)
 
 	return UnPadding(padding, dst)
 }
+
+// cbcIVPending auto pad length to block size
+func cbcIVPending(iv []byte, blockSize int)[]byte  {
+	k := len(iv)
+	if k < blockSize{
+		return append(iv, bytes.Repeat([]byte{0}, blockSize - k)...)
+	}else if k > blockSize{
+		return iv[0: blockSize]
+	}
+
+	return iv
+}

des.go

@@ -1,12 +1,14 @@
 package openssl
 
 import (
+	"bytes"
+	"crypto/cipher"
 	"crypto/des"
 )
 
 // DesECBEncrypt
 func DesECBEncrypt(src, key []byte, padding string) ([]byte, error) {
-	block, err := des.NewCipher(key)
+	block, err := DesNewCipher(key)
 	if err != nil {
 		return nil, err
 	}
@@ -15,7 +17,7 @@ func DesECBEncrypt(src, key []byte, padding string) ([]byte, error) {
 
 // DesECBDecrypt
 func DesECBDecrypt(src, key []byte, padding string) ([]byte, error) {
-	block, err := des.NewCipher(key)
+	block, err := DesNewCipher(key)
 	if err != nil {
 		return nil, err
 	}
@@ -25,7 +27,7 @@ func DesECBDecrypt(src, key []byte, padding string) ([]byte, error) {
 
 // DesCBCEncrypt
 func DesCBCEncrypt(src, key, iv []byte, padding string) ([]byte, error) {
-	block, err := des.NewCipher(key)
+	block, err := DesNewCipher(key)
 	if err != nil {
 		return nil, err
 	}
@@ -35,10 +37,21 @@ func DesCBCEncrypt(src, key, iv []byte, padding string) ([]byte, error) {
 
 // DesCBCDecrypt
 func DesCBCDecrypt(src, key, iv []byte, padding string) ([]byte, error) {
-	block, err := des.NewCipher(key)
+	block, err := DesNewCipher(key)
 	if err != nil {
 		return nil, err
 	}
 
 	return CBCDecrypt(block, src, iv, padding)
 }
+
+// DesNewCipher creates and returns a new DES cipher.Block.
+func DesNewCipher(key []byte) (cipher.Block, error) {
+	if len(key) < 8 {
+		key = append(key, bytes.Repeat([]byte{0}, 8-len(key))...)
+	} else if len(key) > 8 {
+		key = key[:8]
+	}
+
+	return des.NewCipher(key)
+}