zuc: expose methods to support encoding.BinaryMarshaler and encoding.BinaryUnmarshaler

Author: emmansun

zuc/eea.go

@@ -53,3 +53,18 @@ func NewCipherWithBucketSize(key, iv []byte, bucketSize int) (cipher.SeekableStr
 func NewEEACipherWithBucketSize(key []byte, count, bearer, direction uint32, bucketSize int) (cipher.SeekableStream, error) {
 	return zuc.NewEEACipherWithBucketSize(key, count, bearer, direction, bucketSize)
 }
+
+// NewEmptyEEACipher creates and returns a new empty ZUC-EEA cipher instance.
+// This function initializes an empty eea struct that can be used for
+// unmarshaling a previously saved state using the UnmarshalBinary method.
+// The returned cipher instance is not ready for encryption or decryption.
+func NewEmptyEEACipher() cipher.SeekableStream {
+	return zuc.NewEmptyCipher()
+}
+
+// UnmarshalEEACipher reconstructs a ZUC cipher instance from a serialized byte slice.
+// It attempts to deserialize the provided data into a seekable stream cipher
+// that can be used for encryption/decryption operations.
+func UnmarshalEEACipher(data []byte) (cipher.SeekableStream, error) {
+	return zuc.UnmarshalCipher(data)
+}

zuc/eea_test.go

@@ -3,6 +3,7 @@ package zuc
 import (
 	"bytes"
 	"crypto/cipher"
+	"encoding"
 	"encoding/hex"
 	"testing"
 
@@ -113,9 +114,12 @@ func TestXORStreamAt(t *testing.T) {
 				t.Errorf("expected=%x, result=%x\n", expected[32:64], dst[32:64])
 			}
 		}
+		data, _ := c.(encoding.BinaryMarshaler).MarshalBinary()
+		c2 := NewEmptyEEACipher()
+		c2.(encoding.BinaryUnmarshaler).UnmarshalBinary(data)
 		for i := 1; i < 4; i++ {
 			c.XORKeyStreamAt(dst[:i], src[:i], 0)
-			c.XORKeyStreamAt(dst[32:64], src[32:64], 32)
+			c2.XORKeyStreamAt(dst[32:64], src[32:64], 32)
 			if !bytes.Equal(dst[32:64], expected[32:64]) {
 				t.Errorf("expected=%x, result=%x\n", expected[32:64], dst[32:64])
 			}
@@ -128,8 +132,10 @@ func TestXORStreamAt(t *testing.T) {
 		if !bytes.Equal(dst[3:16], expected[3:16]) {
 			t.Errorf("expected=%x, result=%x\n", expected[3:16], dst[3:16])
 		}
+		data, _ := c.(encoding.BinaryMarshaler).MarshalBinary()
+		c2, _ := UnmarshalEEACipher(data)
 		c.XORKeyStreamAt(dst[:1], src[:1], 0)
-		c.XORKeyStreamAt(dst[4:16], src[4:16], 4)
+		c2.XORKeyStreamAt(dst[4:16], src[4:16], 4)
 		if !bytes.Equal(dst[4:16], expected[4:16]) {
 			t.Errorf("expected=%x, result=%x\n", expected[3:16], dst[3:16])
 		}