feat: 新增XTS/CCM流式与KDF能力，补充安全测试并更新README/CHANGELOG

filex/file.go

@@ -2,10 +2,11 @@ package filex
 
 import (
 	"bufio"
+	crand "crypto/rand"
 	"errors"
 	"fmt"
 	"io"
-	"math/rand"
+	mrand "math/rand"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -15,6 +16,8 @@ import (
 	"time"
 )
 
+var ErrInvalidSplitPattern = errors.New("split dst pattern must contain exactly one '*'")
+
 func Attach(src, dst, output string) error {
 	fpsrc, err := os.Open(src)
 	if err != nil {
@@ -81,6 +84,9 @@ func SplitFile(src, dst string, num int, bynum bool, progress func(float64)) err
 	if num <= 0 {
 		return errors.New("num must be greater than zero")
 	}
+	if strings.Count(dst, "*") != 1 {
+		return ErrInvalidSplitPattern
+	}
 
 	fpsrc, err := os.Open(src)
 	if err != nil {
@@ -244,6 +250,8 @@ func MergeFile(src, dst string, progress func(float64)) error {
 	return nil
 }
 
+// FillWithRandom fills file with pseudo-random bytes generated by math/rand.
+// It is fast but not cryptographically secure.
 func FillWithRandom(path string, filesize, bufcap, bufnum int, progress func(float64)) error {
 	if filesize < 0 {
 		return errors.New("filesize must be non-negative")
@@ -258,7 +266,7 @@ func FillWithRandom(path string, filesize, bufcap, bufnum int, progress func(flo
 		bufcap = filesize
 	}
 
-	rand.Seed(time.Now().UnixNano())
+	r := mrand.New(mrand.NewSource(time.Now().UnixNano()))
 
 	fp, err := os.Create(path)
 	if err != nil {
@@ -267,18 +275,17 @@ func FillWithRandom(path string, filesize, bufcap, bufnum int, progress func(flo
 	defer fp.Close()
 
 	writer := bufio.NewWriter(fp)
-	defer writer.Flush()
 
 	if filesize == 0 {
 		reportProgress(progress, 0, 0)
-		return nil
+		return writer.Flush()
 	}
 
 	pool := make([][]byte, 0, bufnum)
 	for i := 0; i < bufnum; i++ {
 		b := make([]byte, bufcap)
 		for j := 0; j < bufcap; j++ {
-			b[j] = byte(rand.Intn(256))
+			b[j] = byte(r.Intn(256))
 		}
 		pool = append(pool, b)
 	}
@@ -289,14 +296,59 @@ func FillWithRandom(path string, filesize, bufcap, bufnum int, progress func(flo
 		if filesize-written < chunk {
 			chunk = filesize - written
 		}
-		buf := pool[rand.Intn(len(pool))][:chunk]
+		buf := pool[r.Intn(len(pool))][:chunk]
 		if _, err := writer.Write(buf); err != nil {
 			return err
 		}
 		written += chunk
 		reportProgress(progress, int64(written), int64(filesize))
 	}
-	return nil
+	return writer.Flush()
+}
+
+// FillWithCryptoRandom fills file with cryptographically secure random bytes from crypto/rand.
+// Security is stronger than FillWithRandom, but throughput may be lower.
+func FillWithCryptoRandom(path string, filesize, bufcap int, progress func(float64)) error {
+	if filesize < 0 {
+		return errors.New("filesize must be non-negative")
+	}
+	if bufcap <= 0 {
+		bufcap = 1
+	}
+	if bufcap > filesize && filesize > 0 {
+		bufcap = filesize
+	}
+
+	fp, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer fp.Close()
+
+	writer := bufio.NewWriter(fp)
+
+	if filesize == 0 {
+		reportProgress(progress, 0, 0)
+		return writer.Flush()
+	}
+
+	buf := make([]byte, bufcap)
+	written := 0
+	for written < filesize {
+		chunk := bufcap
+		if filesize-written < chunk {
+			chunk = filesize - written
+		}
+		if _, err := io.ReadFull(crand.Reader, buf[:chunk]); err != nil {
+			return err
+		}
+		if _, err := writer.Write(buf[:chunk]); err != nil {
+			return err
+		}
+		written += chunk
+		reportProgress(progress, int64(written), int64(filesize))
+	}
+	return writer.Flush()
 }
 
 func reportProgress(progress func(float64), current, total int64) {

filex/file_random_test.go

@@ -0,0 +1,65 @@
+package filex
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestFillWithRandomAndCryptoRandom(t *testing.T) {
+	dir := t.TempDir()
+	pseudoPath := filepath.Join(dir, "pseudo.bin")
+	securePath := filepath.Join(dir, "secure.bin")
+
+	if err := FillWithRandom(pseudoPath, 2048, 128, 4, nil); err != nil {
+		t.Fatalf("FillWithRandom failed: %v", err)
+	}
+	if err := FillWithCryptoRandom(securePath, 2048, 128, nil); err != nil {
+		t.Fatalf("FillWithCryptoRandom failed: %v", err)
+	}
+
+	pseudoInfo, err := os.Stat(pseudoPath)
+	if err != nil {
+		t.Fatalf("stat pseudo file failed: %v", err)
+	}
+	if pseudoInfo.Size() != 2048 {
+		t.Fatalf("unexpected pseudo size: %d", pseudoInfo.Size())
+	}
+
+	secureInfo, err := os.Stat(securePath)
+	if err != nil {
+		t.Fatalf("stat secure file failed: %v", err)
+	}
+	if secureInfo.Size() != 2048 {
+		t.Fatalf("unexpected secure size: %d", secureInfo.Size())
+	}
+
+	pseudo, err := os.ReadFile(pseudoPath)
+	if err != nil {
+		t.Fatalf("read pseudo file failed: %v", err)
+	}
+	secure, err := os.ReadFile(securePath)
+	if err != nil {
+		t.Fatalf("read secure file failed: %v", err)
+	}
+
+	if bytes.Equal(secure, make([]byte, len(secure))) {
+		t.Fatalf("secure random output should not be all zero")
+	}
+	if bytes.Equal(pseudo, secure) {
+		t.Fatalf("pseudo and secure random outputs unexpectedly identical")
+	}
+}
+
+func TestFillWithRandomInvalidArgs(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "bad.bin")
+
+	if err := FillWithRandom(path, -1, 16, 1, nil); err == nil {
+		t.Fatalf("expected FillWithRandom negative filesize error")
+	}
+	if err := FillWithCryptoRandom(path, -1, 16, nil); err == nil {
+		t.Fatalf("expected FillWithCryptoRandom negative filesize error")
+	}
+}

filex/file_split_test.go

@@ -0,0 +1,36 @@
+package filex
+
+import (
+	"bytes"
+	"errors"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestSplitFilePatternValidation(t *testing.T) {
+	dir := t.TempDir()
+	src := filepath.Join(dir, "src.bin")
+	if err := os.WriteFile(src, bytes.Repeat([]byte{0x7f}, 64), 0o600); err != nil {
+		t.Fatalf("WriteFile failed: %v", err)
+	}
+
+	if err := SplitFile(src, filepath.Join(dir, "part.bin"), 2, true, nil); !errors.Is(err, ErrInvalidSplitPattern) {
+		t.Fatalf("expected ErrInvalidSplitPattern for missing '*', got: %v", err)
+	}
+	if err := SplitFile(src, filepath.Join(dir, "part_*_*.bin"), 2, true, nil); !errors.Is(err, ErrInvalidSplitPattern) {
+		t.Fatalf("expected ErrInvalidSplitPattern for multiple '*', got: %v", err)
+	}
+
+	pattern := filepath.Join(dir, "part_*.bin")
+	if err := SplitFile(src, pattern, 2, true, nil); err != nil {
+		t.Fatalf("SplitFile valid pattern failed: %v", err)
+	}
+
+	if _, err := os.Stat(filepath.Join(dir, "part_0.bin")); err != nil {
+		t.Fatalf("part_0.bin not found: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(dir, "part_1.bin")); err != nil {
+		t.Fatalf("part_1.bin not found: %v", err)
+	}
+}