Playing around

crypto.go

@@ -443,6 +443,12 @@ func (h *FileHeader) SetPassword(password string) {
 	}
 }
 
+func (h *FileHeader) SetDecryptionPassword(password string) {
+	h.password = func() []byte {
+		return []byte(password)
+	}
+}
+
 // PasswordFn is a function that returns the password
 // as a byte slice
 type passwordFn func() []byte
@@ -457,6 +463,6 @@ func (w *Writer) Encrypt(name string, password string) (io.Writer, error) {
 		Name:   name,
 		Method: Deflate,
 	}
-	fh.SetPassword(password)
+	fh.SetDecryptionPassword(password)
 	return w.CreateHeader(fh)
 }

reader.go

@@ -143,14 +143,21 @@ func (f *File) Open() (rc io.ReadCloser, err error) {
 	size := int64(f.CompressedSize64)
 	var r io.Reader
 	rr := io.NewSectionReader(f.zipr, f.headerOffset+bodyOffset, size)
+
 	// check for encryption
 	if f.IsEncrypted() {
-		if r, err = newDecryptionReader(rr, f); err != nil {
+		if f.ae == 0 {
+			fmt.Printf("CRC32: %X ---- %v\n", f.CRC32, f.CRC32)
+			if r, err = ZipCryptoDecryptor(rr, f.password()); err != nil {
+				return
+			}
+		} else if r, err = newDecryptionReader(rr, f); err != nil {
 			return
 		}
 	} else {
 		r = rr
 	}
+
 	dcomp := decompressor(f.Method)
 	if dcomp == nil {
 		err = ErrAlgorithm
@@ -254,14 +261,21 @@ func readDirectoryHeader(f *File, r io.Reader) error {
 	f.CreatorVersion = b.uint16()
 	f.ReaderVersion = b.uint16()
 	f.Flags = b.uint16()
+	fmt.Printf("FLAG: %X\n", f.Flags)
 	f.Method = b.uint16()
+	fmt.Printf("METHOD: %X\n", f.Method)
 	f.ModifiedTime = b.uint16()
 	f.ModifiedDate = b.uint16()
 	f.CRC32 = b.uint32()
+	fmt.Printf("Directory CRC: %X\n", f.CRC32)
 	f.CompressedSize = b.uint32()
 	f.UncompressedSize = b.uint32()
 	f.CompressedSize64 = uint64(f.CompressedSize)
 	f.UncompressedSize64 = uint64(f.UncompressedSize)
+	fmt.Printf("ZIP Size 1: %v\n", f.CompressedSize)
+	fmt.Printf("ZIP Size 2: %v\n", f.CompressedSize64)
+	fmt.Printf("File Size 1: %v\n", f.UncompressedSize)
+	fmt.Printf("File Size 2: %v\n", f.UncompressedSize64)
 	filenameLen := int(b.uint16())
 	extraLen := int(b.uint16())
 	commentLen := int(b.uint16())

temp/int.go

@@ -0,0 +1,32 @@
+package main
+
+import "fmt"
+
+type Int int
+
+func (i *Int) Incr(n int) Int {
+	*i = (*i) + Int(n)
+	return *i
+}
+
+
+func main() {
+	i := Int(10)
+	i.Incr(12)
+	fmt.Println(i)
+
+	b := &Bytes{b: []byte{1, 2, 3, 4, 5}, i: 0}
+	c := b.Get(0, 3)
+	c[1] = 11
+	fmt.Println(b)
+	fmt.Println(c)
+
+	j := &Bytes{b: []byte{1, 2, 3, 4, 5}, i: 0}
+	k := j.IGet(3)
+	l := j.IGet(2)
+	k[0] = 10
+	l[0] = 11
+	fmt.Println(j)
+	fmt.Println(k)
+	fmt.Println(l)
+}

temp/play.go

@@ -0,0 +1,544 @@
+package main
+
+import (
+	zip2 "github.com/yeka/zip"
+	"bytes"
+	"os"
+	"io"
+	"fmt"
+	"archive/zip"
+	"log"
+	"hash/crc32"
+	"encoding/binary"
+	"io/ioutil"
+)
+
+func main() {
+	//fmt.Printf("%X\n", crc32.Update(0, crc32.IEEETable, []byte{0}))
+	//return
+
+	password := "zipcrypto"
+	new(ZipReader).FromBytes(createzip(password), password)
+	new(ZipReader).Open("java2.zip", password) // FA176C7F
+
+	os.Remove("myzip/test1.zip")
+	ioutil.WriteFile("myzip/test1.zip", createzip(password), os.ModePerm)
+	return
+	//z.Open("java2.zip", "zipcrypto") // FA176C7F
+	//z.Open("java.zip", "123")
+
+	//z.Open("a.zip")
+	//z.Open("test.zip")
+	fmt.Println("=======================================")
+	return
+	//unknown1()
+	//show("java.zip", "zipcrypto")
+	zipunzip()
+	return
+	fmt.Printf("%X\n", 878082192)
+	show("banyak.zip", "123")
+	//show("pass.zip", "zipcrypto")
+	//show("java.zip", "zipcrypto")
+	//show("a.zip", "aa") // Incorrect password
+	//show("test.zip", "")
+
+	fmt.Printf("%b\n", zip2.Crc32update(0, 0))
+	h := crc32.NewIEEE()
+	h.Write([]byte{0})
+	fmt.Printf("%b\n", h.Sum32())
+	fmt.Printf("%b\n", crc32.Update(0, crc32.IEEETable, []byte{0}))
+
+}
+
+func play1() {
+	de := []byte("hello")
+	//e := zip.NewZipCrypto([]byte("Passwordnya panjang banget kk"))
+	//en := e.EncryptMessage([]byte("Hello Worlds Muahaha"))
+	//d := zip.NewZipCrypto([]byte("Passwordnya panjang banget kk"))
+	//de = d.DecryptMessage(en)
+	fmt.Println(string(de))
+
+	os.Exit(0)
+	buf := new(bytes.Buffer)
+	//a := zip.NewWriter(buf)
+	//w, _ := a.Create("a.txt")
+	//w.Write([]byte(`Hello World`))
+	//a.Close()
+
+	f, _ := os.Create("temp/test.zip")
+	io.Copy(f, buf)
+	f.Close()
+
+	_ = zip.Deflate
+}
+
+func show(filename string, password string) {
+	r, err := zip2.OpenReader(filename)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer r.Close()
+
+	for _, f := range r.File {
+		fmt.Printf("------ %s ------\n", f.Name)
+
+		f.SetDecryptionPassword(password)
+		rc, err := f.Open()
+		if err != nil {
+			fmt.Println("Opening error")
+			log.Print(err)
+			continue
+		}
+		buf := new(bytes.Buffer)
+		if _, err = io.Copy(buf, rc); err != nil {
+			fmt.Println("buffering error")
+			log.Print(err)
+			continue
+		}
+
+		fmt.Printf("Size: %d\nContent:\n", buf.Len())
+		fmt.Println(string(buf.Bytes()))
+		//fmt.Println(buf.Bytes())
+		rc.Close()
+		fmt.Println()
+		fmt.Println()
+	}
+}
+
+func createzip(password string) []byte {
+	fmt.Printf("\n\n========================== Writing ========================== \n\n")
+	mydata, _ := ioutil.ReadFile("a.java")
+	b := new(bytes.Buffer)
+	z := zip2.NewWriter(b)
+	//w, _ := z.Create("a.java")
+	w, _ := z.Encrypt("a.java", password)
+	fmt.Println(w.Write(mydata))
+	z.Close()
+	return b.Bytes()
+}
+
+func zipunzip() {
+	fmt.Printf("\n\n========================== Writing ========================== \n\n")
+	mydata := []byte(`Hello World`)
+	password := "golang"
+	b := new(bytes.Buffer)
+	z := zip2.NewWriter(b)
+	//w, _ := z.Create("a.txt")
+	w, _ := z.Encrypt("a.txt", password)
+	fmt.Println(w.Write(mydata))
+	z.Close()
+
+	fmt.Printf("\n\n========================== Reading ========================== \n\n")
+	rz, _ := zip2.NewReader(bytes.NewReader(b.Bytes()), int64(b.Len()))
+	rz.File[0].SetDecryptionPassword(password)
+	r, _ := rz.File[0].Open()
+	myresult := new(bytes.Buffer)
+	io.Copy(myresult, r)
+	r.Close()
+
+	fmt.Println(mydata)
+	fmt.Println(myresult.Bytes())
+	fmt.Println(0 == bytes.Compare(mydata, myresult.Bytes()))
+}
+
+func unknown1() {
+	hello := []byte("Hello world\n")
+	b := new(bytes.Buffer)
+
+	l := &zipwriterboongan{b}
+	c := &zipwriterboongan{l}
+	//m := &minues{l}
+	//c := &minues2{m}
+	//
+	////i := io.MultiWriter(b, m, l, c)
+	//c.Write(hello)
+	c.Write(hello)
+	fmt.Println(string(b.Bytes()))
+}
+
+type zipwriterboongan struct {
+	w io.Writer
+}
+
+func (m *zipwriterboongan) Write(p []byte) (i int, err error) {
+	temp := make([]byte, len(p))
+	for i, b := range p {
+		temp[i] = b ^ 0xFF
+	}
+	m.w.Write(temp)
+	return
+}
+
+type ftpwriterboongan struct {
+	w io.Writer
+}
+
+func (m *ftpwriterboongan) Write(p []byte) (i int, err error) {
+	temp := make([]byte, len(p))
+	for i, b := range p {
+		temp[i] = b ^ 0xFF
+	}
+	m.w.Write(temp)
+	return
+}
+
+type ZipReader struct {
+	b           *Bytes
+	password    []byte
+	files       []*ZipFile
+	central_dir []*ZipCentralDirectory
+	dir_end     *ZipDirectoryEnd
+}
+
+type ZipFile struct {
+	zip        *ZipReader
+	header     *ZipFileHeader
+	data       *ZipFileData
+	descriptor *ZipFileDescriptor
+}
+
+func (zf *ZipFile) init(offset, datasize uint64) {
+	h := &ZipFileHeader{file: zf}
+	h.init(offset)
+
+	f := &ZipFileData{file: zf}
+	f.content = zf.zip.b.IGet(datasize)
+
+	e := &ZipFileDescriptor{file: zf}
+	if u16x(h.general_purpose_bit_flag) & 8 > 0 {
+		e.init(zf.zip.b.Pos())
+	}
+
+	zf.header = h
+	zf.data = f
+	zf.descriptor = e
+}
+
+type ZipFileHeader struct {
+	file *ZipFile
+	local_file_header_signature []byte
+	version_needed_to_extract   []byte
+	general_purpose_bit_flag    []byte
+	compression_method          []byte
+	last_mod_file_time          []byte
+	last_mod_file_date          []byte
+	crc_32                      []byte
+	compressed_size             []byte
+	uncompressed_size           []byte
+	filename_length             []byte
+	extra_field_length          []byte
+	filename                    []byte
+	extra_field                 []byte
+}
+
+func (fh *ZipFileHeader) init(offset uint64)  {
+	b := fh.file.zip.b
+	b.Offset(offset)
+	fh.local_file_header_signature = b.IGet(4)
+	fh.version_needed_to_extract   = b.IGet(2)
+	fh.general_purpose_bit_flag    = b.IGet(2)
+	fh.compression_method          = b.IGet(2)
+	fh.last_mod_file_time          = b.IGet(2)
+	fh.last_mod_file_date          = b.IGet(2)
+	fh.crc_32                      = b.IGet(4)
+	fh.compressed_size             = b.IGet(4)
+	fh.uncompressed_size           = b.IGet(4)
+	fh.filename_length             = b.IGet(2)
+	fh.extra_field_length          = b.IGet(2)
+	fh.filename                    = b.IGet(u16x(fh.filename_length))
+	fh.extra_field                 = b.IGet(u16x(fh.extra_field_length))
+}
+
+type ZipFileData struct {
+	file *ZipFile
+	content []byte
+}
+
+type ZipFileDescriptor struct {
+	file *ZipFile
+	signature         []byte
+	crc_32            []byte
+	compressed_size   []byte
+	uncompressed_size []byte
+}
+
+func (fd *ZipFileDescriptor) init(offset uint64)  {
+	b := fd.file.zip.b
+	b.Offset(offset)
+	sig := b.IGet(4)
+	if u32x(sig) == 0x08074b50 {
+		fd.signature = sig
+		fd.crc_32 = b.IGet(4)
+	} else {
+		fd.crc_32 = sig
+	}
+	fd.compressed_size = b.IGet(4)
+	fd.uncompressed_size = b.IGet(4)
+}
+
+type ZipCentralDirectory struct {
+	zip *ZipReader
+	central_file_header_signature []byte
+	version_made_by               []byte
+	version_needed_to_extrac      []byte
+	general_purpose_bit_flag      []byte
+	compression_method            []byte
+	last_mod_file_time            []byte
+	last_mod_file_date            []byte
+	crc_32                        []byte
+	compressed_size               []byte
+	uncompressed_size             []byte
+	filename_length               []byte
+	extra_field_length            []byte
+	file_comment_length           []byte
+	disk_num_start                []byte
+	internal_file_attr            []byte
+	external_file_attr            []byte
+	local_header_relative_offset  []byte
+	filename                      []byte
+	extra_field                   []byte
+	file_comment                  []byte
+}
+
+func (cd *ZipCentralDirectory) init(offset uint64) (size uint64) {
+	cd.zip.b.Offset(offset)
+	cd.central_file_header_signature = cd.zip.b.IGet(4)
+	cd.version_made_by               = cd.zip.b.IGet(2)
+	cd.version_needed_to_extrac      = cd.zip.b.IGet(2)
+	cd.general_purpose_bit_flag      = cd.zip.b.IGet(2)
+	cd.compression_method            = cd.zip.b.IGet(2)
+	cd.last_mod_file_time            = cd.zip.b.IGet(2)
+	cd.last_mod_file_date            = cd.zip.b.IGet(2)
+	cd.crc_32                        = cd.zip.b.IGet(4)
+	cd.compressed_size               = cd.zip.b.IGet(4)
+	cd.uncompressed_size             = cd.zip.b.IGet(4)
+	cd.filename_length               = cd.zip.b.IGet(2)
+	cd.extra_field_length            = cd.zip.b.IGet(2)
+	cd.file_comment_length           = cd.zip.b.IGet(2)
+	cd.disk_num_start                = cd.zip.b.IGet(2)
+	cd.internal_file_attr            = cd.zip.b.IGet(2)
+	cd.external_file_attr            = cd.zip.b.IGet(4)
+	cd.local_header_relative_offset  = cd.zip.b.IGet(4)
+	cd.filename                      = cd.zip.b.IGet(u16x(cd.filename_length))
+	cd.extra_field                   = cd.zip.b.IGet(u16x(cd.extra_field_length))
+	cd.file_comment                  = cd.zip.b.IGet(u16x(cd.file_comment_length))
+	size = 46 + u16x(cd.filename_length) + u16x(cd.extra_field_length) + u16x(cd.file_comment_length)
+	return
+}
+
+type ZipDirectoryEnd struct {
+	zip *ZipReader
+	signature                          []byte
+	disknum                            []byte
+	disknum_start_of_central_directory []byte
+	entries_in_this_disk               []byte
+	num_of_entries                     []byte
+	size_of_central_dir                []byte
+	offset_of_central_dir              []byte
+	zipfile_comment_length             []byte
+	zipfile_comment                    []byte
+}
+
+func (zde *ZipDirectoryEnd) init(offset uint64) {
+	zde.zip.b.Offset(offset)
+	zde.signature                          = zde.zip.b.IGet(4)
+	zde.disknum                            = zde.zip.b.IGet(2)
+	zde.disknum_start_of_central_directory = zde.zip.b.IGet(2)
+	zde.entries_in_this_disk               = zde.zip.b.IGet(2)
+	zde.num_of_entries                     = zde.zip.b.IGet(2)
+	zde.size_of_central_dir                = zde.zip.b.IGet(4)
+	zde.offset_of_central_dir              = zde.zip.b.IGet(4)
+	zde.zipfile_comment_length             = zde.zip.b.IGet(2)
+	zde.zipfile_comment                    = zde.zip.b.IGet(u16x(zde.zipfile_comment_length))
+}
+
+func (z *ZipReader) FromBytes(buf []byte, password string) {
+	z.b = &Bytes{buf, 0}
+	z.password = []byte(password)
+	z.Init()
+}
+
+func (z *ZipReader) Open(filename string, password string) {
+	buf, _ := ioutil.ReadFile(filename)
+	z.FromBytes(buf, password)
+}
+
+func (z *ZipReader) Init() {
+	// First find Directory End
+	var i uint64
+	for i = uint64(len(z.b.b)) - 22; i >= 0; i-- {
+		if z.b.BGet(i, 4).I64() == 0x06054b50 {
+			z.dir_end = &ZipDirectoryEnd{zip: z}
+			z.dir_end.init(i)
+			break
+		}
+	}
+
+	// Read all Central Directory Header
+	central_dir_offset := u16x(z.dir_end.offset_of_central_dir)
+	for i = 0; i < u16x(z.dir_end.num_of_entries); i++ {
+		cdfh := &ZipCentralDirectory{zip: z}
+		central_dir_offset += cdfh.init(central_dir_offset)
+		z.central_dir = append(z.central_dir, cdfh)
+	}
+
+	for i = 0; i < u16x(z.dir_end.num_of_entries); i++ {
+		zf := &ZipFile{zip: z}
+		zf.init(u32x(z.central_dir[i].local_header_relative_offset), u32x(z.central_dir[i].compressed_size))
+		z.files = append(z.files, zf)
+	}
+
+	fmt.Printf("%0 X\n", z.files[0].header)
+	fmt.Printf("%0 X\n", z.files[0].descriptor)
+	// PlayGround
+	//fmt.Printf("%v\n", z.files[0].data.content)
+	//zc := zip2.NewZipCrypto(z.password)
+	//buf := zc.DecryptMessage(z.files[0].data.content)
+	////fmt.Printf("%v\n", buf)
+	//rc := flate.NewReader(bytes.NewBuffer(buf[12:]))
+	//defer rc.Close()
+	//res, err := ioutil.ReadAll(rc)
+	//if err != nil {
+	//	fmt.Println(err.Error())
+	//}
+	//fmt.Printf("%v\n", string(res))
+
+	//fmt.Printf("---------------- %v ----------------\n", string(h.filename))
+		//fmt.Printf("Signature: %02X\n", h.local_file_header_signature)
+		//fmt.Printf("Version: %v\n", h.version_needed_to_extract)
+		//fmt.Printf("General Purpose Bit Flag: %08b\n", h.general_purpose_bit_flag)
+		//fmt.Printf("Compression Method: %v\n", h.compression_method)
+		//fmt.Printf("CRC32: %0 X, Compressed: %v, Uncompressed: %v\n", h.crc_32, u16x(h.compressed_size), u16x(h.uncompressed_size))
+		//fmt.Printf("FileName Length: %v\n", u16x(h.filename_length))
+		//fmt.Printf("ExtraField Length: %v\n", u16x(h.extra_field_length))
+		//fmt.Printf("ExtraField: %0 X\n", h.extra_field)
+		//if u16x(h.general_purpose_bit_flag) & 8 > 0 {
+		//	crc32 := z.b.IGet(4)
+		//	if u32x(crc32) == 0x08074b50 {
+		//		// Signature may or may not be there
+		//		crc32 = z.b.IGet(4)
+		//	}
+		//	csize := z.b.IGet(4)
+		//	usize := z.b.IGet(4)
+		//	fmt.Printf("DataDescriptor:\nCRC32: %0 X, Compressed: %v, Uncompressed: %v, Next Signature: %X\n", crc32, u16x(csize), u16x(usize), z.b.IGet(4))
+		//}
+		//
+		//crcbuf := make([]byte, 4)
+		//crcbuf[3] = h.crc_32[3]
+		//crcbuf[2] = (h.crc_32[3] >> 8)
+		//crcbuf[1] = (h.crc_32[3] >> 16)
+		//crcbuf[0] = (h.crc_32[3] >> 24)
+		//
+		////fmt.Printf("CRC BUF: %x %v\n", crcbuf, crcbuf)
+		//
+		////fmt.Printf("% X\n", file_data)
+		//if u16x(h.general_purpose_bit_flag) & 1 > 0 {
+		//	fmt.Println("Encrypted")
+		//	zc := zip2.NewZipCrypto(z.password)
+		//
+		//	//result := file_data[0]
+		//	//for i := 0; i < 12; i++ {
+		//	//	if i == 11 {
+		//	//		//fmt.Printf("HASH MAGIC: %X %v\n", result ^ zc.MagicByte(), result ^ zc.MagicByte())
+		//	//	}
+		//	//	zc.UpdateKeys(result ^ zc.MagicByte())
+		//	//	if i < 12 {
+		//	//		result = file_data[i + 1]
+		//	//	}
+		//	//}
+		//	file_header := zc.DecryptMessage(file_data[0:12])
+		//	//fmt.Printf("Magic Byte: %X\n", zc.MagicByte())
+		//	file_data = zc.DecryptMessage(file_data[12:])
+		//	fmt.Printf("%0 X : %0 X\n", file_header, file_data)
+		//	//fmt.Printf("%v %v\n", string(file_data[0:12]), string(file_data[12:]))
+		//	//file_data = file_data[12:]
+		//}
+		//if u16x(h.compression_method) == 8 {
+		//	//fmt.Printf("Compressed: %v\n", len(file_data))
+		//	rc := flate.NewReader(bytes.NewBuffer(file_data))
+		//	defer rc.Close()
+		//	res, err := ioutil.ReadAll(rc)
+		//	file_data = res
+		//	if err != nil {
+		//		fmt.Println(err.Error())
+		//	}
+		//}
+		//crc := crc32.NewIEEE()
+		//crc.Write(file_data)
+		//fmt.Printf("GO CRC: %X\n", crc.Sum32())
+		//fmt.Printf("\n%v\n", string(file_data))
+	//}
+}
+
+func (z *ZipReader) DirectoryStructure() {
+
+}
+
+func u16(b []byte) uint16 {
+	return binary.LittleEndian.Uint16(b)
+}
+
+func u32(b []byte) uint32 {
+	return binary.LittleEndian.Uint32(b)
+}
+
+func u16x(b []byte) uint64 {
+	return uint64(u16(b))
+}
+
+func u32x(b []byte) uint64 {
+	return uint64(u32(b))
+}
+
+func u64x(b []byte) uint64 {
+	return uint64(u32(b))
+}
+
+
+type Bytes struct {
+	b []byte
+	i uint64
+}
+
+// Get slice of byte
+func (b *Bytes) Get(offset, size uint64) []byte {
+	return b.b[offset : offset + size]
+}
+
+func (b *Bytes) BGet(offset, size uint64) *Bytes {
+	return &Bytes{b.Get(offset, size), 0}
+}
+
+// Incremental Get
+func (b *Bytes) IGet(size uint64) []byte {
+	i := b.i
+	b.i = i + size
+	return b.b[i : b.i]
+}
+
+// Incremental Get
+func (b *Bytes) IBGet(size uint64) *Bytes {
+	return &Bytes{b.IGet(size), 0}
+}
+
+func (b *Bytes) I64() uint64 {
+	switch len(b.b) {
+	case 1:
+		return uint64(b.b[0])
+	case 2:
+		return u16x(b.b)
+	case 4:
+		return u32x(b.b)
+	case 8:
+		return u64x(b.b)
+	}
+	return 0
+}
+// Set offset
+func (b *Bytes) Offset(i uint64) {
+	b.i = i
+}
+
+func (b *Bytes) Pos() uint64 {
+	return b.i
+}

writer.go

@@ -11,10 +11,10 @@ import (
 	"hash"
 	"hash/crc32"
 	"io"
+	"fmt"
 )
 
 // TODO(adg): support zip file comments
-// TODO(adg): support specifying deflate level
 
 // Writer implements a zip file writer.
 type Writer struct {
@@ -22,6 +22,7 @@ type Writer struct {
 	dir         []*header
 	last        *fileWriter
 	closed      bool
+	compressors map[uint16]Compressor
 }
 
 type header struct {
@@ -52,7 +53,7 @@ func (w *Writer) Flush() error {
 }
 
 // Close finishes writing the zip file by writing the central directory.
-// It does not (and can not) close the underlying writer.
+// It does not (and cannot) close the underlying writer.
 func (w *Writer) Close() error {
 	if w.last != nil && !w.last.closed {
 		if err := w.last.close(); err != nil {
@@ -78,7 +79,8 @@ func (w *Writer) Close() error {
 		b.uint16(h.ModifiedTime)
 		b.uint16(h.ModifiedDate)
 		b.uint32(h.CRC32)
-		if h.isZip64() || h.offset > uint32max {
+
+		if h.isZip64() || h.offset >= uint32max {
 			// the file needs a zip64 header. store maxint in both
 			// 32 bit size fields (and offset later) to signal that the
 			// zip64 extra header should be used.
@@ -98,6 +100,7 @@ func (w *Writer) Close() error {
 			b.uint32(h.CompressedSize)
 			b.uint32(h.UncompressedSize)
 		}
+
 		b.uint16(uint16(len(h.Name)))
 		b.uint16(uint16(len(h.Extra)))
 		b.uint16(uint16(len(h.Comment)))
@@ -211,8 +214,7 @@ func (w *Writer) CreateHeader(fh *FileHeader) (io.Writer, error) {
 	}
 
 	fh.Flags |= 0x8 // we will write a data descriptor
-	// TODO(alex): Look at spec and see if these need to be changed
+
-	// when using encryption.
 	fh.CreatorVersion = fh.CreatorVersion&0xff00 | zipVersion20 // preserve compatibility byte
 	fh.ReaderVersion = zipVersion20
 
@@ -221,18 +223,17 @@ func (w *Writer) CreateHeader(fh *FileHeader) (io.Writer, error) {
 		compCount: &countWriter{w: w.cw},
 		crc32:     crc32.NewIEEE(),
 	}
-	// Get the compressor before possibly changing Method to 99 due to password
+	comp := w.compressor(fh.Method)
-	comp := compressor(fh.Method)
 	if comp == nil {
 		return nil, ErrAlgorithm
 	}
 	// check for password
 	var sw io.Writer = fw.compCount
 	if fh.password != nil {
-		// we have a password and need to encrypt.
+		if !fh.IsEncrypted() {
-		fh.writeWinZipExtra()
+			fh.setEncryptionBit()
-		fh.Method = 99 // ok to change, we've gotten the comp and wrote extra
+		}
-		ew, err := newEncryptionWriter(sw, fh.password, fw)
+		ew, err := ZipCryptoEncryptor(sw, fh.password, fw)
 		if err != nil {
 			return nil, err
 		}
@@ -272,6 +273,7 @@ func writeHeader(w io.Writer, h *FileHeader) error {
 	b.uint32(0) // since we are writing a data descriptor crc32,
 	b.uint32(0) // compressed size,
 	b.uint32(0) // and uncompressed size should be zero
+	fmt.Printf("File HEader Wring %0 X, %v, %v\n", h.CRC32, h.CompressedSize, h.UncompressedSize)
 	b.uint16(uint16(len(h.Name)))
 	b.uint16(uint16(len(h.Extra)))
 	if _, err := w.Write(buf[:]); err != nil {
@@ -284,6 +286,24 @@ func writeHeader(w io.Writer, h *FileHeader) error {
 	return err
 }
 
+// RegisterCompressor registers or overrides a custom compressor for a specific
+// method ID. If a compressor for a given method is not found, Writer will
+// default to looking up the compressor at the package level.
+func (w *Writer) RegisterCompressor(method uint16, comp Compressor) {
+	if w.compressors == nil {
+		w.compressors = make(map[uint16]Compressor)
+	}
+	w.compressors[method] = comp
+}
+
+func (w *Writer) compressor(method uint16) Compressor {
+	comp := w.compressors[method]
+	if comp == nil {
+		comp = compressor(method)
+	}
+	return comp
+}
+
 type fileWriter struct {
 	*header
 	zipw      io.Writer
@@ -312,21 +332,10 @@ func (w *fileWriter) close() error {
 	if err := w.comp.Close(); err != nil {
 		return err
 	}
-	// if encrypted grab the hmac and write it out
+
-	if w.header.IsEncrypted() {
-		authCode := w.hmac.Sum(nil)
-		authCode = authCode[:10]
-		_, err := w.compCount.Write(authCode)
-		if err != nil {
-			return errors.New("zip: error writing authcode")
-		}
-	}
 	// update FileHeader
 	fh := w.header.FileHeader
-	// ae-2 we don't write out CRC
-	if !fh.IsEncrypted() {
 	fh.CRC32 = w.crc32.Sum32()
-	}
 	fh.CompressedSize64 = uint64(w.compCount.count)
 	fh.UncompressedSize64 = uint64(w.rawCount.count)
 

zipcrypto.go

@@ -0,0 +1,121 @@
+package zip
+
+import (
+	"io"
+	"bytes"
+	"fmt"
+	"hash/crc32"
+)
+
+type ZipCrypto struct {
+	password []byte
+	Keys [3]uint32
+}
+
+func NewZipCrypto(passphrase []byte) *ZipCrypto {
+	z := &ZipCrypto{}
+	z.password = passphrase
+	z.Init()
+	return z
+}
+
+func (z *ZipCrypto) Init() {
+	z.Keys[0] = 0x12345678
+	z.Keys[1] = 0x23456789
+	z.Keys[2] = 0x34567890
+
+	for i := 0; i < len(z.password); i++ {
+		z.UpdateKeys(z.password[i])
+	}
+}
+
+func (z *ZipCrypto) UpdateKeys(byteValue byte) {
+	z.Keys[0] = Crc32update(z.Keys[0], byteValue);
+	z.Keys[1] += z.Keys[0] & 0xff;
+	z.Keys[1] = z.Keys[1] * 134775813 + 1;
+	z.Keys[2] = Crc32update(z.Keys[2], (byte) (z.Keys[1] >> 24));
+}
+
+func (z *ZipCrypto) MagicByte() byte {
+	var t uint32 = z.Keys[2] | 2
+	return byte((t * (t ^ 1)) >> 8)
+}
+
+func (z *ZipCrypto) EncryptMessage(plaintext []byte) []byte {
+	length := len(plaintext)
+	CipherText := make([]byte, length)
+	for i := 0; i < length; i++ {
+		C := plaintext[i]
+		CipherText[i] = plaintext[i] ^ z.MagicByte()
+		z.UpdateKeys(C)
+	}
+	return CipherText
+}
+
+func (z *ZipCrypto) DecryptMessage(chipertext []byte) []byte {
+	length := len(chipertext)
+	PlainText := make([]byte, length)
+	for i, c := range chipertext {
+		v := c ^ z.MagicByte();
+		z.UpdateKeys(v)
+		PlainText[i] = v
+	}
+	return PlainText
+}
+
+func Crc32update(pCrc32 uint32, bval byte) uint32 {
+	return crc32.IEEETable[(pCrc32 ^ uint32(bval)) & 0xff] ^ (pCrc32 >> 8)
+}
+
+func ZipCryptoDecryptor(r *io.SectionReader, password []byte) (*io.SectionReader, error) {
+	//return r, nil
+	z := NewZipCrypto(password)
+	b := make([]byte, r.Size())
+
+	r.Read(b)
+
+	m := z.DecryptMessage(b)
+	fmt.Printf("Header: %X %X %X\n%v\n", m[0:4], m[4:8], m[8:12], m[0:12])
+	fmt.Printf("Header: %X\n", m[11])
+	fmt.Printf("Content: %X\n", m[12:])
+	fmt.Printf("Content: %v\n", string(m[12:]))
+	//if m[11] > 0xFF {
+	//	return nil, errors.New("incorrect password")
+	//}
+	//fmt.Printf("Size: %v\n", len(m))
+	return io.NewSectionReader(bytes.NewReader(m), 12, int64(len(m))), nil
+}
+
+type zipCryptoWriter struct {
+	w     io.Writer
+	z     *ZipCrypto
+	first bool
+	fw    *fileWriter
+}
+
+func (z *zipCryptoWriter) Write(p []byte) (n int, err error) {
+	if z.first {
+		z.first = false
+		header := []byte{0xF8, 0x53, 0xCF, 0x05, 0x2D, 0xDD, 0xAD, 0xC8, 0x66, 0x3F, 0x8C, 0xAC}
+		header = z.z.EncryptMessage(header)
+
+		crc := z.fw.ModifiedTime
+		header[10] = byte(crc)
+		header[11] = byte(crc >> 8)
+
+		z.z.Init()
+		z.w.Write(z.z.EncryptMessage(header))
+		n += 12
+		//z.z.Init()
+	}
+	z.w.Write(z.z.EncryptMessage(p))
+	z.fw.FileHeader.CompressedSize += uint32(n)
+	return
+}
+
+func ZipCryptoEncryptor(i io.Writer, pass passwordFn, fw *fileWriter) (io.Writer, error)  {
+	fmt.Printf("Initializationg...\n")
+	z := NewZipCrypto(pass())
+	zc := &zipCryptoWriter{i, z, true, fw}
+	return zc, nil
+}