mirror of
https://github.com/nadoo/glider.git
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297 lines
7.9 KiB
Go
297 lines
7.9 KiB
Go
package shadowsocksr
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/des"
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"crypto/md5"
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"crypto/rand"
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"crypto/rc4"
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"encoding/binary"
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"errors"
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"github.com/sun8911879/shadowsocksR/tools"
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"github.com/sun8911879/shadowsocksR/tools/leakybuf"
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"github.com/Yawning/chacha20"
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"github.com/dgryski/go-camellia"
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"github.com/dgryski/go-idea"
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"github.com/dgryski/go-rc2"
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"golang.org/x/crypto/blowfish"
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"golang.org/x/crypto/cast5"
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"golang.org/x/crypto/salsa20/salsa"
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)
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var errEmptyPassword = errors.New("empty key")
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type DecOrEnc int
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const (
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Decrypt DecOrEnc = iota
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Encrypt
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)
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func newCTRStream(block cipher.Block, err error, key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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if err != nil {
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return nil, err
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}
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return cipher.NewCTR(block, iv), nil
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}
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func newAESCTRStream(key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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block, err := aes.NewCipher(key)
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return newCTRStream(block, err, key, iv, doe)
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}
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func newOFBStream(block cipher.Block, err error, key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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if err != nil {
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return nil, err
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}
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return cipher.NewCTR(block, iv), nil
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}
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func newAESOFBStream(key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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block, err := aes.NewCipher(key)
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return newOFBStream(block, err, key, iv, doe)
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}
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func newCFBStream(block cipher.Block, err error, key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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if err != nil {
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return nil, err
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}
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if doe == Encrypt {
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return cipher.NewCFBEncrypter(block, iv), nil
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} else {
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return cipher.NewCFBDecrypter(block, iv), nil
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}
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}
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func newAESCFBStream(key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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block, err := aes.NewCipher(key)
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return newCFBStream(block, err, key, iv, doe)
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}
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func newDESStream(key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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block, err := des.NewCipher(key)
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return newCFBStream(block, err, key, iv, doe)
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}
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func newBlowFishStream(key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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block, err := blowfish.NewCipher(key)
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return newCFBStream(block, err, key, iv, doe)
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}
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func newCast5Stream(key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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block, err := cast5.NewCipher(key)
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return newCFBStream(block, err, key, iv, doe)
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}
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func newRC4MD5Stream(key, iv []byte, _ DecOrEnc) (cipher.Stream, error) {
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h := md5.New()
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h.Write(key)
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h.Write(iv)
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rc4key := h.Sum(nil)
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return rc4.NewCipher(rc4key)
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}
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func newChaCha20Stream(key, iv []byte, _ DecOrEnc) (cipher.Stream, error) {
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return chacha20.NewCipher(key, iv)
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}
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func newChacha20IETFStream(key, iv []byte, _ DecOrEnc) (cipher.Stream, error) {
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return chacha20.NewCipher(key, iv)
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}
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type salsaStreamCipher struct {
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nonce [8]byte
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key [32]byte
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counter int
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}
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func (c *salsaStreamCipher) XORKeyStream(dst, src []byte) {
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var buf []byte
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padLen := c.counter % 64
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dataSize := len(src) + padLen
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if cap(dst) >= dataSize {
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buf = dst[:dataSize]
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} else if leakybuf.GlobalLeakyBufSize >= dataSize {
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buf = leakybuf.GlobalLeakyBuf.Get()
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defer leakybuf.GlobalLeakyBuf.Put(buf)
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buf = buf[:dataSize]
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} else {
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buf = make([]byte, dataSize)
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}
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var subNonce [16]byte
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copy(subNonce[:], c.nonce[:])
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binary.LittleEndian.PutUint64(subNonce[len(c.nonce):], uint64(c.counter/64))
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// It's difficult to avoid data copy here. src or dst maybe slice from
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// Conn.Read/Write, which can't have padding.
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copy(buf[padLen:], src[:])
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salsa.XORKeyStream(buf, buf, &subNonce, &c.key)
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copy(dst, buf[padLen:])
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c.counter += len(src)
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}
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func newSalsa20Stream(key, iv []byte, _ DecOrEnc) (cipher.Stream, error) {
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var c salsaStreamCipher
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copy(c.nonce[:], iv[:8])
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copy(c.key[:], key[:32])
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return &c, nil
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}
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func newCamelliaStream(key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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block, err := camellia.New(key)
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return newCFBStream(block, err, key, iv, doe)
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}
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func newIdeaStream(key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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block, err := idea.NewCipher(key)
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return newCFBStream(block, err, key, iv, doe)
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}
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func newRC2Stream(key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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block, err := rc2.New(key, 16)
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return newCFBStream(block, err, key, iv, doe)
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}
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func newSeedStream(key, iv []byte, doe DecOrEnc) (cipher.Stream, error) {
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// TODO: SEED block cipher implementation is required
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block, err := rc2.New(key, 16)
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return newCFBStream(block, err, key, iv, doe)
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}
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type cipherInfo struct {
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keyLen int
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ivLen int
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newStream func(key, iv []byte, doe DecOrEnc) (cipher.Stream, error)
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}
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var streamCipherMethod = map[string]*cipherInfo{
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"aes-128-cfb": {16, 16, newAESCFBStream},
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"aes-192-cfb": {24, 16, newAESCFBStream},
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"aes-256-cfb": {32, 16, newAESCFBStream},
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"aes-128-ctr": {16, 16, newAESCTRStream},
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"aes-192-ctr": {24, 16, newAESCTRStream},
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"aes-256-ctr": {32, 16, newAESCTRStream},
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"aes-128-ofb": {16, 16, newAESOFBStream},
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"aes-192-ofb": {24, 16, newAESOFBStream},
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"aes-256-ofb": {32, 16, newAESOFBStream},
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"des-cfb": {8, 8, newDESStream},
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"bf-cfb": {16, 8, newBlowFishStream},
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"cast5-cfb": {16, 8, newCast5Stream},
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"rc4-md5": {16, 16, newRC4MD5Stream},
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"rc4-md5-6": {16, 6, newRC4MD5Stream},
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"chacha20": {32, 8, newChaCha20Stream},
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"chacha20-ietf": {32, 12, newChacha20IETFStream},
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"salsa20": {32, 8, newSalsa20Stream},
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"camellia-128-cfb": {16, 16, newCamelliaStream},
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"camellia-192-cfb": {24, 16, newCamelliaStream},
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"camellia-256-cfb": {32, 16, newCamelliaStream},
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"idea-cfb": {16, 8, newIdeaStream},
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"rc2-cfb": {16, 8, newRC2Stream},
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"seed-cfb": {16, 8, newSeedStream},
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}
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func CheckCipherMethod(method string) error {
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if method == "" {
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method = "rc4-md5"
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}
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_, ok := streamCipherMethod[method]
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if !ok {
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return errors.New("Unsupported encryption method: " + method)
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}
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return nil
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}
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type StreamCipher struct {
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enc cipher.Stream
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dec cipher.Stream
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key []byte
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info *cipherInfo
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iv []byte
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}
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// NewStreamCipher creates a cipher that can be used in Dial() etc.
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// Use cipher.Copy() to create a new cipher with the same method and password
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// to avoid the cost of repeated cipher initialization.
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func NewStreamCipher(method, password string) (c *StreamCipher, err error) {
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if password == "" {
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return nil, errEmptyPassword
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}
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if method == "" {
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method = "rc4-md5"
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}
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mi, ok := streamCipherMethod[method]
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if !ok {
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return nil, errors.New("Unsupported encryption method: " + method)
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}
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key := tools.EVPBytesToKey(password, mi.keyLen)
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c = &StreamCipher{key: key, info: mi}
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if err != nil {
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return nil, err
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}
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return c, nil
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}
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// Initializes the block cipher with CFB mode, returns IV.
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func (c *StreamCipher) initEncrypt() (iv []byte, err error) {
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if c.iv == nil {
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iv = make([]byte, c.info.ivLen)
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rand.Read(iv)
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c.iv = iv
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} else {
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iv = c.iv
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}
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c.enc, err = c.info.newStream(c.key, iv, Encrypt)
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return
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}
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func (c *StreamCipher) initDecrypt(iv []byte) (err error) {
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c.dec, err = c.info.newStream(c.key, iv, Decrypt)
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return
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}
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func (c *StreamCipher) encrypt(dst, src []byte) {
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c.enc.XORKeyStream(dst, src)
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}
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func (c *StreamCipher) decrypt(dst, src []byte) {
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c.dec.XORKeyStream(dst, src)
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}
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// Copy creates a new cipher at it's initial state.
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func (c *StreamCipher) Copy() *StreamCipher {
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// This optimization maybe not necessary. But without this function, we
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// need to maintain a table cache for newTableCipher and use lock to
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// protect concurrent access to that cache.
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// AES and DES ciphers does not return specific types, so it's difficult
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// to create copy. But their initialization time is less than 4000ns on my
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// 2.26 GHz Intel Core 2 Duo processor. So no need to worry.
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// Currently, blow-fish and cast5 initialization cost is an order of
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// magnitude slower than other ciphers. (I'm not sure whether this is
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// because the current implementation is not highly optimized, or this is
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// the nature of the algorithm.)
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nc := *c
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nc.enc = nil
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nc.dec = nil
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return &nc
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}
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func (c *StreamCipher) Key() (key []byte, keyLen int) {
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return c.key, c.info.keyLen
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}
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func (c *StreamCipher) IV() ([]byte, int) {
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return c.iv, c.info.ivLen
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}
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