route/vendor/github.com/xtaci/kcp-go/crypt.go

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2017-03-26 19:50:20 +00:00
package kcp
import (
"crypto/aes"
"crypto/cipher"
"crypto/des"
"crypto/sha1"
"golang.org/x/crypto/blowfish"
"golang.org/x/crypto/cast5"
"golang.org/x/crypto/pbkdf2"
"golang.org/x/crypto/salsa20"
"golang.org/x/crypto/tea"
"golang.org/x/crypto/twofish"
"golang.org/x/crypto/xtea"
)
var (
initialVector = []byte{167, 115, 79, 156, 18, 172, 27, 1, 164, 21, 242, 193, 252, 120, 230, 107}
saltxor = `sH3CIVoF#rWLtJo6`
)
// BlockCrypt defines encryption/decryption methods for a given byte slice.
// Notes on implementing: the data to be encrypted contains a builtin
// nonce at the first 16 bytes
type BlockCrypt interface {
// Encrypt encrypts the whole block in src into dst.
// Dst and src may point at the same memory.
Encrypt(dst, src []byte)
// Decrypt decrypts the whole block in src into dst.
// Dst and src may point at the same memory.
Decrypt(dst, src []byte)
}
type salsa20BlockCrypt struct {
key [32]byte
}
// NewSalsa20BlockCrypt https://en.wikipedia.org/wiki/Salsa20
func NewSalsa20BlockCrypt(key []byte) (BlockCrypt, error) {
c := new(salsa20BlockCrypt)
copy(c.key[:], key)
return c, nil
}
func (c *salsa20BlockCrypt) Encrypt(dst, src []byte) {
salsa20.XORKeyStream(dst[8:], src[8:], src[:8], &c.key)
copy(dst[:8], src[:8])
}
func (c *salsa20BlockCrypt) Decrypt(dst, src []byte) {
salsa20.XORKeyStream(dst[8:], src[8:], src[:8], &c.key)
copy(dst[:8], src[:8])
}
type twofishBlockCrypt struct {
encbuf []byte
decbuf []byte
block cipher.Block
}
// NewTwofishBlockCrypt https://en.wikipedia.org/wiki/Twofish
func NewTwofishBlockCrypt(key []byte) (BlockCrypt, error) {
c := new(twofishBlockCrypt)
block, err := twofish.NewCipher(key)
if err != nil {
return nil, err
}
c.block = block
c.encbuf = make([]byte, twofish.BlockSize)
c.decbuf = make([]byte, 2*twofish.BlockSize)
return c, nil
}
func (c *twofishBlockCrypt) Encrypt(dst, src []byte) { encrypt(c.block, dst, src, c.encbuf) }
func (c *twofishBlockCrypt) Decrypt(dst, src []byte) { decrypt(c.block, dst, src, c.decbuf) }
type tripleDESBlockCrypt struct {
encbuf []byte
decbuf []byte
block cipher.Block
}
// NewTripleDESBlockCrypt https://en.wikipedia.org/wiki/Triple_DES
func NewTripleDESBlockCrypt(key []byte) (BlockCrypt, error) {
c := new(tripleDESBlockCrypt)
block, err := des.NewTripleDESCipher(key)
if err != nil {
return nil, err
}
c.block = block
c.encbuf = make([]byte, des.BlockSize)
c.decbuf = make([]byte, 2*des.BlockSize)
return c, nil
}
func (c *tripleDESBlockCrypt) Encrypt(dst, src []byte) { encrypt(c.block, dst, src, c.encbuf) }
func (c *tripleDESBlockCrypt) Decrypt(dst, src []byte) { decrypt(c.block, dst, src, c.decbuf) }
type cast5BlockCrypt struct {
encbuf []byte
decbuf []byte
block cipher.Block
}
// NewCast5BlockCrypt https://en.wikipedia.org/wiki/CAST-128
func NewCast5BlockCrypt(key []byte) (BlockCrypt, error) {
c := new(cast5BlockCrypt)
block, err := cast5.NewCipher(key)
if err != nil {
return nil, err
}
c.block = block
c.encbuf = make([]byte, cast5.BlockSize)
c.decbuf = make([]byte, 2*cast5.BlockSize)
return c, nil
}
func (c *cast5BlockCrypt) Encrypt(dst, src []byte) { encrypt(c.block, dst, src, c.encbuf) }
func (c *cast5BlockCrypt) Decrypt(dst, src []byte) { decrypt(c.block, dst, src, c.decbuf) }
type blowfishBlockCrypt struct {
encbuf []byte
decbuf []byte
block cipher.Block
}
// NewBlowfishBlockCrypt https://en.wikipedia.org/wiki/Blowfish_(cipher)
func NewBlowfishBlockCrypt(key []byte) (BlockCrypt, error) {
c := new(blowfishBlockCrypt)
block, err := blowfish.NewCipher(key)
if err != nil {
return nil, err
}
c.block = block
c.encbuf = make([]byte, blowfish.BlockSize)
c.decbuf = make([]byte, 2*blowfish.BlockSize)
return c, nil
}
func (c *blowfishBlockCrypt) Encrypt(dst, src []byte) { encrypt(c.block, dst, src, c.encbuf) }
func (c *blowfishBlockCrypt) Decrypt(dst, src []byte) { decrypt(c.block, dst, src, c.decbuf) }
type aesBlockCrypt struct {
encbuf []byte
decbuf []byte
block cipher.Block
}
// NewAESBlockCrypt https://en.wikipedia.org/wiki/Advanced_Encryption_Standard
func NewAESBlockCrypt(key []byte) (BlockCrypt, error) {
c := new(aesBlockCrypt)
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
c.block = block
c.encbuf = make([]byte, aes.BlockSize)
c.decbuf = make([]byte, 2*aes.BlockSize)
return c, nil
}
func (c *aesBlockCrypt) Encrypt(dst, src []byte) { encrypt(c.block, dst, src, c.encbuf) }
func (c *aesBlockCrypt) Decrypt(dst, src []byte) { decrypt(c.block, dst, src, c.decbuf) }
type teaBlockCrypt struct {
encbuf []byte
decbuf []byte
block cipher.Block
}
// NewTEABlockCrypt https://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm
func NewTEABlockCrypt(key []byte) (BlockCrypt, error) {
c := new(teaBlockCrypt)
block, err := tea.NewCipherWithRounds(key, 16)
if err != nil {
return nil, err
}
c.block = block
c.encbuf = make([]byte, tea.BlockSize)
c.decbuf = make([]byte, 2*tea.BlockSize)
return c, nil
}
func (c *teaBlockCrypt) Encrypt(dst, src []byte) { encrypt(c.block, dst, src, c.encbuf) }
func (c *teaBlockCrypt) Decrypt(dst, src []byte) { decrypt(c.block, dst, src, c.decbuf) }
type xteaBlockCrypt struct {
encbuf []byte
decbuf []byte
block cipher.Block
}
// NewXTEABlockCrypt https://en.wikipedia.org/wiki/XTEA
func NewXTEABlockCrypt(key []byte) (BlockCrypt, error) {
c := new(xteaBlockCrypt)
block, err := xtea.NewCipher(key)
if err != nil {
return nil, err
}
c.block = block
c.encbuf = make([]byte, xtea.BlockSize)
c.decbuf = make([]byte, 2*xtea.BlockSize)
return c, nil
}
func (c *xteaBlockCrypt) Encrypt(dst, src []byte) { encrypt(c.block, dst, src, c.encbuf) }
func (c *xteaBlockCrypt) Decrypt(dst, src []byte) { decrypt(c.block, dst, src, c.decbuf) }
type simpleXORBlockCrypt struct {
xortbl []byte
}
// NewSimpleXORBlockCrypt simple xor with key expanding
func NewSimpleXORBlockCrypt(key []byte) (BlockCrypt, error) {
c := new(simpleXORBlockCrypt)
c.xortbl = pbkdf2.Key(key, []byte(saltxor), 32, mtuLimit, sha1.New)
return c, nil
}
func (c *simpleXORBlockCrypt) Encrypt(dst, src []byte) { xorBytes(dst, src, c.xortbl) }
func (c *simpleXORBlockCrypt) Decrypt(dst, src []byte) { xorBytes(dst, src, c.xortbl) }
type noneBlockCrypt struct{}
// NewNoneBlockCrypt does nothing but copying
func NewNoneBlockCrypt(key []byte) (BlockCrypt, error) {
return new(noneBlockCrypt), nil
}
func (c *noneBlockCrypt) Encrypt(dst, src []byte) { copy(dst, src) }
func (c *noneBlockCrypt) Decrypt(dst, src []byte) { copy(dst, src) }
// packet encryption with local CFB mode
func encrypt(block cipher.Block, dst, src, buf []byte) {
blocksize := block.BlockSize()
tbl := buf[:blocksize]
block.Encrypt(tbl, initialVector)
n := len(src) / blocksize
base := 0
for i := 0; i < n; i++ {
xorWords(dst[base:], src[base:], tbl)
block.Encrypt(tbl, dst[base:])
base += blocksize
}
xorBytes(dst[base:], src[base:], tbl)
}
func decrypt(block cipher.Block, dst, src, buf []byte) {
blocksize := block.BlockSize()
tbl := buf[:blocksize]
next := buf[blocksize:]
block.Encrypt(tbl, initialVector)
n := len(src) / blocksize
base := 0
for i := 0; i < n; i++ {
block.Encrypt(next, src[base:])
xorWords(dst[base:], src[base:], tbl)
tbl, next = next, tbl
base += blocksize
}
xorBytes(dst[base:], src[base:], tbl)
}