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