package shadowsocks import ( "crypto/cipher" "crypto/md5" "errors" "v2ray.com/core/common/crypto" "v2ray.com/core/common/protocol" ) func (this *Account) GetCipher() (Cipher, error) { switch this.CipherType { case CipherType_AES_128_CFB: return &AesCfb{KeyBytes: 16}, nil case CipherType_AES_256_CFB: return &AesCfb{KeyBytes: 32}, nil case CipherType_CHACHA20: return &ChaCha20{IVBytes: 8}, nil case CipherType_CHACHA20_IEFT: return &ChaCha20{IVBytes: 12}, nil default: return nil, errors.New("Unsupported cipher.") } } func (this *Account) Equals(another protocol.Account) bool { if account, ok := another.(*Account); ok { return account.Password == this.Password } return false } func (this *Account) AsAccount() (protocol.Account, error) { return this, nil } func (this *Account) GetCipherKey() []byte { ct, err := this.GetCipher() if err != nil { return nil } return PasswordToCipherKey(this.Password, ct.KeySize()) } type Cipher interface { KeySize() int IVSize() int NewEncodingStream(key []byte, iv []byte) (cipher.Stream, error) NewDecodingStream(key []byte, iv []byte) (cipher.Stream, error) } type AesCfb struct { KeyBytes int } func (this *AesCfb) KeySize() int { return this.KeyBytes } func (this *AesCfb) IVSize() int { return 16 } func (this *AesCfb) NewEncodingStream(key []byte, iv []byte) (cipher.Stream, error) { stream := crypto.NewAesEncryptionStream(key, iv) return stream, nil } func (this *AesCfb) NewDecodingStream(key []byte, iv []byte) (cipher.Stream, error) { stream := crypto.NewAesDecryptionStream(key, iv) return stream, nil } type ChaCha20 struct { IVBytes int } func (this *ChaCha20) KeySize() int { return 32 } func (this *ChaCha20) IVSize() int { return this.IVBytes } func (this *ChaCha20) NewEncodingStream(key []byte, iv []byte) (cipher.Stream, error) { return crypto.NewChaCha20Stream(key, iv), nil } func (this *ChaCha20) NewDecodingStream(key []byte, iv []byte) (cipher.Stream, error) { return crypto.NewChaCha20Stream(key, iv), nil } func PasswordToCipherKey(password string, keySize int) []byte { pwdBytes := []byte(password) key := make([]byte, 0, keySize) md5Sum := md5.Sum(pwdBytes) key = append(key, md5Sum[:]...) for len(key) < keySize { md5Hash := md5.New() md5Hash.Write(md5Sum[:]) md5Hash.Write(pwdBytes) md5Hash.Sum(md5Sum[:0]) key = append(key, md5Sum[:]...) } return key }