vuvuzela

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 Go to latest Published: Dec 3, 2015 License: GPL-2.0 Imports: 18 Imported by: 0

README

Metadata absolutely tells you everything about somebody's life

— Stewart Baker, former General Counsel of the NSA

|

We kill people based on metadata

— Michael Hayden, former Director of the NSA

Vuvuzela

Vuvuzela is a messaging system that protects the privacy of message contents and message metadata. Users communicating through Vuvuzela do not reveal who they are talking to, even in the presence of powerful nation-state adversaries. Our SOSP 2015 paper explains the system, its threat model, performance, limitations, and more. Our SOSP 2015 slides give a more graphical overview of the system.

Vuvuzela is the first system that provides strong metadata privacy while scaling to millions of users. Previous systems that hide metadata using Tor (such as Pond) are prone to traffic analysis attacks. Systems that encrypt metadata using techniques like DC-nets and PIR don't scale beyond thousands of users.

Vuvuzela uses efficient cryptography (NaCl) to hide as much metadata as possible and adds noise to metadata that can't be encrypted efficiently. This approach provides less privacy than encrypting all of the metadata, but it enables Vuvuzela to support millions of users. Nonetheless, Vuvuzela adds enough noise to thwart adversaries like the NSA and guarantees differential privacy for users' metadata.

Screenshots

A conversation in the Vuvuzela client

client

In practice, the message latency would be around 20s to 40s, depending on security parameters and the number of users connected to the system.

Noise generated by the Vuvuzela servers

server

Vuvuzela is unable to encrypt two kinds of metadata: the number of idle users (connected users without a conversation partner) and the number of active users (users engaged in a conversation). Without noise, a sophisticated adversary could use this metadata to learn who is talking to who. However, the Vuvuzela servers generate noise that perturbs this metadata so that it is difficult to exploit.

Usage

Follow these steps to run the Vuvuzela system locally using the provided sample configs.

  1. Install Vuvuzela (assuming GOPATH=~/go, requires Go 1.4 or later):

     $ go get github.com/davidlazar/vuvuzela/...

The remaining steps assume PATH contains ~/go/bin and that the current working directory is ~/go/src/github.com/davidlazar/vuvuzela.

  1. Start the last Vuvuzela server:

     $ vuvuzela-server -conf confs/local-last.conf

  2. Start the middle server (in a new shell):

     $ vuvuzela-server -conf confs/local-middle.conf

  3. Start the first server (in a new shell):

     $ vuvuzela-server -conf confs/local-first.conf

  4. Start the entry server (in a new shell):

     $ vuvuzela-entry-server -wait 1s

  5. Run the Vuvuzela client:

     $ vuvuzela-client -conf confs/alice.conf

The client supports these commands:

  • /dial <user> to dial another user
  • /talk <user> to start a conversation
  • /talk <yourself> to end a conversation

Deployment considerations

This Vuvuzela implementation is not ready for wide-use deployment. In particular, we haven't yet implemented these crucial components:

  • Public Key Infrastructure: Vuvuzela assumes the existence of a PKI in which users can privately learn each others public keys. This implementation uses pki.conf as a placeholder until we integrate a real PKI.

  • CDN to distribute dialing dead drops: Vuvuzela's dialing protocol (used to initiate conversations) uses a lot of server bandwidth. To make dialing practical, Vuvuzela should use a CDN or BitTorrent to distribute the dialing dead drops.

There is a lot more interesting work to do. See the issue tracker for more information.

Acknowledgements

This code is written by David Lazar with contributions from Jelle van den Hooff, Nickolai Zeldovich, and Matei Zaharia.

Documentation

Overview

Types used by the entry server and client

Index

Constants

View Source 
const (
	SizeMessage = 240

	// Eventually this might be dynamic, but one bucket is usually
	// sufficient if users don't dial very often.
	TotalDialBuckets = 1

	DialWait           = 10 * time.Second
	DefaultReceiveWait = 5 * time.Second

	DefaultServerAddr = ":2718"
	DefaultServerPort = "2718"
)
View Source 
const (
	SizeEncryptedMessage = SizeMessage + box.Overhead
	SizeConvoExchange    = int(unsafe.Sizeof(ConvoExchange{}))
	SizeEncryptedIntro   = int(unsafe.Sizeof(Introduction{})) + onionbox.Overhead
	SizeDialExchange     = int(unsafe.Sizeof(DialExchange{}))
)

Variables

This section is empty.

Functions

func BackwardNonce 

func BackwardNonce(round uint32) *[24]byte

func FillWithFakeDoubles 

func FillWithFakeDoubles(dest [][]byte, nonce *[24]byte, nextKeys []*[32]byte)

func FillWithFakeIntroductions 

func FillWithFakeIntroductions(dest [][]byte, noiseCounts []int, nonce *[24]byte, nextKeys []*[32]byte)

func FillWithFakeSingles 

func FillWithFakeSingles(dest [][]byte, nonce *[24]byte, nextKeys []*[32]byte)

func ForwardNonce 

func ForwardNonce(round uint32) *[24]byte

func InitConvoService 

func InitConvoService(srv *ConvoService)

func InitDialService 

func InitDialService(srv *DialService)

func Intn 

func Intn(rand io.Reader, n int) int

func KeyDialBucket 

func KeyDialBucket(key *BoxKey, buckets uint32) uint32

func NewConvoRound 

func NewConvoRound(client *vrpc.Client, round uint32) error

func NewDialRound 

func NewDialRound(client *vrpc.Client, round uint32) error

func RunConvoRound 

func RunConvoRound(client *vrpc.Client, round uint32, onions [][]byte) ([][]byte, error)

func RunDialRound 

func RunDialRound(client *vrpc.Client, round uint32, onions [][]byte) error

Types

type AccessCount 

type AccessCount struct {
	Singles int64
	Doubles int64
}

type AnnounceConvoRound 

type AnnounceConvoRound struct {
	Round uint32
}

type AnnounceDialRound 

type AnnounceDialRound struct {
	Round   uint32
	Buckets uint32
}

type BadRequestError 

type BadRequestError struct {
	Err string
}

func (*BadRequestError) Error 

func (e *BadRequestError) Error() string

type BoxKey 

type BoxKey [32]byte

func GenerateBoxKey 

func GenerateBoxKey(rand io.Reader) (publicKey, privateKey *BoxKey, err error)

func KeyFromString 

func KeyFromString(s string) (*BoxKey, error)

func (*BoxKey) Key 

func (k *BoxKey) Key() *[32]byte

func (*BoxKey) MarshalJSON 

func (k *BoxKey) MarshalJSON() ([]byte, error)

func (*BoxKey) String 

func (k *BoxKey) String() string

func (*BoxKey) UnmarshalJSON 

func (k *BoxKey) UnmarshalJSON(b []byte) error

type BoxKeys 

type BoxKeys []*BoxKey

func (BoxKeys) Keys 

func (keys BoxKeys) Keys() []*[32]byte

type ConvoAddArgs 

type ConvoAddArgs struct {
	Round  uint32
	Offset int
	Onions [][]byte
}

type ConvoError 

type ConvoError struct {
	Round uint32
	Err   string
}

func (*ConvoError) Error 

func (e *ConvoError) Error() string

type ConvoExchange 

type ConvoExchange struct {
	DeadDrop         DeadDrop
	EncryptedMessage [SizeEncryptedMessage]byte
}

func (*ConvoExchange) Marshal 

func (e *ConvoExchange) Marshal() []byte

func (*ConvoExchange) Unmarshal 

func (e *ConvoExchange) Unmarshal(data []byte) error

type ConvoGetArgs 

type ConvoGetArgs struct {
	Round  uint32
	Offset int
	Count  int
}

type ConvoGetResult 

type ConvoGetResult struct {
	Onions [][]byte
}

type ConvoOpenArgs 

type ConvoOpenArgs struct {
	Round       uint32
	NumIncoming int
}

type ConvoRequest 

type ConvoRequest struct {
	Round uint32
	Onion []byte
}

type ConvoResponse 

type ConvoResponse struct {
	Round uint32
	Onion []byte
}

type ConvoRound 

type ConvoRound struct {
	// contains filtered or unexported fields
}

type ConvoService 

type ConvoService struct {
	Idle *sync.Mutex

	LaplaceMu float64
	LaplaceB  float64

	PKI        *PKI
	ServerName string
	PrivateKey *BoxKey
	Client     *vrpc.Client
	LastServer bool

	AccessCounts chan *AccessCount
	// contains filtered or unexported fields
}

func (*ConvoService) Add 

func (srv *ConvoService) Add(args *ConvoAddArgs, _ *struct{}) error

func (*ConvoService) Close 

func (srv *ConvoService) Close(Round uint32, _ *struct{}) error

func (*ConvoService) Delete 

func (srv *ConvoService) Delete(Round uint32, _ *struct{}) error

func (*ConvoService) Get 

func (srv *ConvoService) Get(args *ConvoGetArgs, result *ConvoGetResult) error

func (*ConvoService) NewRound 

func (srv *ConvoService) NewRound(Round uint32, _ *struct{}) error

func (*ConvoService) Open 

func (srv *ConvoService) Open(args *ConvoOpenArgs, _ *struct{}) error

type DeadDrop 

type DeadDrop [16]byte

type DialAddArgs 

type DialAddArgs struct {
	Round  uint32
	Onions [][]byte
}

type DialBucket 

type DialBucket struct {
	Round  uint32
	Intros [][SizeEncryptedIntro]byte
}

type DialBucketsArgs 

type DialBucketsArgs struct {
	Round uint32
}

type DialBucketsResult 

type DialBucketsResult struct {
	Buckets [][][SizeEncryptedIntro]byte
}

type DialError 

type DialError struct {
	Round uint32
	Err   string
}

func (*DialError) Error 

func (e *DialError) Error() string

type DialExchange 

type DialExchange struct {
	Bucket         uint32
	EncryptedIntro [SizeEncryptedIntro]byte
}

func (*DialExchange) Marshal 

func (e *DialExchange) Marshal() []byte

func (*DialExchange) Unmarshal 

func (e *DialExchange) Unmarshal(data []byte) error

type DialRequest 

type DialRequest struct {
	Round uint32
	Onion []byte
}

type DialRound 

type DialRound struct {
	sync.Mutex
	// contains filtered or unexported fields
}

type DialService 

type DialService struct {
	Idle *sync.Mutex

	LaplaceMu float64
	LaplaceB  float64

	PKI        *PKI
	ServerName string
	PrivateKey *BoxKey
	Client     *vrpc.Client
	LastServer bool
	// contains filtered or unexported fields
}

func (*DialService) Add 

func (srv *DialService) Add(args *DialAddArgs, _ *struct{}) error

func (*DialService) Buckets 

func (srv *DialService) Buckets(args *DialBucketsArgs, result *DialBucketsResult) error

func (*DialService) Close 

func (srv *DialService) Close(Round uint32, _ *struct{}) error

func (*DialService) NewRound 

func (srv *DialService) NewRound(Round uint32, _ *struct{}) error

type Envelope 

type Envelope struct {
	Type    MsgType
	Message json.RawMessage
}

func Envelop 

func Envelop(v interface{}) (*Envelope, error)

func (*Envelope) Open 

func (e *Envelope) Open() (interface{}, error)

type Introduction 

type Introduction struct {
	Rendezvous  uint32
	LongTermKey BoxKey
}

func (*Introduction) Marshal 

func (i *Introduction) Marshal() []byte

func (*Introduction) Unmarshal 

func (i *Introduction) Unmarshal(data []byte) error

type MsgType 

type MsgType uint8
const (
	// from client to server
	MsgConvoRequest MsgType = iota
	MsgDialRequest

	// from server to client
	MsgBadRequestError
	MsgConvoError
	MsgConvoResponse
	MsgDialError
	MsgDialBucket
	MsgAnnounceConvoRound
	MsgAnnounceDialRound
)

func (MsgType) String 

func (i MsgType) String() string

type PKI 

type PKI struct {
	People      map[string]*BoxKey
	Servers     map[string]*ServerInfo
	ServerOrder []string
	EntryServer string
}

func ReadPKI 

func ReadPKI(jsonPath string) *PKI

func (*PKI) FirstServer 

func (pki *PKI) FirstServer() string

func (*PKI) IncomingOnionOverhead 

func (pki *PKI) IncomingOnionOverhead(serverName string) int

func (*PKI) Index 

func (pki *PKI) Index(serverName string) int

func (*PKI) LastServer 

func (pki *PKI) LastServer() string

func (*PKI) NextServer 

func (pki *PKI) NextServer(serverName string) string

func (*PKI) NextServerKeys 

func (pki *PKI) NextServerKeys(serverName string) BoxKeys

func (*PKI) OutgoingOnionOverhead 

func (pki *PKI) OutgoingOnionOverhead(serverName string) int

func (*PKI) ServerKeys 

func (pki *PKI) ServerKeys() BoxKeys

type ServerInfo 

type ServerInfo struct {
	Address   string
	PublicKey *BoxKey
}

type Shuffler 

type Shuffler []int

func NewShuffler 

func NewShuffler(rand io.Reader, n int) Shuffler

func (Shuffler) Shuffle 

func (s Shuffler) Shuffle(x [][]byte)

func (Shuffler) Unshuffle 

func (s Shuffler) Unshuffle(x [][]byte)

Source Files

View all Source files

Directories

Path Synopsis
parallelfor.go by Jelle van den Hooff
 parallelfor.go by Jelle van den Hooff
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