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Bootstrapping Secure Communication without Leaking Metadata

Home Page: https://vuvuzela.io

License: Other

Go 98.89% Yacc 1.11%

metadata privacy messaging vuvuzela golang cryptography research pki

alpenhorn's Introduction

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

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

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.

Acknowledgements

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

alpenhorn's People

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cmnord hiterzhou cuongttran kata sohui62 lakeoffaith myl7

alpenhorn's Issues

pretty empty looking repo

read the paper just now....

Freshness of signed configs

There currently isn't a good way to verify the (short-term) freshness of signed configs. The configs have an expiration date, but those are typically long-term.

Error when trying to install vuvuzela-client

$ go get -u vuvuzela.io/vuvuzela/cmd/vuvuzela-client
# vuvuzela.io/alpenhorn/pkg
go/src/vuvuzela.io/alpenhorn/pkg/server.go:89:6: opts.Dir undefined (type func(string) badger.Options has no field or method Dir)
go/src/vuvuzela.io/alpenhorn/pkg/server.go:90:6: opts.ValueDir undefined (type func(string) badger.Options has no field or method ValueDir)
go/src/vuvuzela.io/alpenhorn/pkg/server.go:91:6: opts.SyncWrites undefined (type func(string) badger.Options has no field or method SyncWrites)
go/src/vuvuzela.io/alpenhorn/pkg/server.go:93:24: cannot use opts (type func(string) badger.Options) as type badger.Options in argument to badger.Open

Apparently that is related to breaking API changes:
https://github.com/dgraph-io/badger/releases/tag/v1.6.0

Problem now is, when I change the version of badger I get this:

$ go build
# vuvuzela.io/alpenhorn/pkg
../alpenhorn/pkg/data.go:131:7: assignment mismatch: 1 variable but item.Value returns 2 values
../alpenhorn/pkg/data.go:131:20: too many arguments in call to item.Value
	have (func([]byte) error)
	want ()
../alpenhorn/pkg/data.go:154:7: assignment mismatch: 1 variable but item.Value returns 2 values
../alpenhorn/pkg/data.go:154:19: too many arguments in call to item.Value
	have (func([]byte) error)
	want ()
../alpenhorn/pkg/extract.go:222:6: assignment mismatch: 1 variable but item.Value returns 2 values
../alpenhorn/pkg/extract.go:222:18: too many arguments in call to item.Value
	have (func([]byte) error)
	want ()
../alpenhorn/pkg/register.go:102:17: not enough arguments in call to tx.Commit
	have ()
	want (func(error))

Due to my non-existent knowledge of programming in Go, I had to hack this in an ugly way. But hey, better than nothing!

Workaround

go get -u vuvuzela.io/vuvuzela/cmd/vuvuzela-client

cd "$GOPATH/src/github.com/dgraph-io/badger"

No. None of the tagged versions work. Use this commit.

git checkout 50bef1d5c7be94eed748c17ae55a4de94b8ba165

cd "$GOPATH/src/vuvuzela.io/vuvuzela/cmd/vuvuzela-client"

Basically building vuvuzela-client now.

go build main.go gui.go conversation.go notify.go alpenhorn.go commands.go connect.go

./main -username [email protected]

You probably could move the executable to pretend you installed vuvuzela as intended:

mv main "$GOPATH/bin/vuvuzela-client"

Add new PKG protocol

When adding a new PKG we might want to do something like: temporarily stop all registrations at the existing PKGs, have each existing PKG send a signed copy of its users database to the new PKG, and then have the new PKG pre-populate its users database by merging the existing databases before re-enabling registrations. To merge databases, the new PKG should only accept a user record if the all the other PKGs agree on it; otherwise, it should ask the user to register (and verify their email address).

Upgrade client and connect: apparent errors

I upgraded after two years:

$ /usr/lib/go-1.10/bin/go get -u vuvuzela.io/vuvuzela/cmd/vuvuzela-client
package crypto/ed25519: unrecognized import path "crypto/ed25519" (import path does not begin with hostname)
package github.com/godbus/dbus/v5: cannot find package "github.com/godbus/dbus/v5" in any of:
        /usr/lib/go-1.10/src/github.com/godbus/dbus/v5 (from $GOROOT)
        /home/dev/go/src/github.com/godbus/dbus/v5 (from $GOPATH)
package google.golang.org/genproto/googleapis/rpc/status: google.golang.org/genproto is a custom import path for https://github.com/googleapis/go-genproto, but /home/dev/go/src/google.golang.org/genproto is checked out from https://github.com/google/go-genproto

I was curious if the md5 of the client would change, so I checked it before and after. It did not:

901cb30ede47e5b7d5d19bdd68422b69 vuvuzela-client

Then I ran the client and /connect:

 -!- Connection error: inconsistent PKG status for "XXXXXXX":
  ·  PKG pkg1.vuvuzela.io:8443: Post https://pkg1.vuvuzela.io:8443/status: read tcp 10.18.0.3:56142->128.52.176.147:8443: read: connection reset by peer
  ·  PKG nickolai.srv.vuvuzela.io:54331: Post https://nickolai.srv.vuvuzela.io:54331/status: read tcp 10.18.0.3:54780->50.202.194.198:54331: read: connection reset by peer
  ·  PKG pkg2.vuvuzela.io:8443: Post https://pkg2.vuvuzela.io:8443/status: read tcp 10.18.0.3:39762->128.31.25.215:8443: read: connection reset by peer
 -!- Type /connect after resolving the issue to try again.