Slide 1
Slide 1 text
ZERO KNOWLEDGE
ARCHITECTURES
for mobile applications
Slide 2
Slide 2 text
@vixentael Mobile
Tech Lead
Feel free to reach me with any
mobile security questions.
I do check my inbox :)
Slide 3
Slide 3 text
Let’s play a game
Slide 4
Slide 4 text
Sensitive data – ?
@vixentael
Slide 5
Slide 5 text
E2EE – ?
@vixentael
Slide 6
Slide 6 text
GDPR – ?
@vixentael
Slide 7
Slide 7 text
GDPR – ?
Equifax – ?
@vixentael
Slide 8
Slide 8 text
#mobiconf @vixentael
Slide 9
Slide 9 text
Where we are
Slide 10
Slide 10 text
We have sensitive data
@vixentael
Slide 11
Slide 11 text
We have sensitive data
We put it to the “cloud”
@vixentael
Slide 12
Slide 12 text
We put it to the “cloud”
Slide 13
Slide 13 text
We put it to the “cloud”
Everything runs
on smbd’s software, on smbd’s computer,
is maintained by someone else
@vixentael
Slide 14
Slide 14 text
We have sensitive data
We put it to the “cloud”
Everything runs
on smbd’s software, on smbd’s computer,
is maintained by someone else
@vixentael
Slide 15
Slide 15 text
Do we trust them?
@vixentael
Slide 16
Slide 16 text
Do we trust them?
Do we want to trust them?
@vixentael
Slide 17
Slide 17 text
– NO.
Slide 18
Slide 18 text
We don’t want.
@vixentael
Slide 19
Slide 19 text
to know how secure cloud is
We don’t want
@vixentael
Slide 20
Slide 20 text
to trust other ppl’s software,
computers, and maintenance
practices
- to know how secure cloud is
We don’t want
@vixentael
Slide 21
Slide 21 text
to think about sensitive data
leakage
- to trust other people’s software, computers, and
maintenance practices
- to know how secure cloud is
We don’t want
@vixentael
Slide 22
Slide 22 text
- to think about sensitive data leakage
- to trust other people’s software, computers, and
maintenance practices
- to know how secure cloud is
We don’t want
@vixentael
Slide 23
Slide 23 text
No content
Slide 24
Slide 24 text
We don’t want to share
sensitive data.
Slide 25
Slide 25 text
We don’t want to share
sensitive data,
but we must
Slide 26
Slide 26 text
medical records
credit history
?
}
@vixentael
Slide 27
Slide 27 text
your data,
managed
by someone
medical records
credit history
=
@vixentael
Slide 28
Slide 28 text
– Need control.
Slide 29
Slide 29 text
Control access to the sensitive
data during storing and sharing.
@vixentael
Slide 30
Slide 30 text
How?
Control access to the sensitive
data during storing and sharing.
@vixentael
Slide 31
Slide 31 text
– Encryption.
Slide 32
Slide 32 text
Messaging End-to-End
Encryption
@vixentael
Slide 33
Slide 33 text
Authentication Zero Knowledge
Proof
https://www.cossacklabs.com/zero-
knowledge-protocols-without-magic.html
@vixentael
Slide 34
Slide 34 text
Data ???
- store encrypted
- share with others
- manage access to
parties
@vixentael
Slide 35
Slide 35 text
– Zero Knowledge
Architectures
Slide 36
Slide 36 text
ZKA is a design principle that
enables software to provide
services over protected client data
without having an unencrypted
access to it.
@vixentael
Slide 37
Slide 37 text
e2ee clients
ZKA includes
@vixentael
Slide 38
Slide 38 text
e2ee clients
all operations are on encrypted data:
– control access to data from different users
– CRUD
– search (in encrypted data)
ZKA includes
@vixentael
Slide 39
Slide 39 text
ZKA is already solved for
specific use-cases or
in a naive ways
@vixentael
Slide 40
Slide 40 text
Sharing encrypted data:
naive approach
– duplications
– key management
problems
@vixentael
Slide 41
Slide 41 text
give access to
certain blocks of
data to exact users
https://github.com/cossacklabs/
hermes-core
Our take
@vixentael
Slide 42
Slide 42 text
- Why me?
Slide 43
Slide 43 text
ZKA relies on trust to the client
@vixentael
Slide 44
Slide 44 text
ZKA relies on trust to the client
Mobile runs code safely*
@vixentael
Slide 45
Slide 45 text
ZKA relies on trust to the client
Mobile stores keys safely*
Mobile runs code safely*
@vixentael
Slide 46
Slide 46 text
Mobile stores keys safely*
ZKA relies on trust to the client
Mobile runs code safely*
Mobile is a good client Brent
@vixentael
Slide 47
Slide 47 text
– Meanwhile in
the real world…
Slide 48
Slide 48 text
No content
Slide 49
Slide 49 text
{
"personal_data": {
"name": "Cat",
"surname": "Black",
"age": 25,
"home_address": "large box in living room",
"birth_date": "01/04/1992"
},
"credit_rating": 8.7,
"transactions": [{
"operation": "credit",
"bank": "CatBank1",
"amount": "2000",
"currency": "eur",
"date": "02/10/2017"
},
{
"operation": "credit",
"bank": "CatBank2",
"amount": "500",
"currency": "eur",
"date": "14/02/2015"
}
]
} @vixentael
Slide 50
Slide 50 text
{
"personal_data": {
"name": "Cat",
"surname": "Black",
"age": 25,
"home_address": "large box in living room",
"birth_date": "01/04/1992"
},
"credit_rating": 8.7,
"transactions": [{
"operation": "credit",
"bank": "CatBank1",
"amount": "2000",
"currency": "eur",
"date": "02/10/2017"
},
{
"operation": "credit",
"bank": "CatBank2",
"amount": "500",
"currency": "eur",
"date": "14/02/2015"
}
]
}
personal data
@vixentael
Slide 51
Slide 51 text
protected data
{
"personal_data": {
"name": "Cat",
"surname": "Black",
"age": 25,
"home_address": "large box in living room",
"birth_date": "01/04/1992"
},
"credit_rating": 8.7,
"transactions": [{
"operation": "credit",
"bank": "CatBank1",
"amount": "2000",
"currency": "eur",
"date": "02/10/2017"
},
{
"operation": "credit",
"bank": "CatBank2",
"amount": "500",
"currency": "eur",
"date": "14/02/2015"
}
]
} @vixentael
Slide 52
Slide 52 text
{
"personal_data": {
"name": "Cat",
"surname": "Black",
"age": 25,
"home_address": "large box in living room",
"birth_date": "01/04/1992"
},
"credit_rating": 8.7,
"transactions": [{
"operation": "credit",
"bank": "CatBank1",
"amount": "2000",
"currency": "eur",
"date": "02/10/2017"
},
{
"operation": "credit",
"bank": "CatBank2",
"amount": "500",
"currency": "eur",
"date": "14/02/2015"
}
]
}
really-really
protected data
@vixentael
Slide 53
Slide 53 text
you
bank
credit
bureau
@vixentael
Slide 54
Slide 54 text
you
bank
credit
bureau
@vixentael
Slide 55
Slide 55 text
you
bank
credit
bureau
@vixentael
Slide 56
Slide 56 text
you
bank
credit
bureau
@vixentael
Slide 57
Slide 57 text
you
bank
credit
bureau
@vixentael
Slide 58
Slide 58 text
you
bank
credit
bureau
@vixentael
Slide 59
Slide 59 text
you
bank
credit
bureau
what could possibly go wrong?
@vixentael
Slide 60
Slide 60 text
leakage from –
your data is available everywhere
Risks
@vixentael
Slide 61
Slide 61 text
leakage from –
your data is available everywhere
Risks
encrypt data with one shared ?
leak one key – leak everything
@vixentael
Slide 62
Slide 62 text
B&B can accumulate extra data
about you.
Risks
@vixentael
Slide 63
Slide 63 text
B&B can judge you by things
you haven’t done.
Risks
@vixentael
Slide 64
Slide 64 text
B&B can record requests about
people they don’t know.
Risks
@vixentael
Slide 65
Slide 65 text
How ZKA can help?
Slide 66
Slide 66 text
{
"personal_data": {
"name": "Cat",
"surname": "Black",
"age": 25,
"home_address": "large box in living room",
"birth_date": "01/04/1992"
},
"credit_rating": 8.7,
"transactions": [{
"operation": "credit",
"bank": "CatBank1",
"amount": "2000",
"currency": "eur",
"date": "02/10/2017"
},
{
"operation": "credit",
"bank": "CatBank2",
"amount": "500",
"currency": "eur",
"date": "14/02/2015"
}
]
}
RW
RO
RO, customer
verification
RW
@vixentael
Slide 67
Slide 67 text
access to data
blocks
encrypted
controlled by
owner
@vixentael
Slide 68
Slide 68 text
stores encrypted
updates only credit score
owns,
controls access
RW only their
transactions
access
revoked
@vixentael
Slide 69
Slide 69 text
- Key wrapping
storage keys user keys
How to build it?
@vixentael
blocks
Slide 70
Slide 70 text
- Key wrapping
- Manage privileges
How to build it?
@vixentael
Slide 71
Slide 71 text
- Key wrapping
- Manage privileges
- Control requests
How to build it?
@vixentael
Slide 72
Slide 72 text
- Key wrapping
- Manage privileges
- Control requests
- Mitigate remaining attacks
How to build it?
@vixentael
Slide 73
Slide 73 text
leakage →
privileges →
replay →
other? →
Mitigating the risks:
@vixentael
Slide 74
Slide 74 text
leakage → it’s encrypted
privileges →
replay →
other? →
Mitigating the risks:
@vixentael
Slide 75
Slide 75 text
leakage → it’s encrypted
privileges → it’s encrypted
replay →
other? →
Mitigating the risks:
@vixentael
Slide 76
Slide 76 text
leakage → it’s encrypted
privileges → it’s encrypted
replay → ZKP (it’s encrypted ;)
other? →
Mitigating the risks:
@vixentael
Slide 77
Slide 77 text
leakage → it’s encrypted
privileges → it’s encrypted
replay → ZKP (it’s encrypted ;)
other? → tiny attack surface
Mitigating the risks:
@vixentael
Slide 78
Slide 78 text
ZKA elsewhere
Slide 79
Slide 79 text
shared
audit logs
complex docs,
spreadsheets
config files
file system
document store
protection
@vixentael
Slide 80
Slide 80 text
Is it difficult
to implement?
Slide 81
Slide 81 text
Signal https://github.com/WhisperSystems/
SignalProtocolKit/blob/master/AxolotlKit/Classes/
Sessions/SessionBuilder.m
@vixentael
Slide 82
Slide 82 text
Swift Alps Demo https://github.com/cossacklabs/theswiftalpsdemo/
blob/master/ios-project/SwiftAlpsSecDemo/
SwiftAlpsSecDemo/SessionDemo.swift
github.com/
cossacklabs/themis
@vixentael
Slide 83
Slide 83 text
Hermes
github.com/cossacklabs/
hermes-core
ODING IN PROGRESS
CODING IN PROG @vixentael
Slide 84
Slide 84 text
Other examples
https://tahoe-lafs.org/trac/tahoe-lafs
The Least-Authority File Store
https://tresorit.com/zerokit
ZeroKit from Tresorit
@vixentael
Slide 85
Slide 85 text
Recap
Slide 86
Slide 86 text
1. We know a lot about data protection and
peer-to-peer communication.
2. Collaborating on data exposes more
advanced risks. One key is not enough.
3. ZKA helps against advanced risks.
4. Sooner or later, everything will be
collaborative.
5. Learn ZKA in advance!
@vixentael
Slide 87
Slide 87 text
Links 1
https://clipperz.is/blog/2007/08/24/anatomy_zero_knowledge_web_application/
Anatomy of a Zero-Knowledge Web Application, 2007
https://www.cossacklabs.com/zero-knowledge-protocols-without-magic.html
Zero Knowledge Protocols Without Magic
https://brainsware.at/blog/9-zero-knowledge-saas
Why We Develop Zero Knowledge Software
Slide 88
Slide 88 text
Links 2
https://spideroak.com/articles/why-we-will-no-longer-use-the-phrase-zero-
knowledge-to-describe-our-software/
Why We Will No Longer Use the Phrase Zero Knowledge to
Describe Our Software
https://medium.com/@cossacklabs/eli5-end-to-end-encryption-ae46821db74f
Explain Like I’m 5: End-to-end Encryption
https://keybase.io/blog/encrypted-git-for-everyone
Keybase launches encrypted git
Slide 89
Slide 89 text
My other security slides
https://github.com/
vixentael/my-talks
Slide 90
Slide 90 text
@vixentael Mobile
Tech Lead
Feel free to reach me with any
mobile security questions.
I do check my inbox :)
Slide 91
Slide 91 text
Image credits
www.flaticon.com
freepik, linector, switficons, pixelperfect, smashicons
Authors: