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ENCRYPTION WITHOUT
MAGIC,
RISK MANAGEMENT
WITHOUT PAIN
@vixentael
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@vixentael Product Engineer
Feel free to reach me with
security questions.
I do check my inbox :)
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CRYPTOGRAPHY?
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CRYPTOGRAPHY?
AES
DES
3DES
CBC
CFB
SEAL
Salsa20
RSA
DSA
OFB
Blowfish
SHARK
RC4
DSS
ECB CTR
Twofish
Camelia
SEED
Rabbit
ECDSA
@vixentael
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MD5
SHA1
SHA256
HASHING PASSWORDS?
@vixentael
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MD5
SHA1
SHA256
HASHING PASSWORDS?
https://www.owasp.org/index.php/Password_Storage_Cheat_Sheet
https://dusted.codes/sha-256-is-not-a-secure-password-hashing-algorithm
HKDF
bcrypt
PBKDF2
@vixentael
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algorithms
elliptic curves
key management
public key validity
storing secrets
CRYPTOGRAPHY
cool, but… @vixentael
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crypto is not a
but a method to manage
the attack surface
@vixentael
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ATTACK SURFACE
– all the possible places
where sensitive data may be
stolen by adversary
https://www.owasp.org/index.php/Attack_Surface_Analysis_Cheat_Sheet @vixentael
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it’s easier to monitor
the suspicious behavior
in a small place
@vixentael
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HANDLING SENSITIVE DATA
WITH CARE
avoid plaintext as possible
manage keys properly
decrease time of plaintext secrets in memory
log, monitor and inspect
@vixentael
limit access to data
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– HOW TO MANAGE
THE ATTACK SURFACE
OF MY DATA?
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one container one key
@vixentael
symmetric encryption
with poor key
management
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attack surface
is arbitrary
one container one key
symmetric encryption
with poor key
management
key leaked
→ data leaked
@vixentael
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https://en.wikipedia.org/wiki/Cryptosystem @vixentael
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KEY AND TRUST
MANAGEMENT SHOULD
REFLECT YOUR SYSTEM
@vixentael
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MESSAGING
https://core.telegram.org/api/end-to-end
@vixentael
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GOOD MESSAGING
IS E2EE
…but your infrastructures
are not only for messaging @vixentael
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NAIVE DATABASE ENCRYPTION
attack surface
is almost everywhere
@vixentael
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NARROWING ATTACK SURFACE
middleware-side
encryption
client-side
encryption
@vixentael
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MIDDLEWARE-SIDE
ENCRYPTION
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SQL injections
code injections
execution flow attacks
reflection attacks
XSS
crypto-miners everywhere
MitM
REAL-WORLD WEB SERVER
@vixentael
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ATTACK SURFACE IS
EVERYWHERE :(
monitor everything
@vixentael
REAL-WORLD WEB SERVER
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TRY SYMMETRIC ENCRYPTION?
encrypt/decrypt data
using sym key
@vixentael
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encrypt/decrypt data
using sym key
easy to steal a key
https://www.alibabacloud.com/
help/faq-detail/37505.htm @vixentael
TRY SYMMETRIC ENCRYPTION?
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“COMBINED” ENCRYPTION
@vixentael
what if no decryption key?
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“COMBINED” ENCRYPTION
enc_data = Enc(data, Krand)
container = (enc_data, PubKweb, enc_key)
@vixentael
enc_key = Enc(Krand, PrivKweb, PubKtds)
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PubKey of ‘trusted
decryption service’
@vixentael
“COMBINED” ENCRYPTION
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TRUSTED DECRYPTION SERVICE
decrypts data
@vixentael
encrypts data
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trusted element in
infrastructure
SEPARATION OF DUTIES
no decryption
keys
monitor & log
@vixentael
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TRUSTED DECRYPTION SERVICE
@vixentael
NARROWED ATTACK
SURFACE
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monitor everything
monitor decryption proxy
@vixentael
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WHERE TO USE THIS
TECHNIQUE?
micro-services infrastructure
@vixentael
public-oriented interfaces
non-trusted client side (browsers, IoT devices)
hard to store keys securely
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HOW TO IMPLEMENT?
ACRA
https://github.com/cossacklabs/acra
GREEN SQL
https://github.com/larskanis/greensql-fw
HEXATIER
http://www.hexatier.com/
ORACLE DATABASE
FIREWALL / TDE
http://www.oracle.com/
@vixentael
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CLIENT-SIDE
ENCRYPTION
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MOVE TRUST TO CLIENTS
session hijacking
unattended backups
MitM
replay attacks
misconfigured ACL
trusted element in
infrastructure
@vixentael
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P2P TRUST
system doesn’t know
anything about data
encrypted
containers
user-generated
keys
@vixentael
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ZERO KNOWLEDGE
ARCHITECTURES
@vixentael
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ZKA is a design principle that
enables software to provide services
over protected client data without
having an unencrypted access to it.
@vixentael
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e2ee clients
@vixentael
ZKA INCLUDES:
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e2ee clients
all operations are on encrypted data:
– control access to data from different users
– CRUD
– search (in encrypted data)
ZKA INCLUDES:
@vixentael
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weak key management
algorithm weakness
user pocket
attack surface
RISKS FOR ZKA:
@vixentael
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WHEN TO USE ZKA?
trusted client side (mobile, HSM/TPM)
@vixentael
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ZKA is already solved for
specific use-cases or
in a naive ways
@vixentael
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MESSAGING END-TO-END
ENCRYPTION
@vixentael
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AUTHENTICATION ZERO KNOWLEDGE
PROOF
https://www.cossacklabs.com/zero-
knowledge-protocols-without-magic.html
@vixentael
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COLLABORATING
ON DATA
– store encrypted
– share with others
– manage access to
parties
???
@vixentael
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naive approach
– duplications
– key management
problems
SHARING ENCRYPTED DATA
@vixentael
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give access to
certain blocks of
data to exact users
github.com/cossacklabs/
hermes-core
CRYPTOGRAPHIC ACL
@vixentael
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– Key wrapping
storage keys user keys
blocks
HOW TO BUILD IT?
@vixentael
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– Key wrapping
– Manage privileges
@vixentael
HOW TO BUILD IT?
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– Key wrapping
– Manage privileges
– Control requests
@vixentael
HOW TO BUILD IT?
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shared
audit logs complex docs,
spreadsheets
config files
file system
document store
protection
MORE POSSIBLE USE-CASES
@vixentael
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HERMES
https://github.com/cossacklabs/hermes-core
ZEROKIT
https://tresorit.com/zerokit
LAFS
https://tahoe-lafs.org/trac/tahoe-lafs
@vixentael
IMPLEMENTATIONS
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monitor everything
monitor client side
@vixentael
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MORE GOODIES TO
THINK ABOUT
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Cryptography is well implemented,
if it allows to narrow attack surface,
and increase control of data.
@vixentael
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if the system has
one perimeter,
it will fail!
ECHELONIZATION
@vixentael
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#qconlondon @vixentael
..add more layers
of defense
ECHELONIZATION
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EXCEPT CRYPTO, YOU ALSO NEED
log and monitor events
credential management
access control, access logging
firewall, IDS, infrastructure management
...
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https://pdos.csail.mit.edu/papers/cryptobugs:apsys14.pdf
269 CVEs
from 2011-2014
17%
83%
bugs inside crypto libs
misuses of crypto libs
by individual apps
@vixentael
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2
RECAP
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THINGS TO REMEMBER
1. cryptography aims to narrow the attack surface
2. choose relevant encryption scheme
3. combine cryptography and classic security
techniques
@vixentael
4. echelonization, compartmentalization
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https://medium.freecodecamp.org/preventing-leaks-and-injections-in-your-database-
be3743af7614
How to prevent database leaks and injections
https://medium.com/@cossacklabs/12-and-1-ideas-how-to-enhance-backend-data-
security-4b8ceb5ccb88
12 and 1 ideas how to enhance backend data security
BACKEND SECURITY
https://www.cossacklabs.com/blog/gdpr-for-engineers.html
GDPR for engineers: technical requirements
https://samnewman.io/talks/insecure-transit-microservice-security/
Insecure Transit - Microservice Security
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CRYPTOGRAPHY
https://hackernoon.com/eli5-zero-knowledge-proof-78a276db9eff
Explain Like I’m 5: Zero Knowledge Proof
https://www.owasp.org/index.php/Secure_Coding_Cheat_Sheet
Secure Coding Cheat Sheet
https://www.owasp.org/index.php/OWASP_Secure_Coding_Practices_-
_Quick_Reference_Guide
Secure Coding Practices
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@vixentael
cryptographic software,
security consulting,
developers training
github.com/
vixentael/my-talks
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IMAGE CREDITS
www.flaticon.com
freepik, linector, switficons, pixelperfect, smashicons, icon pond,
dinosoftlabs
Authors: