Use Cryptography; Don't Learn It

Presentation from Swift and Fika conference.

We talked about securing data, and about mistakes developers make when they are trying to use encryption. And what they actually want from cryptography: they want high level functions, they want easy to use instruments that just works. They want boring crypto. But in a real world we have different levels of paranoia: from Faraday cage to hardware and software solutions. We named three layers of software solutions: boxed, crypto-systems and crypto-libs. And how to select which one to use. And about Edisson lamp as an example of boring, but working system.

Transcript

1. USE CRYPTOGRAPHY,
   DON’T LEARN IT.
   @vixentael
   

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2. @vixentael
   head of customer solutions,
   security software engineer
   OSS maintainer: Themis, Acra
   focused on applied crypto and
   building e2ee protocols
   Anastasiia Voitova
   

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3. database searchable encryption
   eprint.iacr.org/2019/806.pdf
   e2ee data collaboration
   cossacklabs.com/files/hermes-theory-paper-rev1.pdf
   zero knowledge authentication
   cossacklabs.com/files/secure-comparator-paper-rev12.pdf
   cossacklabs.com @vixentael
   Data security solutions based on R&D
   

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5. USABLE
   

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6. “Let’s protect stored data”
   …imagine simple use case
   …and calculate potential dev
   mistakes
   @vixentael
   

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7. 1. Defining the data scope
   business-sensitive data
   regulations, compliance
   tech data (keys, logs, backups, tokens..)
   @vixentael
   

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8. 1. Defining the data scope
   business-sensitive data
   regulations, compliance
   tech data (keys, logs, backups, tokens..)
   @vixentael
   Mistake 1.
   wrong scope definition
   

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9. 2. Selecting crypto function
   @vixentael
   twofish
   sha1
   des
   md5
   

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10. 2. Selecting crypto function
    @vixentael
    twofish
    sha1
    des
    md5
    Mistake 2.
    bad algo selection
    

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11. Things to decide on:
    KEY LENGTH
    DATA SCOPE CIPHER
    @vixentael
    

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12. 3. Using cipher
    @vixentael
    https://wiki.openssl.org/index.php/EVP_Symmetric_Encryption_and_Decryption
    

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13. 3. Using cipher
    @vixentael
    https://wiki.openssl.org/index.php/EVP_Symmetric_Encryption_and_Decryption
    

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14. 3. Using cipher
    @vixentael
    https://wiki.openssl.org/index.php/EVP_Symmetric_Encryption_and_Decryption
    Mistake 3.
    wrong params
    

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15. Things to decide on:
    PADDING
    KEY LENGTH
    MODE
    DATA SCOPE CIPHER
    IV
    @vixentael
    

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16. 4. Key management
    @vixentael
    user password
    DEK, KEK, master key, transport key,
    ephemeral key, OTP, token, keypairs …
    encryption key
    KDF
    

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17. 4. Key management
    @vixentael
    user password
    DEK, KEK, master key, transport key,
    ephemeral key, OTP, token, keypairs …
    encryption key
    KDF
    Mistake 4.
    bad key management
    https://www.owasp.org/index.php/Key_Management_Cheat_Sheet
    

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18. Things to decide on:
    PADDING
    KEY LENGTH
    KEY ROTATION
    MODE
    KEY DERIVATION KEY STORAGE
    KEY EXCHANGE
    DATA SCOPE CIPHER
    IV
    KEY REVOCATION
    KMS
    @vixentael
    

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19. 5. Infrastructure
    @vixentael
    

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20. Things to decide on:
    PADDING
    KEY LENGTH
    KEY ROTATION
    MODE
    KEY DERIVATION KEY STORAGE
    KEY EXCHANGE
    DATA SCOPE CIPHER
    IV
    KEY REVOCATION
    BACKUPS
    PLATFORMS
    KMS
    @vixentael
    

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22. 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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23. AES
    DES
    3DES
    CBC
    CFB
    SEAL
    Salsa20
    RSA
    DSA
    Kuznyechik
    Blowfish
    SHARK
    RC4
    DSS
    ChaCha20
    CTR
    AES-SIV
    Camelia
    SEED
    Rabbit
    ECDSA
    @vixentael
    

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24. — crypto that simply works, solidly
    resists attacks, never needs any
    upgrades
    https://cr.yp.to/talks/2015.10.05/slides-djb-20151005-a4.pdf
    Daniel J. Bernstein
    Boring crypto
    @vixentael
    

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25. I want to store data securely
    I want to send data securely
    I want to verify data integrity
    Solve use-cases
    @vixentael
    

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26. o store data securely
    o send data securely
    o verify data integrity KEY DERIVATION
    KEY EXCHANGE
    KEY ROTATION
    SIGN/VERIFY EPHEMERAL KEYS
    ENCR / DECR
    Solve use-cases
    @vixentael
    

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27. Crypto should be:
    cross-platform
    easy to install
    easy to use audited
    open source
    time proven
    well-documented
    compliant
    hard to mis-use
    @vixentael
    

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28. Form factor is important
    @vixentael
    

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29. encryption integration
    abstraction level
    complexity
    @vixentael
    

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30. encryption integration
    abstraction level
    complexity
    cipher
    crypto-
    library
    crypto-
    system
    boxed
    solution
    pain
    @vixentael
    

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31. 1. CRYPTO-LIBS
    implements single or multiple
    security functions
    https://github.com/sobolevn/awesome-cryptography @vixentael
    RNCryptor
    Themis
    OpenSSL/BoringSSL/*SSL
    CryptoSwift Tink
    LibSodium/NaCl
    

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32. Matthew Green
    @vixentael
    blog.cryptographyengineering.com/2012/12/28/the-anatomy-of-bad-idea/
    “OpenSSL is the space shuttle of crypto libraries. It will
    get you to space, provided you have a team of people to
    push the ten thousand buttons required to do so.
    NaCl is more like an elevator — you just press a button
    and it takes you there. No frills or options.
    I like elevators.”
    

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33. OpenSSL “high level” API, AES CBC
    @vixentael
    

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34. CommonCrypto AES
    @vixentael
    

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35. High lvl API, easy to mis-use
    @vixentael
    

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36. should be random
    should use KDF(key)
    uses AES CBC, not AES GCM
    padding? salt?
    
    High lvl API, easy to mis-use
    @vixentael
    

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37. github.com/cossacklabs/themis @vixentael
    Themis: hard to mis-use
    

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38. hides cryptographic details: salt, IV, KDF, padding
    uses AES-256-GCM
    github.com/cossacklabs/themis
    built-in KDF to make keys stronger
    Themis: hard to mis-use
    @vixentael
    

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39. 2. CRYPTO-SYSTEMS
    libsignal
    hermes SSL/TLS
    ZeroKit
    noise
    combines security functions for
    solving exact use-case
    @vixentael
    

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40. ACL based on crypto-keys
    @vixentael
    hermes
    python docs/examples/python/hermes_client.py
    --id USER1
    --config=docs/examples/python/config.json
    --private_key USER1.priv
    --doc secretfile
    --read
    

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41. 3. BOXED SOLUTIONS
    @vixentael
    unites crypto-systems and user
    functions for solving problems
    truecrypt
    ssh
    acra
    vault
    Oracle TDE
    

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42. transparent & searchable encryption
    @vixentael
    marketplace.digitalocean.com/apps/acra
    

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43. transparent & searchable encryption
    @vixentael
    marketplace.digitalocean.com/apps/acra
    very boring
    

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44. pain curve
    less boring more boring
    cipher
    crypto-
    library
    crypto-
    system
    boxed
    solution
    pain
    @vixentael
    

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45. Boring crypto tools allow to focus on
    product,
    not on crypto code.
    @vixentael
    

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46. @vixentael
    

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47. VS
    @vixentael
    

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48. make the light
    controllable
    @vixentael
    

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49. make the
    crypto security
    controllable
    and booooring
    @vixentael
    

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50. @vixentael
    Anastasiia Voitova
    github.com/vixentael/
    my-talks
    

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