Provable Security of (Tweakable) Block Ciphers Based on - - PowerPoint PPT Presentation

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Provable Security of (Tweakable) Block Ciphers Based on - - PowerPoint PPT Presentation

Jan 09, 2024 604 likes •1.04k views

Provable Security of (Tweakable) Block Ciphers Based on Substitution-Permutation Networks Benoit Cogliati Yevgeniy Dodis Jonathan Katz Jooyoung Lee John Steinberger John Steinberger Aishwarya Thiruvengadam Aishwarya Thiruvengadam Zhe Zhang

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Provable Security of (Tweakable) Block Ciphers Based on Substitution-Permutation Networks

Benoit Cogliati Yevgeniy Dodis Jonathan Katz Jooyoung Lee John Steinberger Aishwarya Thiruvengadam Zhe Zhang John Steinberger Aishwarya Thiruvengadam Zhe Zhang

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Block Ciphers

  • Building block for many cryptographic constructions

Hash functions

  • Hash functions
  • Encryption schemes
  • Message authentication codes
  • Keyed permutations
  • Popular Design Paradigms
  • Feistel Networks
  • Feistel Networks
  • Substitution-Permutation Networks

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Block Ciphers: Designs

  • Popular Design Paradigms

Feistel Network

  • Feistel Network
  • Eg: DES
  • Substitution-Permutation Network (SPN)
  • Eg: AES
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  • Popular Design Paradigms

Feistel Network

Block Ciphers: Designs

  • Feistel Network
  • Eg: DES
  • Long line of work analyzing provable security of Feistel [LR88, Pat03,

Pat04]

  • Security been studied in various security models [Pat10, HR10, HKT11,

Tes14, CHKPST16]

  • Substitution-Permutation Network (SPN)
  • Substitution-Permutation Network (SPN)
  • Eg: AES
  • In contrast, provable security of SPNs not as well-studied
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Related Work

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Related Work

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Substitution-Permutation Network (SPN)

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Substitution-Permutation Network (SPN)

. . .

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Substitution-Permutation Network (SPN)

. . .

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Substitution-Permutation Network (SPN)

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Substitution-Permutation Network (SPN)

. . .

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Substitution-Permutation Networks

Substitution- Permutation step

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Security of SPNs

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Security of SPNs

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Security of SPNs

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Security of SPNs

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Security of SPNs

  • Ideal World
  • Real World

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Categorizing SPNs

Linear function

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Categorizing SPNs

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Categorizing SPNs

Non-linear function

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Results: Linear SPNs

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Results: Non-linear SPNs

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Interpreting our Results

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Interpreting our Results

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Results

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Constructing Non-linear SPNs

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Constructing Non-linear SPNs: Blockwise Universal Permutations

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Constructing Non-linear SPNs: Blockwise Universal Permutations

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Constructing Non-linear SPNs: Blockwise Universal Permutations

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Non-linear SPNs via Blockwise Universal Permutations

. . .

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Non-linear SPNs via Blockwise Universal Permutations

. . .

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Non-linear SPNs via Blockwise Universal Permutations

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Results

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Security of 3-round linear SPN

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Security of 3-round Linear SPNs

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Results

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Takeaway

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Thank You

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Constructing Non-linear SPNs

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SPNs: Applications

1-round SPN

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Constructing Non-linear SPNs: Blockwise Universal Permutations