Yael%20Tauman%20Kalai

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Yael Tauman Kalai

• Area Cryptography
• PhD MIT, with Shafi Goldwasser
• IBM PhD Fellowship
• MIT Presidential Graduate Fellowship
• Masters Weizmann, with Adi Shamir
• Outstanding Masters Thesis Prize

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Yael Tauman Kalai

• Main results
• Ring signatures
• Fiat-Shamir heuristic
• Code obfuscation

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Fiat-Shamir Heuristic (1986)

• Transforms identification protocol into signature
• Efficient used in practice.
• with Goldwasser Heuristic is insecure.
• First example of ID protocol where Fiat-Shamir
  transform yields insecure signature.

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Letters

• Letters emphasize originality and creativity
• Letter writers
• Goldwasser
• Rivest
• Shamir
• Ran Raz
• top 5 in 7 years from Weizmann
• top 3-5 in 11 years from Weizmann

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• Goldwasser
• one of 2 or 3 most original and unconventional
  graduate students
• brilliant, original, technically superb
• Compare to Boaz Barak, Joe Kilian

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• Rivest
• one of the very top students graduating from our
  group this year
• works on some of the most interesting, cutting
  edge and fundamental problems in the field today
• shows real mastery of the field
• very strong in the fundamentals and in terms of
  raw theoretical power

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How to Leak a Secretwith Rivest and Shamir

• Goals
• Anonymity.
• Proof that info from high-ranking official.
• Ring Signatures
• Pick set S of people with public keys, including
  self.
• Members of S dont have to cooperate.
• Others can verify that someone in S signed.
• Nobody knows which person in S.
• Very efficient, even for many people.

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How to Leak a Secretwith Rivest and Shamir

• Goals
• Anonymity.
• Proof that info from high-ranking official.
• Ring Signatures
• Pick set S of people with public keys, including
  self.
• Members of S dont have to cooperate.
• Others can verify that someone in S signed.
• Nobody knows which person in S.
• Very efficient, even for many people.
• Other Applications
• Prevent phishing attacks.
• Many follow-up papers.

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Code Obfuscation

• Code ? unintelligible code, same functionality.
• Prevent hackers from learning anything when they
  examine code.
• Very important in practice.
• Vitalys example phone book.

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Code Obfuscation

• Code ? unintelligible code, same functionality.
• Prevent hackers from learning anything when they
  examine code.
• Very important in practice.
• Vitalys example phone book.
• Obfuscate any private key crypto ? public key
  crypto.

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Code Obfuscation

• Code ? unintelligible code, same functionality.
• Prevent hackers from learning anything when they
  examine code.
• Very important in practice.
• Vitalys example phone book.
• Obfuscate any private key crypto ? public key
  crypto.
• BGIRSVY Impossible for artificial functions.
• Canetti, Wee Obfuscate certain functions.
• Possible for all natural functions?

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Code Obfuscation

• Code ? unintelligible code, same functionality.
• Prevent hackers from learning anything when they
  examine code.
• Very important in practice.
• Vitalys example phone book.
• Obfuscate any private key crypto ? public key
  crypto.
• BGIRSVY Impossible for artificial functions.
• Canetti, Wee Obfuscate certain functions.
• Possible for all natural functions?
• with Goldwasser Impossible for certain
  natural functions.
• Also give positive result.

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Fiat-Shamir Heuristic (1986)

• Transforms identification protocol into signature
• Efficient used in practice.
• Provably secure under random oracle model.

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Fiat-Shamir Heuristic (1986)

• Transforms identification protocol into signature
• Efficient used in practice.
• Provably secure under random oracle model.
• with Goldwasser Heuristic is insecure.
• First example of ID protocol where Fiat-Shamir
  transform yields insecure signature.