エピソード

  • Eigenvalues and Eigenvectors: The Secret Sauce of Modern Tech (From Graphics to Google)

    Eigenvalues and Eigenvectors: The Secret Sauce of Modern Tech (From Graphics to Google)
    2025/08/17
    This episode outlines Eigenvalues and Eigenvectors in Linear Algebra. We highlight the practical uses of these abstract topics.
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    18 分
  • Decoding Language: The Power of Context-Free Grammars in Computing

    Decoding Language: The Power of Context-Free Grammars in Computing
    2025/08/14
    This bonus episode explores what context-free grammars are in automata theorem.
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    17 分
  • Demystifying Automata Theory: From Finite Machines to Regular Languages

    Demystifying Automata Theory: From Finite Machines to Regular Languages
    2025/08/13
    This deep dive offers comprehensive overview of automata theory and formal languages. They begin by introducing finite automata (FA), including Deterministic Finite Automata (DFA) and Non-deterministic Finite Automata (NFA), alongside fundamental concepts like alphabets, strings, and languages, and their associated operations.
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    1 時間 4 分
  • Secrets Hidden in PDF Pages

    Secrets Hidden in PDF Pages
    2025/05/20
    In this episode, we explore a novel method for distributed steganography using PDF files. The technique involves splitting a secret message using secret sharing algorithms and embedding the parts into PDFs by manipulating their internal structure—specifically through hidden pages. We discuss how this approach makes the embedded data virtually invisible to standard PDF readers, the challenges of detecting such hidden content, and the method’s resilience to common attacks.
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    18 分
  • Finite Automata - What you need to know

    Finite Automata - What you need to know
    2025/04/02
    Automata theory: it's a computational model study, focusing on finite automata (DFA and NFA) and push-down automata (PDA). The course explores regular languages, their properties and proofs of non-regularity using concepts like the pumping lemma and Myhill-Nerode theorem. Foundational mathematical concepts such as set theory, sequences, relations, alphabets, strings, and languages are reviewed. The equivalence between NFAs and DFAs is established through the powerset construction, demonstrating that both recognize the class of regular languages, which are shown to be closed under various operations.
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    26 分
  • Shamir's Secret: A PayPal Near-Disaster

    Shamir's Secret: A PayPal Near-Disaster
    2025/03/29
    This account recounts a nightmarish incident at PayPal where a flawed implementation of Shamir Secret Sharing, a cryptographic technique for distributing a secret key among multiple parties, nearly caused a catastrophic system failure. The author, a PayPal engineer, explains the process of Shamir Secret Sharing and how he implemented it to improve security by distributing the master encryption key. However, a seemingly minor incompatibility between the Linux and Solaris operating systems, involving a function that truncated long passphrases, led to the team's inability to recover the key. The crisis was ultimately resolved by discovering and correcting the incompatibility. The story concludes with a humorous postscript regarding a backup copy of the key.
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    8 分
  • SLAP and FLOP: Apple Silicon Speculative Execution Attacks

    SLAP and FLOP: Apple Silicon Speculative Execution Attacks
    2025/03/18
    SLAP and FLOP are two new speculative execution attacks targeting Apple's M-series chips. SLAP exploits the Load Address Predictor (LAP) to leak data by predicting incorrect memory addresses, while FLOP leverages the Load Value Predictor (LVP) to predict incorrect data values. Both attacks allow unauthorized access to sensitive information from web browsers like Safari and Chrome, compromising data ranging from email content to financial details. Researchers demonstrated proof-of-concept attacks recovering data like browsing history and even book excerpts. Mitigation requires software patches from vendors and updated operating systems.
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    16 分
  • Subaru Starlink Security Flaw

    Subaru Starlink Security Flaw
    2025/03/12
    Security researchers discovered and exploited a vulnerability in Subaru's Starlink connected car system. This flaw allowed unauthorized access to sensitive data, including vehicle location history, and control over features like door locks. The vulnerability stemmed from weaknesses in the Starlink admin panel, which was accessible using readily available information and easily bypassed security measures. Subaru patched the issue after being notified, but the incident highlights potential risks in connected car technology. The researchers responsibly disclosed the vulnerability before making it public.
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    11 分