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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17:50
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17:50
Finite Automata - What you need to know
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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26:13
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26:13
Shamir's Secret: A PayPal Near-Disaster
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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8:21
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8:21
SLAP and FLOP: Apple Silicon Speculative Execution Attacks
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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15:33
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15:33
Subaru Starlink Security Flaw
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.
A podcast where logic meets lunacy, and graphs guide the way through the madness! Join us as we explore the beautiful intersections of mathematical logic, graph theory, discrete math, computer science, and the quirky chaos of everyday life. From proving theorems to untangling graph traversals, we’ll connect seemingly random dots to create a web of ideas that’s as entertaining as it is enlightening.
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