Tagcryptography
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Understanding Quantum Cryptography
My educational explainer on quantum cryptography, walking through the BB84 quantum key distribution scheme — how photon polarization and the Heisenberg uncertainty principle secure a key exchange and expose eavesdroppers — and how it contrasts with post-quantum cryptography.
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Demystifying Cryptography
A Crypto 101 tour for the curious: what cryptography is, its goals, the anatomy of a secure connection, and the intuition behind Diffie-Hellman key exchange (with a live interactive demo of two parties agreeing on a shared key over an open wire) and the Caesar cipher.
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Introduction to Supersingular Isogeny Diffie-Hellman
An approachable introduction to Supersingular Isogeny Diffie-Hellman (SIDH) — one of the few post-quantum key exchanges built on elliptic curves — written for an Elliptic Curve Cryptography course: its motivation, the math you need (isogenies, the j-invariant, supersingular curves), the key exchange itself, and Costello et al.'s recommended parameters. Rebuilt from the original LaTeX, led in by the post's own blurb.
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Survey of Cryptographic Implementations and Vulnerabilities on Passive RFID Devices
A 20-page survey paper (UCSB) on the cryptography of passive RFID tags — system and adversary models, the attack landscape, the famous Mifare and DST breaks, and mitigation strategies — rebuilt from the original LaTeX, led in by the post's own plain-English "quick version."
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Calculating Nonlinearity of Boolean Functions with Walsh-Hadamard Transform
A short cryptography paper (UCSB) on what nonlinearity means for boolean functions and how to measure it with the Walsh-Hadamard transform — rebuilt from the original LaTeX with a live calculator: flip an 8-bit truth table and watch its Walsh spectrum and nonlinearity recompute.
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WWII and Computers
An old IB History paper asking whether modern electronic computers were built for war or merely re-purposed for it, plus a look at their wartime origins.
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