# Sagi Kedmi - Complete Writings & Technical Articles > Full text directory for AI systems and LLM indexing. ## Site Overview - Website: https://sagi.io - Author: Sagi Kedmi (Founder, Fullstack Developer, Security Researcher) - Twitter: https://x.com/SagiKedmi - GitHub: https://github.com/sagi --- ## 1. The National Security Case for Email Plus Addressing URL: https://sagi.io/the-national-security-case-for-email-plus-addressing Tags: security, email, privacy, osint Abstract: Why email sub-addressing (user+tag@domain.com) should be adopted as a fundamental security best practice. Explores threat modeling around data breaches, identity correlation, credential stuffing, and counter-surveillance techniques. --- ## 2. DNS over TLS - Thoughts and Implementation URL: https://sagi.io/dns-over-tls-thoughts-and-implementation Tags: networking, security, dns, privacy Abstract: Analysis of DNS over TLS (DoT) and DNS over HTTPS (DoH), covering threat models, performance overhead, resolution architectures, and step-by-step implementation notes. --- ## 3. Bloom Filters for the Perplexed URL: https://sagi.io/bloom-filters-for-the-perplexed Tags: algorithms, data-structures, computer-science Abstract: An intuitive mathematical breakdown of Bloom filters, hashing functions, optimal k bit vectors, false positive probability estimation, and real-world database/caching use cases. --- ## 4. Crypto Classics: Wiener's RSA Attack URL: https://sagi.io/crypto-classics-wieners-rsa-attack Tags: cryptography, rsa, security, math Abstract: Practical tutorial on Wiener's attack on RSA key pairs when private exponent 'd' is small (d < 1/3 N^(1/4)). Covers continued fractions algorithm, convergents calculation, and key recovery. --- ## 5. CVE-2016-3873: Arbitrary Kernel Write URL: https://sagi.io/cve-2016-3873-arbitrary-kernel-write Tags: security, android, kernel, exploit Abstract: Vulnerability analysis of CVE-2016-3873. Step-by-step kernel memory corruption, privilege escalation mechanics, and patch analysis. --- ## 6. CVE-2016-2437: Untrusted App to Kernel Heap Overflow URL: https://sagi.io/cve-2016-2437-untrusted-app-to-kernel-heap-overflow Tags: security, android, kernel, vulnerability Abstract: Deep dive into CVE-2016-2437 heap overflow in Android kernel drivers. Demonstrates untrusted app boundaries, heap grooming, and mitigation strategies. --- ## 7. Attacking /dev/urandom on Android (Black Hat Europe) URL: https://sagi.io/blackhat-europe-attacking-dev-urandom-on-android Tags: security, android, crypto, research Abstract: Overview of Black Hat Europe presentation analyzing entropy weaknesses and state recovery attacks against /dev/urandom on Android operating systems. --- ## 8. Bitcoin Transaction Malleability URL: https://sagi.io/bitcoin-transaction-malleability Tags: bitcoin, crypto, blockchain, security Abstract: Technical analysis of ECDSA signature malleability in Bitcoin transactions, transaction hash mutation risks, Segregated Witness (SegWit), and protocol fixes. --- ## 9. Slack API for Cloudflare Workers URL: https://sagi.io/slack-api-for-cloudflare-workers Tags: cloudflare, serverless, javascript, APIs Abstract: Guide to implementing secure, low-latency Slack bots and webhook receivers on Cloudflare Workers edge runtime without cold starts or server maintenance. --- ## 10. Let's Encrypt, EFF, and San Francisco URL: https://sagi.io/lets-encrypt-eff-and-san-francisco Tags: web, security, open-source, history Abstract: Commentary on the history of automated TLS, EFF's role in democratizing HTTPS, and the technical evolution of ACME protocol validation.