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Security & Privacy

The most popular blog posts about security & privacy on Hacker News. 312 posts.

2021
248

Cryptography behind the top cryptocurrencies

This table is based on research at Nash for work expanding our MPC protocol to secure wallets on new blockchains. We took a snapshot of rankings by market cap in early February 2021. In summary, 74 coins use ECDSA and the secp256k1 curve, including Bitcoin, Ethereum, and 48 ERC20 tokens. 10 coins use EdDSA and…

251

OpenBSD's Pledge and Unveil from Python

Years ago, OpenBSD gained two new security system calls, pledge(2) (originally tame(2) ) and unveil . In both, an application surrenders capabilities at run-time. The idea is to perform initialization like usual, then drop capabilities before handling untrusted input, limiting unwanted side effects. This feature is…

252

How I accidentally took down GitHub Actions (2019)

Last December, I was invited to a private bug bounty program to test a beta version of GitHub Actions. GitHub Actions is a workflow automation tool integrated with GitHub. One common use case of GitHub Actions is for CI builds – a project can fairly easily start up a Docker container every time they push a commit…

256

Imaging mounted disk volumes under duress

Backups are critical. If you are lucky and organised you have a set of useful backup primitives, such as Point in Time snapshots on your Infrastructure As A Service (IaaS), your disk array controller, or volume manager. However there always seems to be some critical machine in my life that does not fall into these…

262

How to exfiltrate code from Bitbucket

Every year or so, something compels me to start over with a fresh OS image. Most recently, that something was an unfortunate water bottle incident. Once again, I need to pull down my digital life from the internet. The code and assets for this blog currently live in a 500 MB Git repository, which was hosted on…

268

No U PNP

Previously on Deep Space Nine, we discussed (read: I complained about) the short life and quick death of DLNA. On the way, I mentioned DLNA's dependence on UPnP as an underlying autoconfiguration protocol. Let's talk a bit more about UPnP, because it's 1) an interesting protocol, 2) widely misunderstood, and 3)…