Passive Decryption of Ethereum Peer-to-Peer Traffic

Ethereum, a popular cryptocurrency, utilizes a P2P flood network overlay protocol in order to propagate new transactions and state around the network. As has been shown in previous works[^1][^2], observing the propagation of transactions through the peer-to-peer network layer is often enough to deanonymize users of cryptocurrency networks....

On Linux’s Random Number Generation

I have been asked about the usefulness of security monitoring of entropy levels in the Linux kernel. This calls for some explanation of how random generation works in Linux systems. So, randomness and the Linux kernel. This is an area where there is longstanding confusion, notably among some Linux kernel developers, including Linus Torvalds himself. … Continue reading On Linux’s Random Number Generation

Demystifying AWS’ AssumeRole and sts:ExternalId

Amazon Web Services' AssumeRole operation accepts an optional parameter called "sts:ExternalId" which is intended to mitigate certain types of attacks. However, both the attacks that sts:ExternalId mitigates and how to properly use it are widely misunderstood, resulting in large numbers of vulnerable AWS-based applications. This post aims to describe what std:ExternalId does, when to use … Continue reading Demystifying AWS’ AssumeRole and sts:ExternalId