Categories
Cryptography Software Security Technology

Dead Ends in Cryptanalysis #2: Timing Side-Channels

Previously on Dead Ends in Cryptanalysis, we talked about length-extension attacks and precisely why modern hash functions like SHA-3 and BLAKE2 aren’t susceptible. The art and science of side-channel cryptanalysis is one of the subjects I’m deeply fascinated by, and it’s something you’ll hear me yap about a lot on this blog in the future. […]

Categories
Cryptography Software Security

Cryptography Interface Design is a Security Concern

Cryptographers and cryptography engineers love to talk about the latest attacks and how to mitigate them. LadderLeak breaks ECDSA with less than 1 bit of nonce leakage? Raccoon attack brings the Hidden Number attack to finite field Diffie-Hellman in TLS? And while this sort of research is important and fun, most software developers have much […]

Categories
Badness Cryptography Software Security Technology Vulnerability

On The Toxicity of Zed A. Shaw

Boycott Zed Shaw’s writing. (With bonus zero-days in his work.)

Categories
Cryptography Software Security

Please Stop Encrypting with RSA Directly

RSA is for encrypting symmetric keys, not entire messages. Pass it on.

Categories
Badness Online Privacy Technology Vulnerability

Masks Off for TheDonald.win

The server for thedonald.win is hosted at 167.114.145.140. Read on to learn how I discovered this.

Categories
Cryptography Software Security

The Subtle Hazards of Real-World Cryptography

Imagine you’re a software developer, and you need to authenticate users based on a username and password. If you’re well-read on the industry standard best practices, you’ll probably elect to use something like bcrypt, scrypt, Argon2id, or PBKDF2. (If you thought to use something else, you’re almost certainly doing it wrong.) Let’s say, due to […]

Categories
Cryptography Software Security

Dead Ends in Cryptanalysis #1: Length Extension Attacks

This is the first entry in a (potentially infinite) series of dead end roads in the field of cryptanalysis. Cryptography engineering is one of many specialties within the wider field of security engineering. Security engineering is a discipline that chiefly concerns itself with studying how systems fail in order to build better systems–ones that are […]

Categories
Badness Software Security Vulnerability

EduTech Spyware is Still Spyware: Proctorio Edition

Spyware written for educational institutions to flex their muscles of control over students and their families when learning from their home computer is still, categorically, spyware. Depending on your persuasion, the previous sentence sounds like either needless pedantry, or it reads like tautology. But we need to be clear on our terms. Educational spyware is […]

Categories
Cryptography Software Security

Soatok’s Guide to Side-Channel Attacks

If you’re ever tasked with implementing a cryptography feature–whether a high-level protocol or a low-level primitive–you will have to take special care to ensure you’re not leaking secret information through side-channels. The descriptions of algorithms you learn in a classroom or textbook are not sufficient for real-world use. (Yes, that means your toy RSA implementation […]

Categories
Cryptocurrency Vulnerability

Kerlissions – Trivial Collisions in Iota’s Hash Function (Kerl)

Historical Context of Iota’s Hash Functions Once upon a time, researchers discovered that the hash function used within the Iota cryptocurrency (Curl-P), was vulnerable to practical collisions. When pressed about this, the Iota Foundation said the following: In response to this research, the Iota developers threatened to sue the researchers. Iota replaced Curl-P-27 with a […]

Categories
Cryptography Software Security

GNU: A Heuristic for Bad Cryptography

If you see the letters GNU in a systems design, and that system intersects with cryptography, I can almost guarantee that it will be badly designed to an alarming degree. This is as true of GnuPG (and PGP in general) as it is of designs like the proposed GNU Name System (IETF draft) and cryptographic […]

Categories
Cryptography Vulnerability

Learning from LadderLeak: Is ECDSA Broken?

A paper was published on the IACR’s ePrint archive yesterday, titled LadderLeak: Breaking ECDSA With Less Than One Bit of Nonce Leakage. The ensuing discussion on /r/crypto led to several interesting questions that I thought would be worth capturing and answering in detail. What’s Significant About the LadderLeak Paper? This is best summarized by Table […]

Categories
Furry Fandom Online Privacy Vulnerability

How to De-Anonymize Scam/Knock-off Sites Hiding Behind CloudFlare

Update (2021-01-09): There’s a newer blog post that covers different CloudFlare deanonymization techniques (with a real world case study). Furry Twitter is currently abuzz about a new site selling knock-off fursuits and illegally using photos from the owners of the actual fursuits without permission. Understandably, the photographers and fursuiters whose work was ripped off by […]

Categories
Humor Software Security Vulnerability

Why Server-Side Input Validation Matters

Update (2020-04-29): Twitter has fixed their oversight. Anyone who set their custom gender to a long volume of text, should still have it set to a long volume of text. The original article follows after the separator. I was recently made aware of a change to Twitter, which exposes a new Gender field. If you’ve […]

Categories
Software Security

“Source Code Leak” is Effectively Meaningless to Endpoint Security

There are two news stories today. Unfortunately, some people have difficulty uncoupling the two. The Team Fortress 2 Source Code has been leaked. Hackers discovered a Remote Code Execution exploit. The second point is something to be concerned about. RCE is game over. The existence of an unpatched RCE vulnerability, with public exploits, is sufficient […]