Categories
Cryptography

Database Cryptography Fur the Rest of Us

An introduction to database cryptography.

Categories
Cryptography Software Security Vulnerability

Threema: Three Strikes, You’re Out

Threema boldly claims to be more secure than Signal. Does this hold up to scrutiny?

Categories
Bullshit Cryptography

Crackpot Cryptography and Security Theater

Tales from the Crypt[ography].

Categories
Cryptography Software Security

Please Stop Encrypting with RSA Directly

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

Categories
Cryptography

Block Cipher Structures: Ranked

An opinionated curation of different classes of block ciphers, ranked by an opinionated furry.

Categories
Cryptography

Cryptographic Wear-Out for Symmetric Encryption

As we look upon the sunset of a remarkably tiresome year, I thought it would be appropriate to talk about cryptographic wear-out. What is cryptographic wear-out? It’s the threshold when you’ve used the same key to encrypt so much data that you should probably switch to a new key before you encrypt any more. Otherwise, […]

Categories
Cryptography

Designing New Cryptography for Non-Standard Threat Models

Since the IETF’s CFRG decided to recommend OPAQUE as a next-generation Password Authenticated Key Exchange, there has been a lot of buzz in the cryptography community about committing authenticated encryption (known to the more academically inclined as Random Key Robustness), because OPAQUE requires an RKR-secure AE scheme. Random Key Robustness is a property that some […]

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
Cryptography

Comparison of Symmetric Encryption Methods

There seems to be a lot of interest among software developers in the various cryptographic building blocks (block ciphers, hash functions, etc.), and more specifically how they stack up against each other. Today, we’re going to look at how some symmetric encryption methods stack up against each other. If you’re just looking for a short […]

Categories
Cryptography

Why AES-GCM Sucks

If you’re reading this wondering if you should stop using AES-GCM in some standard protocol (TLS 1.3), the short answer is “No, you’re fine”. I specialize in secure implementations of cryptography, and my years of experience in this field have led me to dislike AES-GCM. This post is about why I dislike AES-GCM’s design, not […]