Categories
Cryptography

Understanding HKDF

HKDF has poorly-understood subtleties. Let’s explore them in detail.

Categories
Cryptography

Programmers Don’t Understand Hash Functions

Programmers don’t understand hash functions, and I can demonstrate this to most of the people that will read this with a single observation: When you saw the words “hash function” in the title, you might have assumed this was going to be a blog post about password storage. (Passwords are the most common knee-jerk reaction […]

Categories
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

Putting the “Fun” in “Hash Function”

There are several different methods for securely hashing a password server-side for storage and future authentication. The most common one (a.k.a. the one that FIPS allows you to use, if compliance matters for you) is called PBKDF2. It stands for Password-Based Key Derivation Function #2. Why #2? It’s got nothing to do with pencils. There […]