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{ Category Archives } Cryptology

Heartbleed And Your Passwords

Recently it was discovered that OpenSSL contained a pretty massive security hole that allowed simple TLS clients to retrieve plain text information from a TLS-protected server using the TLS Heartbeat. The advisory is CVE-2014-0160. This has to be one of the most dangerous security vulnerabilities to hit the Internet in a decade. More information can […]

The Reality of SHA1

Many people don't understand crypto. That's okay. I don't either. But, I do get math, and I want to show you something SIGNIFICANT that affects your everyday habits online. It's been demonstrated that MD5 is broken. It's now trivial to find what are called "collisions". This is where two completely different inputs hash to the […]

SCALE 12x PGP Keysigning Party

This year, at SCALE 12x, I'll be hosting the PGP keysigning party. What is a keysigning party, and why should you attend? Maybe this will clear things up. What is a keysigning party? A PGP keysigning party is an event where PGP users meet together to exchange identity information and PGP fingerprints. Typically, at a […]

The Drunken Bishop Cipher Is Weak

Well, it turns out that my own hand cipher is incredibly weak. When I initially started designing it, using a chessboard felt a lot like an S-box lookup. There has been a great deal of research into S-boxes since the release of DES, and many ciphers today use them. What plagued me from day one, […]

The Drunken Bishop Cipher

Background Ever since learning Bruce Schneier's Solitaire Cipher, I was interested in creating a hand cipher of my own. Unfortunately, I'm just an amateur cryptographer, and a lousy one at that. So I didn't have any confidence in creating my own hand cipher. However, after learning about the SSH ASCII art, and the drunken bishop, […]

Sufficient Paranoia

With all the recent revelations about the NSA violating United States citizen's 4th amendment rights with their warrantless wiretapping, and now the news of Silk Road being taken down, and the NSA trying to crack Tor (it won't happen- I trust the mathematics), I thought now would be a good time to discuss the concept […]

OpenSSH Keys and The Drunken Bishop

Introduction Have you ever wondered what the "randomart" or "visual fingerprint" is all about when creating OpenSSH keys or connecting to OpenSSH servers? Surely, you've seen them. When generating a key on OpenSSH version 5.1 or later, you will see something like this: $ ssh-keygen -f test-rsa Generating public/private rsa key pair. Enter passphrase (empty […]

Strengthen Your Private Encrypted SSH Keys

Recently, on Hacker News, a post came through about improving the security of your encrypted private OpenSSH keys. I want to re-blog that post here (I'm actually jealous he blogged it first), in my own words, and provide a script at the end that will automate the process for you. First off, Martin goes into […]

Password Attacks, Part III- The Combination Attack

Introduction It's important to understand that most of the password attacks to offline databases where only hashes are stored are extensions of either the brute force attack or the dictionary attack, or a hybrid combination of both. There isn't really anything new outside of those two basic attacks. The combination attack is one such attack […]

Password Attacks, Part II - The Dictionary Attack

Introduction Before we start delving into the obscure attacks, it probably makes the most sense to get introduced to the most common attacks. The dictionary attack is one such attack. Previously we talked about the brute force attack, which is highly ineffective, and exceptionally slow and expensive to maintain. Here, we'll introduce a much more […]

Password Attacks, Part I - The Brute Force Attack

Introduction For those who follow my blog know I have blogged about password security in the past. No matter how you spin it, no matter how you argue it, no matter what your opinions are on password security. If you don't think entropy matters, think again. Entropy is everything. Now, I've blogged about entropy from […]

Create Your Own Graphical Web Of Trust- Updated

A couple years ago, I wrote about how you can create a graphical representation of your OpenPGP Web of Trust. It's funny how I've been keeping mine up-to-date for these past couple years as I attend keysigning parties, without really thinking about what it looks like. Well, I recently returned from the SCaLE 11x conference, […]

Announcing Hundun

Per my last post, I decided to setup an entropy server that the community could use. So, I've done just that. That server uses 5 entropy keys from Simtec Electronics in the U.K. as its hardware true random number generators. It hands out high quality randomness for the most critical cryptographic applications. The purpose, is […]

The Entropy Server

With my last post about the entropy key hardware true random number generator (TRNG), I was curious if I could set this up as a server. Basically, bind to a port that spits out true random bits over the internet, and allow clients to connect to it to fill their own entropy pools. One of […]

The Entropy Key

Recently, I purchased 5 entropy keys from http://entropykey.co.uk. They are hardware true random number generators using reverse bias P-N junctions. Basically, they time when electrons jump a depeltion zone in the junction, where a voltage is applied to the point of near breakdown. Basically, taking advantage of the random characteristics of quantum mechanics. There are […]

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