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{ Category Archives } Cryptology

Automated Diceware Passwords

For those unfamiliar, Diceware.com is a way of picking truly random passphrases from a predefined dictionary list of words. The idea is that each word has a 5 digit number attached to it. Each digit in the number holds the values 1-6, in numerical order. So, the first password starts with 11111, then 11112, 11113, […]

Haveged Continued

I noticed that on my machine, my entropy was staying high, then falling off. Then, at what appeared to be some arbitrary point, it would fill back up, in a very periodic manner. This is, of course, after running haveged in the background. Curious, I started looking into it. It took a while to find. […]

Haveged - A True Random Number Generator

I admit that my last post sucked. I've been working on a few things that I want to blog about, but it's going to take time to get all my ducks in a row. So, that post was mostly "filler". Read as "I haven't blogged in a while, and should probably put something up". Sorry. […]

The One-Time Pad Hard Drive

I devised a system to use the one-time pad (OTP) using nothing more than a hard drive. It goes something like this: Meet in person with identical size hard drives. Encrypt the hard drive. File the drive with random keys of incrementing size. Devise an alorithm for using the keys. Unmount the drive. Enjoy the […]

Encrypted ZFS Filesystems On Linux

This is just a quick post about getting a fully kernel-space encrypted ZFS filesystem setup with GNU/Linux, while still keeping all the benefits of what ZFS offers. Rather than using dmcrypt and LUKS, which would bypass a lot of the features ZFS brings to the table, encryptfs is our ticket. The reason this is so […]

High Capacity Color Barcode

I've been reading up on how to actually create physical QR Codes, complete with error correction. It's been very enlightening, and has grown a deeper fascination on the symbology of barcodes in general for me. While I'm not in 100% agreement with how they are currently being used (marketing, mailing lists, coupons, etc.), I do […]

Hand Ciphers: Solitaire Cipher

This hand cipher was invented by cryptographer Bruce Schneier, and requires nothing more than a full 54-card deck of standard playing cards. Here is the basic idea, then we'll get into the details. First, you need a standard 52-card poker deck of playing cards (4 suits, 13 unique cards per suit), with the two jokers. […]

Randomize First, Then Encrypt Your Block Device

This blog post is in continuation of the previous post, where I showed why you should not use ECB when encrypting your data. Well, when putting down an encrypted filesystem, such as LUKS, you've probably been told that you should put random data down on the partition first BEFORE encrypting the disk. Well, this post […]

ECB vs CBC Encryption

This is something you can do on your computer fairly easily, provided you have OpenSSL installed, which I would be willing to bet you do. Take a bitmap image (any image will work fine, I'm just going to use bitmap headers in this example), such as the Ubuntu logo, and encrypt it with AES in […]

Making Sense of Hashed Hosts in ~/.ssh/known_hosts

I don't expect you to follow this post completely, but it's so amazingly cool, I have to blog it. Consider the hashed sections of ~/.ssh/known_hosts file for (recent) OpenSSH clients, not including the public key parts: |1|kFJT5z0x3ndyutgZ4E5pRk+ORBA=|hzXvdYUudo+qK9BGlFWtSAUXlXc= |1|8wo1+FO0hkATPgQZoeNHeIlvAjw=|dt/a9jz9CnLKP72j+Jr8MKMjgEE= |1|pvBQEKEGLnH0RCJr+8Dmqqnvlrs=|fJJvjyG/TmHFnuIX57nDThq/C4M= |1|HKV4DzgDkajXoUHf9B82JBu7J10=|c/K+MdJvWaZeJFs/W7iqhqo0wvE= |1|rtvQhRVnNanQZYkLUMbjoBGNhn0=|0U6a1LUQqLL6P1T2Wji3VWw69pw= |1|0ziSYi4c+xBXGEBZcNN1LMhYUc4=|qRSN5GSPyQi+fmaVz2zNwkmKoy8= |1|6nv6Vpk3AYgICHxJGVgVdsYRuq0=|fBNOIz1l3RW+N61jyDPunKX9n7E= |1|+b4uA+Mq7RHRAFW21qv8aO3rIRs=|1eizMri01IxEKrXquBnwTYP61Ow= |1|BkB0PZu2qtsLID/Ibe/D68gANQU=|qW6uAzcpecOOKNI4zEvngyfpGkI= |1|n+QrRn7QXeAJ5hRe2M8v8IspihE=|EqUxXdSeIF1cl1fQjl5zILebkGY= |1|BOKuKnWojy028tJf9Y671lws0d0=|SuBQJmJZp5JNVYG/rP9yb9ZhJcE= |1|WACsxtodOiM89kf4rNPLgF1CXZ4=|UTccVeLDZJF3wlH8V05XJNlsOBw= |1|o6FFoirXYblM7wBMdeJDYGMPI58=|5jJB7T7itY702ZHHByXtSpGk9SE= The column fields are similar to […]

OpenSSH Best Practices

This post comes from Matt Taggart, who put together a document about the best practices for using OpenSSH. A lot of the points brought up in that document rang the bells of common sense, and are so good, it's worth blogging about in hopes that the points mentioned therein reach as many as possible. I've […]

Convert Text To Base-64 By Hand

When I was a kid, I had this fascination with cryptography. I learned and used, as most kids to, the Caesar cipher first (using my trusty Captain Crunch Decoder Ring), then later learned and used the Affine cipher. It was great for passing notes in class when I was in elementary and secondary education. I […]

Verifying Hashcash Tokens With Mutt

Just five days ago, I blogged about minting Hashcash tokens in Mutt using a Python script (make sure you check that page for any updates to the source if you're using it). Well today, I finished writing my verification script. It takes some additional changes to your ~/.muttrc, which I'll outline here, and it requires […]

Hashcash and Mutt

Introduction I wanted to used Hashcash with Mutt, for nothing more than a curiosity to see if it generates any discussion, and to see if people notice. Further, I'm a big crypto advocate, and while Hashcash isn't exactly crypto, it's highly related to it, and uses it. Regardless, I wanted to see if I could […]

Bitlbee and OTR

I'm actually surprised that I haven't blogged about this before, seeing as though I use it daily. Further, seeing as though I seem to be on a security blogging trip, it only seems fitting to discuss OTR support in Bitlbee now. OTR, or Off-The-Record messaging is the ability to have encrypted and authenticated communication with […]

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