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{ Category Archives } Security

Checksums, Digital Signatures, and Message Authentication Codes, OH MY!

I recently submitted a bug to the Vim project about its Blowfish encryption not using authentication. Bram Moolenaar, the lead developer of Vim, responded about using checksums and digital signatures. I hope he doesn't mind me using him as an example here, but I want to quote the relevant bits (emphasis mine): The encryption is […]

Bitcoin Mining Rate and Waste

Recently, the Bitcoin mining rate surpassed 1 exahash per second, or 1 quintillion SHA-256 hashes per second. If we do some quick math, we can determine the following: If SHA-1 collisions can be found in 2^65.3 hashes, that's one SHA-1 collision found every 45 seconds. Every combination of bits can be flipped in an 84-bit […]

Encrypted Account Passwords with Vim and GnuPG

Background I've been a long-time KeepassX user, and to be honest, I don't see that changing any time soon. I currently have my password database on an SSH-accessible server, of which I use kpcli as the main client for accessing the db. I use Keepass2Android with SFTP on my phone to get read-only access to […]

Multiple Encryption

I hang out in ##crypto in Freenode, and every now and then, someone will ask about the security of multiple encryption, usually with the context that AES could be broken in the near future. When talking about multiple encryption, they are usually referring to cascade encryption which has the form of: CT = Alg_B(Alg_A(M, key_A), […]

Your GnuPG Private Key

This post is inspired by a discussion in irc:// about Keybase and a blog post by Filippo Valsorda. I was curious just exactly how my private key is encrypted. Turns out, gpg(1) can tell you directly: $ gpg --output /tmp/secret-key.gpg --export-secret-keys 0x22EEE0488086060F $ gpg --list-packets /tmp/secret-key.gpg :secret key packet: version 4, algo 17, created 1095486266, […]

Now Using miniLock

I have been a long proponent of OpenPGP keys for a way to communicate securely. I have used my personal key for signing emails since ~ 2005. I have used my key at dozens and dozens of keysigning parties. I have used my key to store account passwords and credentials with vim(1), Python, and so […]

Do XKCD Passwords Work?

You'll always see comments on web forums, social sites, blog posts, and emails about "XKCD passwords". This is of course referring to the XKCD comic by Randall Munroe describing what he thinks is the best password generator: What no one has bothered asking, is if this actually works. Lorrie Faith Cranor, director of the Carnegie […]

Setting Up A Global VPN Proxy on Android with L2TP/IPSec PSK

In my last post in this short series, I want to discuss how to setup a transparent proxy on your Android phone using the builtin VPN for L2TP. As usual, the same precautions apply here. Don't be stupid with your data, just because you can hide it from your ISP. In general, I'm skeptical of […]

Setting Up A Global Tor Proxy on Android with Orbot

In my last post, I explained how to setup a Global SSH proxy on Android with ConnectBot and ProxyDroid. In this article, I'll do the same thing, but with Orbot. Also, as with the last article, the same precautions apply here. If you're on an untrusted or unknown network, using an encrypted proxy can be […]

Setting Up A Global SSH Proxy on Android with ConnectBot and ProxyDroid

I'm one that takes precautions with my data when on unfamiliar or untrusted networks. While for the most part, I trust TLS to handle my data securely, I find that it doesn't take much effort to setup a transparent proxy on my Android handset, to route all packets through an encrypted proxy. In this case, […]

md5crypt() Explained

Recently, the Password Hashing Competition announced its winner, namely Argon2, as the future of password hashing. It's long since been agreed that using generic-purpose cryptographic hashing algorithms for passwords is not a best practice. This is due to their speed. Cryptographic hashing algorithms are designed to be lighting fast, while also maintaining large margins of […]

The Chaocipher With Playing Cards

As you know, I am a cryptography hobbyist. More specifically, I have an interest in pencil and paper ciphers, also referred to as "hand ciphers" or "field ciphers". Since Bruce Schneier released his Solitaire Cipher for Neal Stephenson's book "Cryptonomicon" (known in the book as "Pontifex"), I have had a real desire to learn hand […]

The Kidekin TRNG Hardware Random Number Generator

Yesterday, I received my Kidekin TRNG hardware random number generator. I was eager to purchase this, because on the Tindie website, the first 2 people to purchase the RNG would get $50 off, making the device $30 total. I quickly ordered one. Hilariously enough, I received a letter from the supplier that I was their […]

Additional Testing Of The rtl-sdr Dongle As A HWRNG

A couple days ago, I put up a post about using the Realtek SDR dongles as a hardware true random number generator. I only tested the randomness of a 512 MB file. I thought this time, I would but a bit more stock into it. In this case, I let it run for a while, […]

Hardware RNG Through an rtl-sdr Dongle

An rtl-sdr dongle allows you to receive radio frequency signals to your computer through a software interface. You can listen to Amateur Radio, watch analog television, listen to FM radio broadcasts, and a number of other things. I have a friend to uses it to monitor power usage at his house. However, I have a […]