One of my first vivid memories when it comes to having fun while programming definitely contains me implementing RC4 encryption in QBasic. Algorithm was perfect. It worked on per-byte text, was simple enough to have at least basic understanding what the heck was happening, and it gave me a bit of “el bandito” feeling as algorithm was leaked. Going over RC4 encouraged me to reinvent the wheel and was a direct cause of my love into creating own encryption algorithms. And I’ve created quite a few…

In time I learned a bit more about encryption. Or at least enough to understand why “rolling your own” is generally a bad idea. With time my beloved RC4 got its ass kicked by cryptoanalysis to be finally deprecated in 2015. My focus meantime went toward block algorithms, most notably Twofish and later AES version of Rijndael. My mind decided to go block cipher route but my heart still longed for good old stream cipher times.

As someone following crypto-world as a hobby, I was surprised I missed a whole stream cipher competition – eSTREAM. At this time it’s already an ancient news but results of that competition are still available in the form of 4 secure software stream ciphers: HC-128, Rabbit, Salsa20/12, and SOSEMANUK. All these eSTREAM finalists are still secure, completely free, and really nostalgia inducing for those with a soft spot for stream ciphers.

One that immediately drew my attention was Rabbit. As name suggests, this one was really fast. Additionally, it has quite understandable method of operation, uses no “exotic” operations, it has a reasonably small state (513 bits), and it’s specified in RFC4503. The only thing I couldn’t find was a C# implementation wrapping it into a SymmetricAlgorithm so it can be easily used with CryptoStream. Well, now there’s one…

If you want to use the Rabbit from C#, take a look at my RabbitManaged class. It derives from SymmetricAlgorithm and exposes ICryptoTransform interface so it can be used with CryptoStream. While it uses 128-bit blocks internally, it also allows usage without padding (i.e. more like a traditional stream algorithm). It also allows for all standard paddings.

Considering wide prevalence of AES, its usage will be limited at best but I believe into not having all eggs in one basket and you might find usage for it still. But damn, it was fun to implement this little gem.

PS: For nostalgia, I also have a SymmetricAlgorithm implementation of RC4.

My problem started with a cat. She loves enforcing my laptop breaks and having some laptop time herself. Whenever that happens, I lock my laptop and let her be for 5 minutes. Without fail she’ll manage to turn off wireless and enable the darn Windows Narrator. And no, turning off the Narrator shortcut doesn’t help.

Issue here is that lock screen works under completely different environment and permanently disabling narrator shortcut for your user will do nothing. No, solving this requires a bit more interaction and the easiest way I found is through registry editing.

To turn off the Narrator, there is a well documented WinEnterLaunchEnabled registry value. For our user we can find this at HKEY_CURRENT_USER\Software\Microsoft\Narrator\NoRoam but for logon user this hides at HKEY_USERS\S-1-5-18\Software\Microsoft\Narrator\NoRoam. Setting this DWORD value to 0 sorts the issue even without going for restart.

However, since my cat also plays with touchpad, I decided to remove the whole Ease of Access portion to ensure erroneous touchpad movements as cat lays down cannot turn anything on. For this we need the BrandingNeutral value. This can be found at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Embedded\EmbeddedLogon. Setting DWORD value to 8 followed by a restart sorts out that issue.

Those full of trust can download registry file with these settings here and import them automatically while others can do the registry changes manually. In either case Windows 10 will become a bit more cat friendly.

As a time connoisseur, I really get really pissed off when my phone’s time is off by a second or two. Considering phone receives time from the radio network, one would expect this not to happen. However, for some reason, it seems no USA network provider actually cares to have their radio time straight. The solution to this problem would be using an NTP server instead of the time provided by the network. However, with an Android devices that’s not as straightforward as one would expect. But it is possible…

Before starting anything, we first need to turn on Developer Options (usually tapping Build Number 7 times). Once this is enabled, we need to enable USB Debugging (Settings > System > Advanced > Developer Options > USB debugging). With this done, we can finally download Platform Tools and check if our device is visible:

Terminal  Copy
adb devices
List of devices attached
0A281JCCBA0317  device

Once connectivity is tested, we can immediately go onto setting the NTP server followed by a reboot:

Terminal  Copy
adb shell settings put global ntp_server time.medo64.com
adb reboot

Once device has rebooted we can check the value:

Terminal  Copy
adb shell settings get global ntp_server 
time.medo64.com

And that’s it. Now your device will use the defined time server instead of the unreliable network time.