Tags: cipher 

Rating: 5.0

Here is the cipher image:

These series of images are traces of a google keyboard when using the "glide typing" method (called "swipe typing" on iphones) of typing on a smartphone keyboard. To solve this, just overlay each image over a google keyboard and figure out the word that must have been spelled with that trace. Let's start with a screenshot of the first image in the cipher.

We can make the white background transparent with https://onlinepngtools.com/create-transparent-png:

Now let's get an image of an android google keyboard, like this one:

Finally, let's overlay the trace over the image of the keyboard. I'm sure you can do this with other applications, but I used Paint 3D. It's easy to line up with the border already given around each trace image.

We can see that there are really only 2 possible words traced: `edilg` and `glide`. It's obvious which one it is. Now we just do the same with all the other images. The only different thing you must do are with the images of 2 dots. Those are special characters. Here is what it looks like overlayed:

We see a dot on the `?123` and in-between the `d` and `f`. If we look at the gboard special characters (which is what you get after pressing `?123`), we see that the underscore (`_`) lands basically in-between the `d` and `f`.

Do the same thing with the very last image and you'll get an exclamation mark (`!`).

After doing all of this you should get the message `glide_typing_is_honestly_the_bomb!`

Original writeup (https://github.com/NihilistPenguin/PatriotCTF2022-Writeups/blob/main/Crypto/Fly.md).