Yes, you heard me right. Compressed public keys are a thing, and they can save us all some precious storage space on our hard drives (or whatever device you use for storing your bitcoins).

Now, before we dive into the technical details of how this works, lets first talk about why compressed public keys exist in the first place. Well, it turns out that regular public keys can be pretty ***** long like 65 bytes or so. And if you have a lot of them (which is not uncommon), they can take up quite a bit of space on your computers hard drive.

But with compressed public keys, we can squeeze those same 65 bytes down to just 33 bytes! That might not sound like much, but trust me it adds up over time. Especially if you have thousands or even millions of public keys stored on your device.

So how do these magical compressed public keys work? Well, lets start with a regular public key (which well call P). This is just a big ol number that represents the owners address in Bitcoin. And if you want to send someone bitcoins, all you have to do is use their public key as your destination address.

But heres where things get interesting: instead of using the full 65-byte version of P (which well call P_full), we can actually compress it down into a smaller form called P_compressed. And this compressed version is what youll typically see when someone shares their Bitcoin address with you because it takes up less space and is easier to share over email or social media.

So how do we convert P_full into P_compressed? Well, first we need to calculate a special value called the y-coordinate of P (which well call y). And this can be done using some fancy math that involves things like elliptic curves and modular arithmetic.

In fact, the whole process of compressing public keys is actually pretty simple once you get the hang of it. And with a little bit of practice (and maybe some help from your favorite cryptography textbook), youll be able to do it in no time at all.

It might not sound like much, but trust me when I say that this is one of the most important innovations in crypto history (at least as far as storage space goes). And if youre interested in learning more about how these magical little numbers work, be sure to check out some of our other articles on the subject. Until next time!