Many people, including myself, who participate in the cryptocurrency space enjoy using and contributing to open source
projects. I'm sure most of you have heard this term and it's turned into quite a buzzword unfortunately. But open
source is just what it sounds like actually. It just means the source code is made available to the public usually
via git or GitHub. This means anyone can inspect, modify, redistribute or fork the software in any public
repository. It's not quite that simple and there are different types of licensing such as MIT License, GPL, BSD,
Apache license 2.0, and Mozilla public license. To keep it simple though when projects are developed open
source no one company person or entity owns, makes or distributes the software. Things like Linux, Firefox, and
Git are open source and along with many more make up a large part of the internet. Keep in mind that open
source doesn't inherently mean good.

So what about software in the crypto industry? It plays a massive role! Bitcoin itself is open source and the
bitcoin core reference client has over 15,000 contributions! Not to mention ethereum and all the coins that are forks of bitcoin and like ltc and bch.

What I want to bring light to though is crypto currency wallets. First there are a lot of misconceptions about wallets.
They don't actually hold your crypto but store your private keys which prove you own the crypto on the
blockchain. Cryptocurrency wallets could be considered one of the most important applications some people use
and while there are some good open source wallets it seems like many are not and also some debate as to
which ones are completely open source or not. Trust wallet being a good example, founded by Viktor Radchenko
and acquired by Binance in 2017. Once completely open source now only its core code is and the mobile
application isn't. This is a growing trend it seems. Meta mask, a once completely open source project changed
its licensing agreement in 2020 limiting any commercial project who leverages their code to have fewer than
10,000 users. Another popular one exodus while it has some pieces of the wallets source code is open source
the majority isn't. Keep in mind as I said earlier closed source don't inherently mean bad. I personally use all
these mentioned but have varying levels of trust in them and have different uses for them.

There are tons of great options for cryptocurrency wallets these days and they don’t HAVE to be open source
but if possible it's nice to know what's in the code and being an advocate for (F.O.S.S.) Free and open source
software is something I think is overlooked when it comes to wallets. Hopefully as the years go by more
completely open source multi chain wallets with good features are developed but until then listed below are
some of the more popular completely open source ones that I like as well as a very helpful website to help you
get a better insight into wallet security here. 

1. Mycelium
A well known reproducible bitcoin wallet hyper focused on security code can be viewed here
https://github.com/mycelium-com/wallet-android

2. Unstoppable wallet
Somewhat newer wallet supports bitcoin, ethereum, avalanche, solana and more. There seems to be some
debate over the code though. While wallet scrutiny couldn't reproduce the wallet the full code is listed here
https://github.com/horizontalsystems/unstoppable-wallet-android

3. Airgap
Airgap is an exceptional wallet where everything is stored offline on a dedicated device with lots of features.
Really interesting one and worth looking into. Reproducible and supports bitcoin, ethereum, cosmos, kusama, polkadot and more. Full code can be viewed here https://github.com/airgap-it/airgap-wallet

Regardless of the wallet you choose, always make sure to properly store and protect your seed phrase,
never revealing it to anyone. Thanks for reading.