I'm happy to announce that the first half the bounty here https://www.yours.org/content/06-bch-bounty-for-two-electron-cash-plugins--privacy-and-recurring-pa-bc2fcf227bae has been claimed, this time by cculianu, therefore completing both parts of the original bounty!

Without further ado, go download the plugin here: https://github.com/cculianu/DonateSpareChange/releases

Why use it?

Bitcoin (Cash), with its UTXO model, guarantees a certain level of privacy by the ways of pseudonymous addresses, later enhanced by the widespread use of HD wallets where a separate address is generated for each coin received, ensuring people who transact with you cannot easily know how your other transactions are going just by looking at the blockchain. However, there's a problem with this model, as Satoshi pondered in the whitepaper:

Some linking is still unavoidable with multi-input transactions, which necessarily reveal that their inputs were owned by the same owner. The risk is that if the owner of a key is revealed, linking could reveal other transactions that belonged to the same owner.

In other words, if you pay Alice and get some change back, then pay Bob and get some change back, then later pay Charlie with the two change change coins together, not only will Charlie see your previous history, but Alice and Bob can get a sneak peek at each other's transaction as well, knowing they involve you .

Generally with most wallets, to minimize fees and maintain privacy at the same time they try to spend from just one output in any transaction as much as possible, so this information leaking is minimized. However, when you spend down a coin, you eventually get to a point where the coin is too small to spend on any regular things you like, and have to be combined - making it possible to group the entire chain of transactions with another chain of transactions, and link them back to you to any party who transacted with you. In most wallets, this happens without you even noticing!

Here's where the plugin comes in. The small changes leftover are, well, small anyway. Why not just donate them, just like you throw pennies into the supermarket charity box ?

By sending the change to a donation address by itself, you end the chain without combining it with anything else. Charities have public addresses anyway, when they combine their coins on the single address, nobody's privacy is leaked. You gain privacy, big brother surveillance is frustrated, your chosen charity gets coins. What is not to love?

Keep in mind that I do not claim that this will solve all your privacy needs - far from it, mixers and shuffling will still be needed, privacy is a hard problem. But it's not binary, and anything to frustrate chainalysis while keeping charities up is a good thing! I already do it manually, so I'm very happy that there's now a way everyone can do it too - automatically.

How to use: