Bitcoin Forum

I've been a BTC holder for about a year and a half but I'm such a miser that I've never spent any of it.  An online shop I want to place an order with accepts BTC so I'm ready to take the plunge.  I'm thinking an Android wallet with a small balance makes sense.  Any recommendations for that software?

I also don't want everyone I spend BTC with to know my main account's balance.  What is the best way to prevent that from happening?

Not sure as far as Android software, but as for the second question, use a mixer service or something like BlockChain's sharedcoin service.

If i didn't want the people i was buying from to know my main balance then i would send the coin to my address on an exchange then make payment from there.

The andriod question i do not know but would like to know so if you find something could you post here with an update please, thank you.

Here you go => https://www.darkwallet.is

I recommend using mycelium. It's really easy to setup on your phone and works like a dream. I use mulitbit on my PC and every so often I send the required funds through to my mycelium account.
Once you have done it once it's a doddle every time.

I installed Mycelium and it looks fine but then I found the Blockchain Android app:

https://blockchain.info/wallet/android-app

So if I want to use Blockchain's Shared Coin to pay someone without linking the payment to my main wallet (and I don't want to import my main wallet's private key into a Blockchain account), I should send funds from my main wallet to my Blockchain account and then use Shared Coin to send those funds from my Blockchain account to the final recipient?

Just use a mixer, but do make sure the final amount reaching is the right value.

Or I could set up a Blockchain account on blockchain.info, send BTC from my main wallet to there, and then use Shared Coin to send BTC from Blockchain to another account (Blockchain, Mycelium, etc) and use that to pay people so I don't have to use Shared Coin every time I want to pay someone.  That might be better because I can't find Shared Coin in the Blockchain Android app.

Use a different address each time so you dont store btc in the same address.

Don't do it. Blockchain.info's web wallet works quite well, but their Android app is a complete distaster. Mycelium is much, MUCH better.

+1. Recently lost 1BTC due to blockchain.info's android app. For some reason, I think after an update,  it no longer accepted my PIn or password. Well, it accepts the pin, which should unlock the password, but then says the password is incorrect. No amount of reentering the pw solves it. The email backup that I thought I made when I set it up, was never sent, although that could have been user error.

What would the workflow be like to accomplish that?

By simply using a HD wallet, like Mycelium. It takes care of everything. You have to make a backup once (writing 12 words on a piece of paper, but that in a safe) and from that point on, any current and future addresses (and their private keys) can always be restored. For every incoming or outgoing transaction, it will automatically switch to a new address. No user involvement required whatsoever. Really, it doesn't get easier than that.

Is it really that easy?  As long as I use Mycelium (or another HD wallet), I can send and receive BTC and automatically no one will be able to link any 2 transactions I've made?

I have used many android btc wallets,

Green Address- it's not bad but can be a bit slow.
Mycelium- Good wallet and very easy to use for anyome.
Blockchain- Used to be good but just too many problems, heaps of blockchain hacked posts, would not recommend.
Coinbase- East to use, great for beginners and very good security. Just remember they have your private keys so not all people would agree to use it.
Wallet32- The best HD wallet for me, very fast and i have had no problems at all.

These wallets are only good for holding a small amount of coins for spending, due to being online walles and anything online can be hacked.
If your holding anything above $50 worth take it offline and get that btc into a paper or hardware wallet.

Just use Bitcoin Wallet or Mycelium. Transfer small amount from your cold wallet to the apps and then begin spend from there. Shouldn't be much of a hassle as I also did the same.

risk is that when your phone is lost or damaged and had to reinstall

Can anyone confirm this?  None of the addresses can be derived by any of the other addresses?  If that really is the case then my search is over.

This "risk" is very easy to mitigate, especially with Mycelium. It has an excellent backup procedure, very easy, and 100% fool proof. You write down the backup sentence *once*, and you can restore your wallet forever, on any device. Even new private keys you generate in the future. Try it. Really, it works.

Addresses are linked when they are inputs in the same transaction. This is an issue for every wallet.

No, not entirely. Old, simplistic wallets use one address for multiple transactions, both sending and receiving. This is obviously bad for your privacy (and somewhat bad for other, more technical reasons as well).

HD wallets do this:

You have some coins on address A. When spending coins, you send them to merchant X, and the change (leftover) goes to a new address B. When spending coins the next time, you send them to merchant Y, and the change goes to a new address C. And so on. New HD Wallet addresses A, B, C, etc are generated on the fly upon every transaction (incoming as well as outgoing).

So, they are only linked to a certain extent. If you have 100 BTC on address A, and spend small amounts (e.g. 0.4 BTC, 0.3 BTC etc) with the change (e.g. 99.6 BTC, 99.3 BTC, etc) going to address B and C, someone can sortof guess that A, B and C probably belong together.

However if you keep small amounts in your wallet, like 1 BTC, and you spend 0.4 BTC, meaning 0.4 BTC will go to X and 0.6 BTC will go to B, people can't tell for sure which was yours: X or B? (did you spend 0.4 or 0.6?) And so on - the more transactions you do, the less likely someone is to still link it together with any degree of certainty. Within a few cycles, the expanding transaction tree becomes unmanagable and nobody will be able to tell your addresses apart from others.

If you absolutely, positively need to be 100% certain nobody can link your addresses, use a mixer. This is very easy, but not free (mixing services charge a small fee). However, in practice, you shouldn't worry about this at all. Just put small amounts on your wallet, by the time it's almost empty, add a little extra from your savings, and so on. Really, nobody will know or care.

Let's say I have 100BTC in my main wallet and I want to pay people without them knowing about my main wallet.  How will an HD wallet help?  I could transfer small amounts from my main wallet to my HD wallet, but when I pay someone from my HD wallet, the inputs will come from an address funded by my main wallet every time.

With Mycelium, for example, you could create two wallets: one savings (your 'main wallet), and one spending. Both will be HD (all secured with the same, single backup) and nobody will be able to tell they're linked. Whenever you transfer some small amount from your savings wallet to your spending wallet, the remainder of your savings is moved to a new address.

Call me a retard but I would need like about 10 BTC to feel safe enough to spend BTC without feeling horrible in 3 years.

10 BTC is a lot of money. It is tough to say how much is enough.

You should not have a "main" bitcoin address. You should create a new address for every time you either send or receive bitcoin

If you use them you can always buy more. I guess I don't understand why people feel that the bitcoins in their wallet are more precious than all the others.

bitcoin is fungible. The above mindset is going to cause bitcoin to potentially fail as people give certain inputs more value then others.

It is illogical to not spend bitcoin on something you are going to buy anyway but can use bitcoin to get an overall lower price

How can retailers you're buying from see your bitcoin balance?

Have you seen many examples where bitcoin can get you a lower price?  If I buy something, I don't pay transaction fees. I just pay the purchase price. Are you seeing arbitrage opportunities between the USD (or fiat) and BTC price for the same item?

They can't. They can only see the balance of the particular address you're paying from. Since any decent wallet will not re-use any address and generate new ones after every single transaction, the information they have is pretty much zero.

With a little bit of work, anybody that knows an address in your wallet can determine a lower limit of the amount you have in the wallet at anytime. The more you reuse addresses, the closer that value is to the actual amount. Using a mixer will reduce the reliability of the value.

There is gyft, you would get a 3% discount here. I know that overstock has run a number of promotions offering discounts to people paying in bitcoin. There are also a number of other examples of discounts at local shops 

I used Mycelium for android btc wallet, user friendly, and have good features.

you can use bitmixer, check out my signature ;)

I think that sums it up really well odolvlobo.  Simply using an HD wallet affords little or no extra privacy.

https://play.google.com/store/apps/details?id=com.mycelium.wallet

mycelium is amazing, tx's are lightning fast, its interface is super lightweight, responsive etc..., it even works w/ HD wallets now and has a very good built in backup mechanism. Ive used it quite a bit. Never hurts to keep a few of ur spending btc in that wallet.
Even has a local trader functionality where u can look up people around u for buying / selling in person and u can easily become one urself =)

Using an HD wallet will typically keep you from ending up with 100BTC in a single address, but if you already have 100BTC in a single address because you were using a wallet with one address, then you'll have to use one of the suggestions above (mixer or exchange) to split your holdings.

I would start by transferring your 100BTC to an HD wallet that you will use as your "savings" wallet (i.e. don't keep this wallet on a mobile device, and make sure to properly back it up. Using a HD wallet will make sure that any time you send coins, the change will go to a newly address that isn't linked to anything else.

The transfer a smaller amount, let's say 2BTC, into the exchange of your choice. When you do that, the coins will become mixed with the rest of the users of that exchange. I would wait a day, or at least a few hours, before withdrawing to make sure it gets mixed well. Then withdraw a slightly different amount, say 1.8 BTC, to your Mycelium HD wallet to use as your "spending" wallet. Replenish this wallet to a balance that makes you comfortable.

I'll pass. Cant afford being a spender until i have at least 1 btc saved.

I'm sure to re-buy at Coinbase any amount I send from my main wallet to my spending mobile wallet.  Easy.

I see most people thinking like this. Can't blame them. It would be like spending gold on Kmart.

The problem is that the threshold keeps increasing.
When people have 1 BTC, they think I should save 2.  :)

Good for you! Need more people spending and using BTC as a currency.

There is nothing wrong with saving, and there is no reason why a person can't save and spend bitcoins at the same time.

Android wallet? The one from Schildbach would be nice. Been using it for more than a year now and so far there aren't any problems in regards to using that wallet. If you want to use your phone for storage and spending, try storing a small amount and keep it with care. Be sure to regularly make backups and store the file into an external hard drive or usb in case your phone fcked up or is lost.

As for the second question, a mixing service would be nice. It adds a layer of security to your coins and your main balance wouldn't be that easy to trace.

No, that's the good part: both Schildbach's wallet as well as Mycelium are HD wallets nowadays. That means you only have to make a backup once. It will be good forever, even for new addreses / private keys it generates in the future.

That's the same way I approach things with BTC.  If I do happen to spend any Bitcoin from Bitcoin Core wallet, I try to replenish it right away.

Buy, HODL, spend, BUY, HODL, spend...I think I got that routine perfected now.

Yep, with Coinbase, Circle, Buttercoin, it's really easy.

True.
Savers contribute a bit to increasing the price.
Spenders contribute a bit to increasing bitcoin adoption.
Nothing wrong with both,

i try to do what others do: spend my btc on things i want, and then buy back the spent btc as soon as i can. it works fairly well. :)