Question about bitcoins addresses.

[juggolow22]

Ok I'm pretty sure I know what I'm doing most of the time. The only thing that im wondering is.

I have a instawallet app on my phone. It has a address.  I receive my bitcoins to that address. I give people that address to send me coins then I send it out to my block chain account. Got that down packed.

When I'm looking at my wallet on my phone I didn't set up a password. Their is no kind of encryption (that's know about). What stops a person from adding that Address to their instawallet and sending my funds else where. How is instawallet secure?  When I got that address it was only generated and thats it. Can't someone use that address too?

Another question is on block chain when I'm looking at my transaction list I see coins being deducted. What the reason for that. I'll receive .8 then lose .32 don't know what going on. If I'm posting in the wrong area please forgive me for not searching hard enough and "let othe flaming begin".

[Kazimir]

Just to be sure, exactly what do you mean with address?

If the address looks like this:
1GamFkuT3QHtHtEzKNVVnCrPvZYk2cqRQK
then it's just a regular bitcoin address. This is public, and safe to share with others. Anyone can send money there and see how much is on this address, but they can't spend the coins (they'd need the private key for that).

If it looks like an "instawallet address", like this:
https://instawallet.org/w/8XW1ANbiL32C6xzH6cJqOGLzvPekzCkIg
then it's an instawallet URL, which is NOT safe to share. This URLs refers not just to a bitcoin address, but to the corresponding private key as well. Anyone with this URL can spend your coins.

[MegaBrutal]

Actually, a full Bitcoin address consists of 2 keys:
- A public key, which is your public Bitcoin address which you can share with anyone. Anyone can send money to this address and view how much money is there on it, but anyone who wants to send the money from it, needs to know the private key.
- The private key, which is used to send Bitcoin transactions from the given address. Only those who possess the private key can send money from the given address. You may not share your private key with anyone. Private keys for your addresses are stored in your wallet file.

[juggolow22]

Ok so here's an example of what I'm talking about. I never got a private key for this. I just signed up on instawallet and they gave me this. I've been using it to receive coins. As you can see I haven't gotten enought to move it over to my block chain account witch I'm still confused about.
http://i693.photobucket.com/albums/vv292/juggolow22/269a6ec3.jpg


When I login into my block chain account, is the identifyer my private key?

Block chain account.
http://i693.photobucket.com/albums/vv292/juggolow22/e0fb6803.jpg

Blacked them out just incase

[MegaBrutal]

I can't tell it for sure for I've never actually seen any Bitcoin private keys; but the keys of your screenshots look like public Bitcoin addresses. But wait for someone else's affirmation.

[Stephen Gornick]

Instawallet is a different type of EWallet than Blockchain's wallet.

I just signed up on instawallet and they gave me this. I've been using it to receive coins.

That version looks different from mine.  Have you updated the app to the latest available on Google Play?

With the version I use, the "Unique ID" is not shown unless you gesture up on that QR code and it will then show.    

If you are going to have someone scan your QR code to send a transaction to you, tap the QR code and it will show a larger version and your Unique ID will not show.  Do not reveal your Unique ID to anyone.  It is all that is needed to access the funds -- it is like a bearer instrument/bearer code.

When I login into my block chain account, is the identifyer my private key?

That blockchain identifier is how you get access to be able to login to your Blockchain wallet.  That link with the Blockchain identifier is what you might add to your bookmarks so that you can access the wallet at a later time, but it doesn't necessarily need to be kept secret.  

You can edit your Blockchain account and associate an alias so that you don't even need to bookmark the URL with the identifier.  You should also edit the account and add your e-mail address so that you can have it send you an encrypted backup of the wallet.

The Blockchain wallet requires a password to access the wallet, so that is the only thing you need to keep private.