Bitcoin library vs script to develop application

I’m curious about the development of application of Identity management in Blockchain platform, but I’m a bit confused about the technologies to use.

In short words, when is more convenient to develop an application coding in script and when is it better to use a high-level library like BitcoinJ or a service as Blockchain.info API?

I’m a Java developer and I’m more confortable using a Java Library like bitcoinJ, but I don’t understand if, in this way, I can lose something in performance or expressivity or "semantic power" in regard to most raw-level scripting system of Bitcoin (that is a kind of assembler).

Thanks you in advance

bitcoin.rpc python library problem

I am working through Master Bitcoin. I got the bitcoin client up and running. I am now trying to access the client from python. In the example, there is a line that says from bitcoin.rpc import Rawproxy.

I get the error message no module named rpc. When I run pip freeze, I have python-bitcoinrpc==1.0 listed. Why can’t this module be found?

Store Bitcoins offline

I have some bitcoins and ether at Blockchain.info and I am really scared of losing them.

How do I best secure them? Right now I have a paper with the code to restore my wallet, but my coins are still stored at Blockchain.info.

Wouldn’t it be better to store them completely offline? How do I do this? What is the difference of storing them at Blockchain.info and keep a paper with the code to restore the wallet?

I guess if I store my coins at Blockchain.info, I have to trust that they don’t go bankrupt, they don’t steal my coins, and no one hacks their servers and steal my coins.

Therefore, I guess it’s more safe to store them physically, but I don’t understand how they are stored physically. From my understanding, I just create a code that can validate that I am the owner of the coins. So if I in the future want to see my coins, I can create an online wallet using the physically stored code?

What I basically want is to store my coins offline but have a wallet where I can see exactly how many coins I can access with the offline stored code (without giving the code to an online wallet).

I have also looked at Ledger, but they are very pricey and I don’t really see the value in them, since I still have to store a code on a physically printed paper to be sure I can still access the coins in case I break or lose the Ledger.

opening an old wallet.dat

I had about $8 USD worth of bitcoin in a wallet, and I backed up the wallet.dat to my dropbox. According to the modified date of the file this was in April 2013, so it was probaby from bitcoin qt version 0.8.1, or maybe a little earlier.

I basically left it there and haven’t done anything with bitcoin since then. Since it is worth probably at least $100 now I decided to check the exact amount.

I downloaded the latest version of bitcoin core, added the wallet.dat file to the data directory, started it with -rescan, and waited almost a month (!) for the blockchain data to get up to date. The balance showed as 0 the whole time. I thought it would update once the blockchain was totally downloaded, but it still just says 0.

Is this a problem with old vs new versions? Did I do something wrong? Next time, should I expect the balance to show a non-zero amount even if I haven’t downloaded the whole blockchain yet?

mSigna: Signed, send, but 0 confs despite high fee (0.001 BTC)

Tried to send my first tx from mSigna today. Receiving was painless, but the send does not get included into a block since half a day, and dozens of blocks passed.

I unlocked the account, created the tx, signed and sent it. The confirmation count for my receiving tx still rises (as more blocks arrive), but the one for the sending tx stays 0. Sounds like enough support to me…

I feel I am missing important information, like I need to do some step in addition?

The only calculation for the fees I found is at bitcoinfees, but it’s based on average tx size. It currently recommends 0.0002712 BTC, which is well below the fee I payed.

blockchain.info says “Transaction not found”. Looking at the adress at blockchain.info, it says “0 transactions”.

I’m running mSigna 0.10.6 with Bitcoin Core QT 0.14.2 (64bit) locally.

EDIT: As I read somewhere that transactions based on unconfirmed payments take longer than usual, I wanted to add that my receiving transaction is shown with over 6000 confirmations (again up from yesterday).

blockchain.info api (Balance Updates [POST]) confirmations not received

I’m trying to use “Balance Updates [POST] Monitor addresses for received and spent payments” from https://blockchain.info/api/api_receive

I subscribe to an address and get the response:

{
  "id": 15108,
  "addr": "1P9RQEr2XeE3PEb44ZE35sfZRRW1JHU8qx",
  "op": "ALL",
  "confs": 3,
  "callback": "https://d83bb66d.ngrok.io/bitcoin/confirmations",
  "onNotification": "DELETE"
}

then with each new transaction I get a notification with 0 confirmations, that looks like this:

{ 
   "address" : "1P9RQEr2XeE3PEb44ZE35sfZRRW1JHU8qx", 
   "confirmations" : 0, 
   "transaction_hash" : "38dbb8083a8c3006eae6c1194789941943cb60201ebfb03963188d4eb1d01d23", 
   "value" : -9030800 
 }

but I never get a notification with the 3rd confirmation

confs – Optional (Default 3). The number of confirmations the transaction needs to have before a notification is sent.

I tried setting confs to 1, 2 and leaving it as default, but I never get any confirmations, I have tried with different addresses, right now the transaction in this message has 5 confirmations but I didn’t get any notification.

https://btc.com/38dbb8083a8c3006eae6c1194789941943cb60201ebfb03963188d4eb1d01d23

does any one know what’s wrong ?

thanks