[1F1tAaz5x1....]

Suppose I have an HD public xpubkey and I derive bitcoin public address(es) from it.
Given one of the public bitcoin address derived from it e.g. 1F1tAaz5x1....
Can you get the xpubkey e.g. xpub6DKUi1BvKEgn...
I thought it is impossible, but someone I know claims it is possible.
And if it is possible isn't the privacy compromised in this situation?

Not sure if this is directly related but also take a look at
Deterministic Wallets, Their Advantages and their Understated Flaws ("An Understated Problem" section):
https://bitcoinmagazine.com/articles/deterministic-wallets-advantages-flaw-1385450276/

[It was all fine yesterday]

Im on the latest version 0.16.0.2
Both testnet and main. Its just stuck on "Connecting to peers..."

It was all fine yesterday. And my testnet was completely synced.
But now no peers at all.
No changes in my firewall.
I tried to delete the "peers.dat". Bitcoin ABC recreated it. but no peers again.

Is there any known peer list I could add?
How to resolve this?
 

Thanks

[binaries]

I am desperately needing Bitcoin Core 0.15.1 with addrindex binaries for Windows.
Is it anywhere available for download?

I have found this:
https://github.com/btcdrak/bitcoin/releases

But it only supports 0.13 which is way too old  

And I found this
https://github.com/unsystemizer/bitcoin-core-addrindex

But there are no binaries, and I'm not a c++ programmer.
I need  to reliably query transactions by external address that are not in the Bitcoin Core wallet(s) - to get balances for addresses.

I can query my 0.15.1 full node, for TXs by adding txindex=1 but the addrindex feature is missing (I wonder why such important feature is missing?)

I really don't want to use an old 0.13 version and don't want to depend on external API.

Please advice and I will be forever grateful.

Suppose I have 3 unspent outputs:

tx: 3 BTC
tx: 2 BTC
tx: 1 BTC

Now I want to spend 2.5 BTC.
Which is preferred as input(s) and why?

A single:
3 BTC (Leaving my an output change of 0.5)?

Or:
1 BTC + 2BTC? (Leaving my an output change of 0.5)

I hope the question is clear.

I installed python27 on Windows, then the Twisted package via:
pip install Twisted

All went well. copied the txjsonrpc folder to the Armory root folder.

Running python armoryd.py gives me an error:

Code:

Traceback (most recent call last):
  File "armoryd.py", line 107, in <module>
    from armoryengine.ALL import *
ImportError: No module named armoryengine.ALL

What am I doing wrong?

Thanks!

Does blockchain.info keeps my private key(s) in their wallets of database? I am referring to the wallets on their website.
What other private information do they use?

The default keypool is set to 1000. What does it mean exactly? That I have a pool of 1000 keys/address to use?
If I reduce the -keekpool to say 20 the wallet size is drastically reduced from 1.5M  to 50k. and loads much faster?
Will I be able to add more keys later? or after I finish the 20 pool I must re-use addresses? Is there any danger in a keypol of 20?

Any will help be appreciated.

Does Armory supports RPC like Bitcoin Core?
Can I send RPC commands to it to query my wallet balance/transactions; create new wallet; etc... ?

In the bitcoin.conf we can add multiple entries of:

Code:

wallet=wallet.dat
wallet=wallet-2.dat
wallet=wallet-3.dat
wallet=wallet-4.dat
...

Is there currently a limit to how many wallets I can load at once?

Out of curiosity, How many full nodes belong to blockchain.info ?

I could not find this information. most of the links (in blockchain.info site) to that information are dead.

After I realized that Bitcoin Core does not supports multi-user/wallets I'm sadly trying to switch to other clients.  
Bitcoin core is great but is intended for a single user as I see it, even if multi-wallets will be dynamically supported in the unknown future .

From  this list:

https://en.bitcoin.it/wiki/Clients

Seems only suitable as full node multi-user are Armory and Gocoin.
Any recommendations?

I would really love RPC and Testnet support.

For that matter how does blockchain.info or Coppay/Bitpay connect to the blockchain? do they have their own full node(s) clients?
Or do they use a well known bitcoin client?

Thanks in advance.

Why is that considered a bad practice as opposed to ethereum addresses?
I read about it but still not convinced that the private key could be obtained from the public key (if that is the reason).
how would privacy could be compromised as opposed to ethereum blockchain?
Why not have a single address for both receiving and sending funds?

I'm very new to this so please excuse me.  

[reloadconfig]

I have seen the issue since 2011:

Signal and/or RPC call to re-read config file
https://github.com/bitcoin/bitcoin/issues/309

Reload bitcoin.conf without restarting the program
https://github.com/bitcoin/bitcoin/issues/1158

New option and configuration framework:
https://github.com/bitcoin/bitcoin/pull/394

New rpc command "reloadconfig" to dynamically update configuration parameters (Issue #309). Command line parameters will not be overridden. Notice that many core parameters are used only during startup.

But such command does not seem to exists.

Why do I need it? - it seems that adding an entry wallet=mynewwallet.dat will create a new mynewwallet.dat if it does not exists when the program starts.
This is good since I want to be able to dynamically add wallets in a multi-wallet mode. but the server needs to restart entirely which is bad for me.

Is there an option I missed in Bitcoin Core RPC to reload the conf file? My version is 0.15.1 on Windows 10.

Thanks.