C#, NBitcoin and XPubkey

[galgitron]

I'm attempting to write an algorithm that generates public bitcoin addresses from a known xpubkey. The key I'm using for testing can be found at blockchain.info at

https://blockchain.info/xpub/xpub6CUGRUonZSQ4TWtTMmzXdrXDtypWKiKrhko4egpiMZbpiaQL2jkwSB1icqYh2cfDfVxdx4df189oLKnC5fSwqPfgyP3hooxujYzAu3fDVmz

I'm trying something like this to generate the address on the path 0,0,0, as below:

Code:

        var pubkey = new ExtPubKey(Encoding.ASCII.GetBytes("6CUGRUonZSQ4TWtTMmzXdrXDtypWKiKrhko4egpiMZbpiaQL2jkwSB1icqYh2cfDfVxdx4df189oLKnC5fSwqPfgyP3hooxujYzAu3fDVmz"));
        Console.Writeline(pubkey.Derive(0).Derive(0).Derive(0).PubKey.GetAddress(Network.Main));

I'm not fully understanding something because I get a 'Invalid point encoding 103' when trying to instantiate the ExtPubKey.  Does anyone have working sample code?

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[lontivero]

Well, there are a couple of things wrong in your code:

• ASCII encoding: most data in bitcoin is encoded with base58, no ascii.  
• xpub prefix: it is part of the xPub and you must not remove it.

Now, try this:

Code:

var pubkey = ExtPubKey.Parse("xpub6CUGRUonZSQ4TWtTMmzXdrXDtypWKiKrhko4egpiMZbpiaQL2jkwSB1icqYh2cfDfVxdx4df189oLKnC5fSwqPfgyP3hooxujYzAu3fDVmz");
var newAddress = pubkey.Derive(0).Derive(0).Derive(0).PubKey.GetAddress(Network.Main);
Console.WriteLine(newAddress);

BTW, I recommed you to try things in testnet first.

[galgitron]

That was it   Much appreciated my friend