Add example on how to use a custom network

[dcousens]

Probably just need to outline something like the following:

var viacoin = {
  bip32: {
    public: 0x0488b21e,
    private: 0x0488ade4
  },
  dustThreshold: 560,
  feePerKb: 100000,
  magicPrefix: '\x18Viacoin Signed Message:\n',
  pubKeyHash: 0x47,
  scriptHash: 0x21,
  wif: 0xc7
}

The above is 1.5.x compatible, for 2.0.0 see here.

[ricmoo]

Another useful note would be what fields are required for which parts of the library? For example, to just encode/decode from WIF, only wif is necessary.

There do not seem to exist BIP32 prefixes for Namecoin (although I have generated some that generate a prefix of n, if interested... Is this the right thing to do? Or just use bitcoin's?), but they can be simply omitted if you are not using HDNode.

It would be nice to know when defining custom networks what is required for my feature set.

[jprichardson]

@ricmoo regarding BIP32 prefixes for different coins, I wouldn't recommend doing so as it's pretty redundant (assuming you follow BIP44). See https://github.com/bitcoin/bips/blob/master/bip-0043.mediawiki#node-serialization for more detail. i.e. using bitcoinjs-libwith a custom network in most cases will require you making sure that you have the WIF version correct. Take note though, that proof-of-stake coins do require different deserialization/serialization of transactions (due to the timestamp) - I'm working on a solution to address this, but it may be awhile.

[ricmoo]

Oh! That is PERFECT. I have been looking for that info documented somewhere. I noticed a few random alt-coins used their own prefixes.

Thanks. :)

[dcousens]

As of 2.0.0, the network type format would be aligned to this example:

  bitcoin: {
    messagePrefix: '\x18Bitcoin Signed Message:\n',
    bip32: {
      public: 0x0488b21e,
      private: 0x0488ade4
    },
    pubKeyHash: 0x00,
    scriptHash: 0x05,
    wif: 0x80,
    dustThreshold: 546
  },

[dcousens]

@jprichardson (and others) for what its worth, you should still specify the network object when calling HDNode.fromBase58, as it will default to bitcoin otherwise.