I'm using NBitcoin and I created an
ExtKey object. Now I need to get the Master Chain Code (see page 89 of Mastering Bitcoin for a good explanation) for this HD node. How do I do this?
According to Mastering Bitcoin a root seed is used with HMAC-SHA512 to create a 512-bits output. The left 256 bits are used for the master private key, the right 256 bits are used for the master chain code. When I call
GetBytes() on my
ExtKey object, however, it returns a byte array. This corresponds to 592 bits. I don't know what the extra 80 bits are so I can't just take the right 256 bits.