From 61ec18f9c8a4552c209416ce363592e35e416997 Mon Sep 17 00:00:00 2001
From: Chris Pacia <ctpacia@gmail.com>
Date: Mon, 5 Jun 2017 14:41:43 -0400
Subject: [PATCH] Export NewExtendedKey

Allow users to create custom ExtendedKeys by exporting the newExtendedKey function.
The comment is updated to reflect that this function is only intended to be used
by custom applications.
---
 hdkeychain/extendedkey.go | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/hdkeychain/extendedkey.go b/hdkeychain/extendedkey.go
index e8ebec2..b634cd0 100644
--- a/hdkeychain/extendedkey.go
+++ b/hdkeychain/extendedkey.go
@@ -116,10 +116,12 @@ type ExtendedKey struct {
 	isPrivate bool
 }
 
-// newExtendedKey returns a new instance of an extended key with the given
+// NewExtendedKey returns a new instance of an extended key with the given
 // fields.  No error checking is performed here as it's only intended to be a
-// convenience method used to create a populated struct.
-func newExtendedKey(version, key, chainCode, parentFP []byte, depth uint8,
+// convenience method used to create a populated struct. This function should
+// only by used by applications that need to create custom ExtendedKeys. All
+// other applications should just use NewMaster, Child, or Neuter.
+func NewExtendedKey(version, key, chainCode, parentFP []byte, depth uint8,
 	childNum uint32, isPrivate bool) *ExtendedKey {
 
 	// NOTE: The pubKey field is intentionally left nil so it is only
@@ -315,7 +317,7 @@ func (k *ExtendedKey) Child(i uint32) (*ExtendedKey, error) {
 	// The fingerprint of the parent for the derived child is the first 4
 	// bytes of the RIPEMD160(SHA256(parentPubKey)).
 	parentFP := btcutil.Hash160(k.pubKeyBytes())[:4]
-	return newExtendedKey(k.version, childKey, childChainCode, parentFP,
+	return NewExtendedKey(k.version, childKey, childChainCode, parentFP,
 		k.depth+1, i, isPrivate), nil
 }
 
@@ -343,7 +345,7 @@ func (k *ExtendedKey) Neuter() (*ExtendedKey, error) {
 	// key will simply be the pubkey of the current extended private key.
 	//
 	// This is the function N((k,c)) -> (K, c) from [BIP32].
-	return newExtendedKey(version, k.pubKeyBytes(), k.chainCode, k.parentFP,
+	return NewExtendedKey(version, k.pubKeyBytes(), k.chainCode, k.parentFP,
 		k.depth, k.childNum, false), nil
 }
 
@@ -487,7 +489,7 @@ func NewMaster(seed []byte, net *chaincfg.Params) (*ExtendedKey, error) {
 	}
 
 	parentFP := []byte{0x00, 0x00, 0x00, 0x00}
-	return newExtendedKey(net.HDPrivateKeyID[:], secretKey, chainCode,
+	return NewExtendedKey(net.HDPrivateKeyID[:], secretKey, chainCode,
 		parentFP, 0, 0, true), nil
 }
 
@@ -541,7 +543,7 @@ func NewKeyFromString(key string) (*ExtendedKey, error) {
 		}
 	}
 
-	return newExtendedKey(version, keyData, chainCode, parentFP, depth,
+	return NewExtendedKey(version, keyData, chainCode, parentFP, depth,
 		childNum, isPrivate), nil
 }