Added nil checks to reduce potential panics

hd_key.go

@@ -37,8 +37,8 @@ func GenerateHDKey(seedLength uint8) (hdKey *hdkeychain.ExtendedKey, err error)
 
 // GenerateHDKeyFromString will create a new master node for use in creating a
 // hierarchical deterministic key chain from an xPrivKey string
-func GenerateHDKeyFromString(xpriv string) (hdKey *hdkeychain.ExtendedKey, err error) {
-	return hdkeychain.NewKeyFromString(xpriv)
+func GenerateHDKeyFromString(xPriv string) (hdKey *hdkeychain.ExtendedKey, err error) {
+	return hdkeychain.NewKeyFromString(xPriv)
 }
 
 // GenerateHDKeyPair will generate a new xPub HD master node (xPrivateKey & xPublicKey)
@@ -111,12 +111,18 @@ func GetPrivateKeyByPath(hdKey *hdkeychain.ExtendedKey, chain, num uint32) (*bsv
 // GetPrivateKeyFromHDKey - helper function to get the Private Key associated
 // with a given hdKey
 func GetPrivateKeyFromHDKey(hdKey *hdkeychain.ExtendedKey) (*bsvec.PrivateKey, error) {
+	if hdKey == nil {
+		return nil, errors.New("hdKey is nil")
+	}
 	return hdKey.ECPrivKey()
 }
 
 // GetPublicKeyFromHDKey - helper function to get the Public Key associated
 // with a given hdKey
 func GetPublicKeyFromHDKey(hdKey *hdkeychain.ExtendedKey) (*bsvec.PublicKey, error) {
+	if hdKey == nil {
+		return nil, errors.New("hdKey is nil")
+	}
 	return hdKey.ECPubKey()
 }