# You can verify or get more test data from: https://gist.github.com/zcc0721/ef0bf2e69f5e92b29d716981f2a8fe7d
# test data 1:
# xprv_str: 406c82307bf7978d17f3ecfeea7705370e9faef2027affa86c8027c6e11a8a50e231e65bd97048850ae6c39d0f46b63ae70aa24f5aac7877727c430c2201e6d6
-# root_xprv: 406c82307bf7978d17f3ecfeea7705370e9faef2027affa86c8027c6e11a8a50d828bf44b1a109c2bbb4c72685858e2f2ab8b405beef1e4ecc12d1ed8511e8eb
+# expanded_private_key_str_xprv: 406c82307bf7978d17f3ecfeea7705370e9faef2027affa86c8027c6e11a8a50d828bf44b1a109c2bbb4c72685858e2f2ab8b405beef1e4ecc12d1ed8511e8eb
# test data 2:
# xprv_str: 6032adeb967ac5ccbf988cf8190817bf9040c8cfd9cdfe3d5e400effb2946946d478b61cc6be936f367ae769eb1dc65c473ee73cac2eb43cf6d5e7c62b7f0062
-# root_xprv: 6032adeb967ac5ccbf988cf8190817bf9040c8cfd9cdfe3d5e400effb2946946ddbb71e7a76595c6bc24937d76085d24315713764cbdf1364ab9091953009cd8
+# expanded_private_key_str_xprv: 6032adeb967ac5ccbf988cf8190817bf9040c8cfd9cdfe3d5e400effb2946946ddbb71e7a76595c6bc24937d76085d24315713764cbdf1364ab9091953009cd8
# test data 3:
# xprv_str: 509a095ad862322641b8d66e84561aae1d4816045167e2c4dfadf464928e114300c0a162d41c0cdf196d61f4492f546e50bfff253b9d5d930d1bb89197cd333d
-# root_xprv: 509a095ad862322641b8d66e84561aae1d4816045167e2c4dfadf464928e11432787f5e10f9598f80fb41e4a648b609463c06e625641366f3279658b2b0f5268
+# expanded_private_key_str_xprv: 509a095ad862322641b8d66e84561aae1d4816045167e2c4dfadf464928e11432787f5e10f9598f80fb41e4a648b609463c06e625641366f3279658b2b0f5268
def xprv_to_expanded_private_key(xprv_str):
hc_str = hmac.HMAC(b'Expand', bytes.fromhex(xprv_str), digestmod=hashlib.sha512).hexdigest()
expanded_private_key_str = xprv_str[:64] + hc_str[64:]
# def xprv_sign(xprv_str, message_str):
+# expanded_private_key = xprv_to_expanded_private_key(xprv_str)
+
+# return signature_str
# xpub_verify verify signature