The code uses the vbytes to determine if the input key is private or public.

However, it's only checking against MAINNET_PRIVATE by default, which can lead to issues if you're using testnet prefixes.

`private = (vbytes == prefixes[0])`
has been changed to
`private = vbytes in PRIVATE`

With this change, both mainnet (xprv) and testnet (tprv) private keys will be recognized correctly.

Author: nicolas3355

cryptos/deterministic.py

@@ -74,7 +74,7 @@ def raw_bip32_ckd(rawtuple, i, prefixes=DEFAULT):
     vbytes, depth, fingerprint, oldi, chaincode, key = rawtuple
     i = int(i)
 
-    private = vbytes == prefixes[0]
+    private = (vbytes in PRIVATE)
 
     if private:
         priv = key