diff --git a/src/helper_bitcoin.py b/src/helper_bitcoin.py
index 9ac966d6..d56e395b 100644
--- a/src/helper_bitcoin.py
+++ b/src/helper_bitcoin.py
@@ -1,4 +1,5 @@
 import hashlib
+from pyelliptic import arithmetic
 
 # This function expects that pubkey begin with \x04
 def calculateBitcoinAddressFromPubkey(pubkey):