diff --git a/monero/seed.py b/monero/seed.py
index 21f31e9..07dd924 100644
--- a/monero/seed.py
+++ b/monero/seed.py
@@ -61,6 +61,9 @@ class Seed(object):
 
         self.word_list = wordlists.get_wordlist(wordlist)
 
+        self._ed_pub_spend_key = None
+        self._ed_pub_view_key = None
+
         if phrase_or_hex:
             seed_split = phrase_or_hex.split(" ")
             if len(seed_split) >= 24:
@@ -137,10 +140,16 @@ class Seed(object):
         return self.sc_reduce(h.digest())
 
     def public_spend_key(self):
-        return ed25519.public_from_secret_hex(self.secret_spend_key())
+        if self._ed_pub_spend_key:
+            return self._ed_pub_spend_key
+        self._ed_pub_spend_key = ed25519.public_from_secret_hex(self.secret_spend_key())
+        return self._ed_pub_spend_key
 
     def public_view_key(self):
-        return ed25519.public_from_secret_hex(self.secret_view_key())
+        if self._ed_pub_view_key:
+            return self._ed_pub_view_key
+        self._ed_pub_view_key = ed25519.public_from_secret_hex(self.secret_view_key())
+        return self._ed_pub_view_key
 
     def public_address(self, net='mainnet'):
         """Returns the master :class:`Address <monero.address.Address>` represented by the seed.