diff --git a/monero/seed.py b/monero/seed.py
index 3accabc..4f3c1de 100644
--- a/monero/seed.py
+++ b/monero/seed.py
@@ -85,6 +85,9 @@ class Seed(object):
             self.hex = generate_hex()
             self.encode_seed()
 
+    def is_mymonero(self):
+        """Returns True if the seed is MyMonero-style (12/13-word)."""
+        return len(self.hex) == 32
 
     def endian_swap(self, word):
         """Given any string, swap bits and return the result.
@@ -152,12 +155,19 @@ class Seed(object):
     def hex_seed(self):
         return self.hex
 
+    def _hex_seed_keccak(self):
+        h = keccak_256()
+        h.update(unhexlify(self.hex))
+        return h.hexdigest()
+
     def secret_spend_key(self):
-        return self.sc_reduce(self.hex)
+        a = self._hex_seed_keccak() if self.is_mymonero() else self.hex
+        return self.sc_reduce(a)
 
     def secret_view_key(self):
+        b = self._hex_seed_keccak() if self.is_mymonero() else self.secret_spend_key()
         h = keccak_256()
-        h.update(unhexlify(self.secret_spend_key()))
+        h.update(unhexlify(b))
         return self.sc_reduce(h.hexdigest())
 
     def public_spend_key(self):
diff --git a/tests/test_seed.py b/tests/test_seed.py
index e000ba3..1d12993 100644
--- a/tests/test_seed.py
+++ b/tests/test_seed.py
@@ -66,6 +66,7 @@ class SeedTestCase(unittest.TestCase):
         seed = Seed("adjust mugged vaults atlas nasty mews damp toenail suddenly toxic possible "\
             "framed succeed fuzzy return demonstrate nucleus album noises peculiar virtual "\
             "rowboat inorganic jester fuzzy")
+        self.assertFalse(seed.is_mymonero())
         self.assertTrue(seed.validate_checksum())
         self.assertEqual(
             seed.secret_spend_key(),
@@ -87,6 +88,7 @@ class SeedTestCase(unittest.TestCase):
             '54pZ5jHDGmwNnycvZbUoj44vsbAEmKnx9aNgkjHdjtMsBrSeKiY8J4s2raH7EMawA2Fwo9utaRTV7Aw8EcTMNMxhH6cuARW')
 
         seed = Seed("dwelt idols lopped blender haggled rabbits piloted value swagger taunts toolbox upgrade swagger")
+        self.assertTrue(seed.is_mymonero())
         self.assertTrue(seed.validate_checksum())
         # the following fails, #21 addresses that
         self.assertEqual(