check seed in gui. fixes #622

lib/bitcoin.py

@@ -71,7 +71,25 @@ def mnemonic_to_seed(mnemonic, passphrase):
     return PBKDF2(mnemonic, 'mnemonic' + passphrase, iterations = PBKDF2_ROUNDS, macmodule = hmac, digestmodule = hashlib.sha512).read(64)
 
 from version import SEED_PREFIX
-is_seed = lambda x: hmac_sha_512("Seed version", x).encode('hex')[0:2].startswith(SEED_PREFIX)
+is_new_seed = lambda x: hmac_sha_512("Seed version", x).encode('hex')[0:2].startswith(SEED_PREFIX)
+
+def is_old_seed(seed):
+    import mnemonic
+    words = seed.strip().split()
+    try:
+        mnemonic.mn_decode(words)
+        uses_electrum_words = True
+    except Exception:
+        uses_electrum_words = False
+
+    try:
+        seed.decode('hex')
+        is_hex = True
+    except Exception:
+        is_hex = False
+         
+    return is_hex or (uses_electrum_words and len(words) == 12)
+
 
 # pywallet openssl private key implementation
 

lib/wallet.py

@@ -288,7 +288,7 @@ class NewWallet:
             # we keep only 13 words, that's approximately 139 bits of entropy
             words = mnemonic.mn_encode(s)[0:13] 
             seed = ' '.join(words)
-            if is_seed(seed):
+            if is_new_seed(seed):
                 break  # this will remove 8 bits of entropy
             nonce += 1
 
@@ -1781,36 +1781,23 @@ class Wallet(object):
 
 
     @classmethod
-    def from_seed(self, seed, storage):
-        import mnemonic
+    def is_seed(self, seed):
         if not seed:
-            return 
-
-        words = seed.strip().split()
-        try:
-            mnemonic.mn_decode(words)
-            uses_electrum_words = True
-        except Exception:
-            uses_electrum_words = False
-
-        try:
-            seed.decode('hex')
-            is_hex = True
-        except Exception:
-            is_hex = False
-         
-        if is_hex or (uses_electrum_words and len(words) == 12):
-            #print "old style wallet", len(words), words
-            w = OldWallet(storage)
-            w.init_seed(seed) #hex
-        else:
-            assert is_seed(seed)
-            w = NewWallet(storage)
-            w.init_seed(seed)
+            return False
+        elif is_old_seed(seed):
+            return OldWallet
+        elif is_new_seed(seed):
+            return NewWallet
+        else: 
+            return False
 
+    @classmethod
+    def from_seed(self, seed, storage):
+        klass = self.is_seed(seed)
+        w = klass(storage)
+        w.init_seed(seed)
         return w
 
-
     @classmethod
     def from_mpk(self, mpk, storage):