diff --git a/lib/coins.py b/lib/coins.py
index 71129b6..334299e 100644
--- a/lib/coins.py
+++ b/lib/coins.py
@@ -215,9 +215,14 @@ class Coin(object):
         return Base58.encode_check(payload)
 
     @classmethod
-    def header_hashes(cls, header):
-        '''Given a header return the previous and current block hashes.'''
-        return header[4:36], double_sha256(header)
+    def header_hash(cls, header):
+        '''Given a header return hash'''
+        return double_sha256(header)
+
+    @classmethod
+    def header_prevhash(cls, header):
+        '''Given a header return previous hash'''
+        return header[4:36]
 
     @classmethod
     def read_block(cls, block):
@@ -368,10 +373,10 @@ class Dash(Coin):
     IRC_CHANNEL = "#electrum-dash"
 
     @classmethod
-    def header_hashes(cls, header):
-        '''Given a header return the previous and current block hashes.'''
+    def header_hash(cls, header):
+        '''Given a header return the hash.'''
         import x11_hash
-        return header[4:36], x11_hash.getPoWHash(header)
+        return x11_hash.getPoWHash(header)
 
 class DashTestnet(Dash):
     NAME = "Dash"
diff --git a/server/block_processor.py b/server/block_processor.py
index 144fb6a..583dad4 100644
--- a/server/block_processor.py
+++ b/server/block_processor.py
@@ -568,13 +568,12 @@ class BlockProcessor(server.db.DB):
         # the UTXO cache uses the FS cache via get_tx_hash() to
         # resolve compressed key collisions
         header, tx_hashes, txs = self.coin.read_block(block)
-        prev_hash, header_hash = self.coin.header_hashes(header)
-        if prev_hash != self.tip:
+        if self.tip != self.coin.header_prevhash(header):
             raise ChainReorg
 
         touched = set()
         self.fs_advance_block(header, tx_hashes, txs)
-        self.tip = header_hash
+        self.tip = self.coin.header_hash(header)
         self.height += 1
         undo_info = self.advance_txs(tx_hashes, txs, touched)
         if self.daemon.cached_height() - self.height <= self.reorg_limit:
@@ -636,14 +635,14 @@ class BlockProcessor(server.db.DB):
         touched = set()
         for block in blocks:
             header, tx_hashes, txs = self.coin.read_block(block)
-            prev_hash, header_hash = self.coin.header_hashes(header)
+            header_hash = self.coin.header_hash(header)
             if header_hash != self.tip:
                 raise ChainError('backup block {} is not tip {} at height {:,d}'
                                  .format(hash_to_str(header_hash),
                                          hash_to_str(self.tip), self.height))
 
             self.backup_txs(tx_hashes, txs, touched)
-            self.tip = prev_hash
+            self.tip = self.coin.header_prevhash(header)
             assert self.height >= 0
             self.height -= 1
             self.tx_counts.pop()
diff --git a/server/db.py b/server/db.py
index 58c7d9e..08a08e6 100644
--- a/server/db.py
+++ b/server/db.py
@@ -16,7 +16,7 @@ from bisect import bisect_right
 from collections import namedtuple
 
 from lib.util import chunks, formatted_time, LoggedClass
-from lib.hash import double_sha256, hash_to_str
+from lib.hash import hash_to_str
 from server.storage import open_db
 from server.version import VERSION
 
@@ -175,7 +175,7 @@ class DB(LoggedClass):
         headers = self.fs_read_headers(height, count)
         # FIXME: move to coins.py
         hlen = self.coin.HEADER_LEN
-        return [double_sha256(header) for header in chunks(headers, hlen)]
+        return [self.coin.header_hash(header) for header in chunks(headers, hlen)]
 
     @staticmethod
     def _resolve_limit(limit):