diff --git a/src/allmydata/dirnode.py b/src/allmydata/dirnode.py
index d181cd7f9..83a96ece0 100644
--- a/src/allmydata/dirnode.py
+++ b/src/allmydata/dirnode.py
@@ -195,7 +195,7 @@ class NewDirectoryNode:
 
     def _encrypt_rwcap(self, rwcap):
         assert isinstance(rwcap, str)
-        salt = hashutil.mutable_rwcap_iv_hash(rwcap)
+        salt = hashutil.mutable_rwcap_salt_hash(rwcap)
         key = hashutil.mutable_rwcap_key_hash(salt, self._node.get_writekey())
         cryptor = AES(key)
         crypttext = cryptor.process(rwcap)
diff --git a/src/allmydata/util/hashutil.py b/src/allmydata/util/hashutil.py
index 8987d2dc4..883f27c6e 100644
--- a/src/allmydata/util/hashutil.py
+++ b/src/allmydata/util/hashutil.py
@@ -82,7 +82,7 @@ MUTABLE_STORAGEINDEX_TAG = "allmydata_mutable_readkey_to_storage_index_v1"
 
 # dirnodes
 DIRNODE_CHILD_WRITECAP_TAG = "allmydata_mutable_writekey_and_salt_to_dirnode_child_capkey_v1"
-DIRNODE_CHILD_IV_TAG = "allmydata_mutable_writekey_to_iv_v1"
+DIRNODE_CHILD_SALT_TAG = "allmydata_dirnode_child_rwcap_to_salt_v1"
 
 def storage_index_hash(key):
     # storage index is truncated to 128 bits (16 bytes). We're only hashing a
@@ -172,8 +172,8 @@ def hmac(tag, data):
 
 def mutable_rwcap_key_hash(iv, writekey):
     return tagged_pair_hash(DIRNODE_CHILD_WRITECAP_TAG, iv, writekey, KEYLEN)
-def mutable_rwcap_iv_hash(writekey):
-    return tagged_hash(DIRNODE_CHILD_IV_TAG, writekey, IVLEN)
+def mutable_rwcap_salt_hash(writekey):
+    return tagged_hash(DIRNODE_CHILD_SALT_TAG, writekey, IVLEN)
 
 def ssk_writekey_hash(privkey):
     return tagged_hash(MUTABLE_WRITEKEY_TAG, privkey, KEYLEN)