diff --git a/src/common/address.c b/src/common/address.c
index 1bd52d24b6..68ad639411 100644
--- a/src/common/address.c
+++ b/src/common/address.c
@@ -1181,6 +1181,9 @@ tor_addr_compare_masked(const tor_addr_t *addr1, const tor_addr_t *addr2,
   }
 }
 
+/** Input for siphash, to produce some output for an unspec value. */
+static const uint32_t unspec_hash_input[] = { 0x4e4df09f, 0x92985342 };
+
 /** Return a hash code based on the address addr. DOCDOC extra */
 uint64_t
 tor_addr_hash(const tor_addr_t *addr)
@@ -1189,7 +1192,7 @@ tor_addr_hash(const tor_addr_t *addr)
   case AF_INET:
     return siphash24g(&addr->addr.in_addr.s_addr, 4);
   case AF_UNSPEC:
-    return 0x4e4d5342;
+    return siphash24g(unspec_hash_input, sizeof(unspec_hash_input));
   case AF_INET6:
     return siphash24g(&addr->addr.in6_addr.s6_addr, 16);
   default:
@@ -1211,7 +1214,7 @@ tor_addr_keyed_hash(const struct sipkey *key, const tor_addr_t *addr)
   case AF_INET:
     return siphash24(&addr->addr.in_addr.s_addr, 4, key);
   case AF_UNSPEC:
-    return 0x4e4d5342;
+    return siphash24(unspec_hash_input, sizeof(unspec_hash_input), key);
   case AF_INET6:
     return siphash24(&addr->addr.in6_addr.s6_addr, 16, key);
   default: