diff --git a/doc/TODO b/doc/TODO
index b84785e596..9a257cf804 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -53,7 +53,7 @@ NICK      - Possible to get autoconf to easily install things into ~/.tor?
             key digest in place of nicknames.
           o Audit all uses of lookup-by-hostname and lookup-by-addr-port
             to search by digest when appropriate.
-NICK      - make sure to use addr/port in cpuworker tasks, because
+          o make sure to use addr/port in cpuworker tasks, because
             OPs don't have keys.
 NICK      - and fix the function comments in rephist
           o Rep-hist functions need to store info by keyid
diff --git a/src/or/cpuworker.c b/src/or/cpuworker.c
index 04b54fc00f..6b73d9510a 100644
--- a/src/or/cpuworker.c
+++ b/src/or/cpuworker.c
@@ -19,7 +19,7 @@ extern or_options_t options; /* command-line and config-file options */
 #define MIN_CPUWORKERS 1
 
 /** The tag specifies which circuit this onionskin was from. */
-#define TAG_LEN (DIGEST_LEN+2)
+#define TAG_LEN 8
 /** How many bytes are sent from tor to the cpuworker? */
 #define LEN_ONION_QUESTION (1+TAG_LEN+ONIONSKIN_CHALLENGE_LEN)
 /** How many bytes are sent from the cpuworker back to tor? */
@@ -55,17 +55,23 @@ int connection_cpu_finished_flushing(connection_t *conn) {
 
 /** Pack addr,port,and circ_id; set *tag to the result. (See note on
  * cpuworker_main for wire format.) */
-static void tag_pack(char *tag, uint16_t circ_id, const char *identity_digest){
-  *(uint16_t *)(tag) = circ_id;
-  memcpy(tag+2, identity_digest, DIGEST_LEN);
+static void tag_pack(char *tag, uint32_t addr, uint16_t port, uint16_t circ_id) {
+  *(uint32_t *)tag     = addr;
+  *(uint16_t *)(tag+4) = port;
+  *(uint16_t *)(tag+6) = circ_id;
 }
 
 /** Unpack <b>tag</b> into addr, port, and circ_id.
  */
-static void tag_unpack(const char *tag, uint16_t *circ_id,
-                       char *identity_digest) {
-  *circ_id = *(const uint16_t *)(tag);
-  memcpy(identity_digest, tag+2, DIGEST_LEN);
+static void tag_unpack(const char *tag, uint32_t *addr, uint16_t *port, uint16_t *circ_id) {
+  struct in_addr in;
+
+  *addr    = *(const uint32_t *)tag;
+  *port    = *(const uint16_t *)(tag+4);
+  *circ_id = *(const uint16_t *)(tag+6);
+
+  in.s_addr = htonl(*addr);
+  log_fn(LOG_DEBUG,"onion was from %s:%d, circ_id %d.", inet_ntoa(in), *port, *circ_id);
 }
 
 /** Called when the onion key has changed and we need to spawn new
@@ -92,10 +98,11 @@ void cpuworkers_rotate(void)
 int connection_cpu_process_inbuf(connection_t *conn) {
   char success;
   unsigned char buf[LEN_ONION_RESPONSE];
+  uint32_t addr;
+  uint16_t port;
   uint16_t circ_id;
   connection_t *p_conn;
   circuit_t *circ;
-  char identity_digest[DIGEST_LEN];
 
   tor_assert(conn && conn->type == CONN_TYPE_CPUWORKER);
 
@@ -123,11 +130,11 @@ int connection_cpu_process_inbuf(connection_t *conn) {
     connection_fetch_from_buf(buf,LEN_ONION_RESPONSE-1,conn);
 
     /* parse out the circ it was talking about */
-    tag_unpack(buf, &circ_id, identity_digest);
+    tag_unpack(buf, &addr, &port, &circ_id);
     circ = NULL;
     /* XXXX This is actually right: we want a specific port here in
      * case there are multiple connections. */
-    p_conn = connection_get_by_identity_digest(identity_digest,CONN_TYPE_OR);
+    p_conn = connection_exact_get_by_addr_port(addr,port);
     if(p_conn)
       circ = circuit_get_by_circ_id_conn(circ_id, p_conn);
 
@@ -177,6 +184,10 @@ done_processing:
  *          Opaque tag          TAG_LEN
  *          Onionskin challenge ONIONSKIN_REPLY_LEN
  *          Negotiated keys     KEY_LEN*2+DIGEST_LEN*2
+ *
+ *  (Note: this _should_ be by addr/port, since we're concerned with specific
+ * connections, not with routers (where we'd use identity).  Also, using
+ * identity would break pre-0.0.8 OPs, which don't have identity keys.)
  */
 static int cpuworker_main(void *data) {
   unsigned char question[ONIONSKIN_CHALLENGE_LEN];
@@ -351,7 +362,7 @@ int assign_to_cpuworker(connection_t *cpuworker, unsigned char question_type,
       log_fn(LOG_INFO,"circ->p_conn gone. Failing circ.");
       return -1;
     }
-    tag_pack(tag, circ->p_circ_id, circ->p_conn->identity_digest);
+    tag_pack(tag, circ->p_conn->addr, circ->p_conn->port, circ->p_circ_id);
 
     cpuworker->state = CPUWORKER_STATE_BUSY_ONION;
     num_cpuworkers_busy++;