diff --git a/src/core/crypto/relay_crypto.c b/src/core/crypto/relay_crypto.c
index d4116d47ab..94e9060651 100644
--- a/src/core/crypto/relay_crypto.c
+++ b/src/core/crypto/relay_crypto.c
@@ -143,12 +143,9 @@ relay_decrypt_cell(circuit_t *circ, cell_t *cell,
             *recognized = 1;
             *layer_hint = thishop;
             /* Keep current digest of this cell for the possible SENDME. */
-            if (thishop->crypto.sendme_digest) {
-              crypto_digest_free(thishop->crypto.sendme_digest);
-            }
-            thishop->crypto.sendme_digest =
-              crypto_digest_dup(thishop->crypto.b_digest);
-
+            crypto_digest_get_digest(thishop->crypto.b_digest,
+                                     (char *) thishop->crypto.sendme_digest,
+                                     sizeof(thishop->crypto.sendme_digest));
             return 0;
           }
         }
@@ -220,10 +217,9 @@ relay_encrypt_cell_inbound(cell_t *cell,
 {
   relay_set_digest(or_circ->crypto.b_digest, cell);
   /* Keep a record of this cell, we might use it for validating the SENDME. */
-  if (or_circ->crypto.sendme_digest) {
-    crypto_digest_free(or_circ->crypto.sendme_digest);
-  }
-  or_circ->crypto.sendme_digest = crypto_digest_dup(or_circ->crypto.b_digest);
+  crypto_digest_get_digest(or_circ->crypto.b_digest,
+                           (char *) or_circ->crypto.sendme_digest,
+                           sizeof(or_circ->crypto.sendme_digest));
   /* encrypt one layer */
   relay_crypt_one_payload(or_circ->crypto.b_crypto, cell->payload);
 }
@@ -241,7 +237,6 @@ relay_crypto_clear(relay_crypto_t *crypto)
   crypto_cipher_free(crypto->b_crypto);
   crypto_digest_free(crypto->f_digest);
   crypto_digest_free(crypto->b_digest);
-  crypto_digest_free(crypto->sendme_digest);
 }
 
 /** Initialize <b>crypto</b> from the key material in key_data.
diff --git a/src/core/or/relay_crypto_st.h b/src/core/or/relay_crypto_st.h
index dbdf1599dc..1f243ccdc8 100644
--- a/src/core/or/relay_crypto_st.h
+++ b/src/core/or/relay_crypto_st.h
@@ -26,7 +26,7 @@ struct relay_crypto_t {
   struct crypto_digest_t *b_digest;
 
   /** Digest used for the next SENDME cell if any. */
-  struct crypto_digest_t *sendme_digest;
+  uint8_t sendme_digest[DIGEST_LEN];
 };
 #undef crypto_cipher_t
 
diff --git a/src/core/or/sendme.c b/src/core/or/sendme.c
index 0a7b1cbc02..3dcd9df08e 100644
--- a/src/core/or/sendme.c
+++ b/src/core/or/sendme.c
@@ -215,7 +215,7 @@ sendme_is_valid(const circuit_t *circ, const uint8_t *cell_payload,
  * Return the size in bytes of the encoded cell in payload. A negative value
  * is returned on encoding failure. */
 STATIC ssize_t
-build_cell_payload_v1(crypto_digest_t *cell_digest, uint8_t *payload)
+build_cell_payload_v1(const uint8_t *cell_digest, uint8_t *payload)
 {
   ssize_t len = -1;
   sendme_cell_t *cell = NULL;
@@ -231,9 +231,8 @@ build_cell_payload_v1(crypto_digest_t *cell_digest, uint8_t *payload)
   sendme_cell_set_data_len(cell, TRUNNEL_SENDME_V1_DIGEST_LEN);
 
   /* Copy the digest into the data payload. */
-  crypto_digest_get_digest(cell_digest,
-                           (char *) sendme_cell_getarray_data_v1_digest(cell),
-                           sendme_cell_get_data_len(cell));
+  memcpy(sendme_cell_getarray_data_v1_digest(cell), cell_digest,
+         sendme_cell_get_data_len(cell));
 
   /* Finally, encode the cell into the payload. */
   len = sendme_cell_encode(payload, RELAY_PAYLOAD_SIZE, cell);
@@ -249,7 +248,7 @@ build_cell_payload_v1(crypto_digest_t *cell_digest, uint8_t *payload)
  * because we failed to send the cell on it. */
 static int
 send_circuit_level_sendme(circuit_t *circ, crypt_path_t *layer_hint,
-                          crypto_digest_t *cell_digest)
+                          const uint8_t *cell_digest)
 {
   uint8_t emit_version;
   uint8_t payload[RELAY_PAYLOAD_SIZE];
@@ -340,7 +339,7 @@ sendme_connection_edge_consider_sending(edge_connection_t *conn)
 void
 sendme_circuit_consider_sending(circuit_t *circ, crypt_path_t *layer_hint)
 {
-  crypto_digest_t *digest;
+  const uint8_t *digest;
 
   while ((layer_hint ? layer_hint->deliver_window : circ->deliver_window) <=
           CIRCWINDOW_START - CIRCWINDOW_INCREMENT) {
@@ -539,7 +538,7 @@ sendme_note_stream_data_packaged(edge_connection_t *conn)
 void
 sendme_note_cell_digest(circuit_t *circ)
 {
-  uint8_t *digest;
+  const uint8_t *digest;
 
   tor_assert(circ);
 
@@ -555,16 +554,10 @@ sendme_note_cell_digest(circuit_t *circ)
     return;
   }
 
-  /* Only note the digest if we actually have the digest of the previous cell
-   * recorded. It should never happen in theory as we always record the last
-   * digest for the v1 SENDME. */
-  if (TO_OR_CIRCUIT(circ)->crypto.sendme_digest) {
-    digest = tor_malloc_zero(TRUNNEL_SENDME_V1_DIGEST_LEN);
-    crypto_digest_get_digest(TO_OR_CIRCUIT(circ)->crypto.sendme_digest,
-                             (char *) digest, TRUNNEL_SENDME_V1_DIGEST_LEN);
-    if (circ->sendme_last_digests == NULL) {
-      circ->sendme_last_digests = smartlist_new();
-    }
-    smartlist_add(circ->sendme_last_digests, digest);
+  /* Add the digest to the last seen list in the circuit. */
+  digest = TO_OR_CIRCUIT(circ)->crypto.sendme_digest;
+  if (circ->sendme_last_digests == NULL) {
+    circ->sendme_last_digests = smartlist_new();
   }
+  smartlist_add(circ->sendme_last_digests, tor_memdup(digest, DIGEST_LEN));
 }
diff --git a/src/core/or/sendme.h b/src/core/or/sendme.h
index 2154a29f4a..71df9b6f07 100644
--- a/src/core/or/sendme.h
+++ b/src/core/or/sendme.h
@@ -50,7 +50,7 @@ STATIC int get_accept_min_version(void);
 
 STATIC bool cell_version_is_valid(uint8_t cell_version);
 
-STATIC ssize_t build_cell_payload_v1(crypto_digest_t *cell_digest,
+STATIC ssize_t build_cell_payload_v1(const uint8_t *cell_digest,
                                      uint8_t *payload);
 STATIC bool sendme_is_valid(const circuit_t *circ,
                             const uint8_t *cell_payload,
diff --git a/src/test/test_relaycell.c b/src/test/test_relaycell.c
index c4ed215c7c..0623583511 100644
--- a/src/test/test_relaycell.c
+++ b/src/test/test_relaycell.c
@@ -705,7 +705,6 @@ test_circbw_relay(void *arg)
   circ = helper_create_origin_circuit(CIRCUIT_PURPOSE_C_GENERAL, 0);
   circ->cpath->state = CPATH_STATE_AWAITING_KEYS;
   circ->cpath->deliver_window = CIRCWINDOW_START;
-  circ->cpath->crypto.sendme_digest = crypto_digest_new();
 
   entryconn1 = fake_entry_conn(circ, 1);
   edgeconn = ENTRY_TO_EDGE_CONN(entryconn1);
diff --git a/src/test/test_sendme.c b/src/test/test_sendme.c
index 92f478df0e..d6410a7488 100644
--- a/src/test/test_sendme.c
+++ b/src/test/test_sendme.c
@@ -16,6 +16,8 @@
 #include "feature/nodelist/networkstatus.h"
 #include "feature/nodelist/networkstatus_st.h"
 
+#include "lib/crypt_ops/crypto_digest.h"
+
 #include "test/test.h"
 #include "test/log_test_helpers.h"
 
@@ -64,7 +66,6 @@ test_v1_note_digest(void *arg)
   circuit_free_(circ);
   /* Points it to the OR circuit now. */
   circ = TO_CIRCUIT(or_circ);
-  or_circ->crypto.sendme_digest = crypto_digest_new();
 
   /* The package window has to be a multiple of CIRCWINDOW_INCREMENT minus 1
    * in order to catched the CIRCWINDOW_INCREMENT-nth cell. Try something that
@@ -144,7 +145,7 @@ test_v1_consensus_params(void *arg)
 static void
 test_v1_build_cell(void *arg)
 {
-  uint8_t payload[RELAY_PAYLOAD_SIZE];
+  uint8_t payload[RELAY_PAYLOAD_SIZE], digest[DIGEST_LEN];
   ssize_t ret;
   crypto_digest_t *cell_digest = NULL;
   or_circuit_t *or_circ = NULL;
@@ -156,11 +157,12 @@ test_v1_build_cell(void *arg)
   circ = TO_CIRCUIT(or_circ);
 
   cell_digest = crypto_digest_new();
-  crypto_digest_add_bytes(cell_digest, "AAAAAAAAAAAAAAAAAAAA", 20);
   tt_assert(cell_digest);
+  crypto_digest_add_bytes(cell_digest, "AAAAAAAAAAAAAAAAAAAA", 20);
+  crypto_digest_get_digest(cell_digest, (char *) digest, sizeof(digest));
 
   /* SENDME v1 payload is 3 bytes + 20 bytes digest. See spec. */
-  ret = build_cell_payload_v1(cell_digest, payload);
+  ret = build_cell_payload_v1(digest, payload);
   tt_int_op(ret, OP_EQ, 23);
 
   /* Validation. */
@@ -183,7 +185,6 @@ test_v1_build_cell(void *arg)
   teardown_capture_of_logs();
 
   /* Note the wrong digest in the circuit, cell should fail validation. */
-  or_circ->crypto.sendme_digest = crypto_digest_new();
   circ->package_window = CIRCWINDOW_INCREMENT + 1;
   sendme_note_cell_digest(circ);
   tt_int_op(smartlist_len(circ->sendme_last_digests), OP_EQ, 1);
@@ -194,11 +195,8 @@ test_v1_build_cell(void *arg)
   expect_log_msg_containing("SENDME v1 cell digest do not match.");
   teardown_capture_of_logs();
 
-  /* Cleanup */
-  crypto_digest_free(or_circ->crypto.sendme_digest);
-
   /* Record the cell digest into the circuit, cell should validate. */
-  or_circ->crypto.sendme_digest = crypto_digest_dup(cell_digest);
+  memcpy(or_circ->crypto.sendme_digest, digest, sizeof(digest));
   circ->package_window = CIRCWINDOW_INCREMENT + 1;
   sendme_note_cell_digest(circ);
   tt_int_op(smartlist_len(circ->sendme_last_digests), OP_EQ, 1);