diff --git a/src/core/include.am b/src/core/include.am
index 9493f79552..8435ce0415 100644
--- a/src/core/include.am
+++ b/src/core/include.am
@@ -39,6 +39,7 @@ LIBTOR_APP_A_SOURCES = 				\
 	src/core/or/circuitpadding.c		\
 	src/core/or/circuitstats.c		\
 	src/core/or/circuituse.c		\
+	src/core/or/crypt_path.c		\
 	src/core/or/command.c			\
 	src/core/or/connection_edge.c		\
 	src/core/or/connection_or.c		\
@@ -247,6 +248,7 @@ noinst_HEADERS +=					\
 	src/core/or/connection_edge.h			\
 	src/core/or/connection_or.h			\
 	src/core/or/connection_st.h			\
+	src/core/or/crypt_path.h      		\
 	src/core/or/cpath_build_state_st.h		\
 	src/core/or/crypt_path_reference_st.h		\
 	src/core/or/crypt_path_st.h			\
diff --git a/src/core/mainloop/connection.c b/src/core/mainloop/connection.c
index 30504e4edb..f6adfa765a 100644
--- a/src/core/mainloop/connection.c
+++ b/src/core/mainloop/connection.c
@@ -82,6 +82,7 @@
 #include "core/or/policies.h"
 #include "core/or/reasons.h"
 #include "core/or/relay.h"
+#include "core/or/crypt_path.h"
 #include "core/proto/proto_http.h"
 #include "core/proto/proto_socks.h"
 #include "feature/client/dnsserv.h"
diff --git a/src/core/or/circuitlist.c b/src/core/or/circuitlist.c
index 6428cdb8a7..ee9e89f380 100644
--- a/src/core/or/circuitlist.c
+++ b/src/core/or/circuitlist.c
@@ -63,6 +63,7 @@
 #include "core/or/circuituse.h"
 #include "core/or/circuitstats.h"
 #include "core/or/circuitpadding.h"
+#include "core/or/crypt_path.h"
 #include "core/mainloop/connection.h"
 #include "app/config/config.h"
 #include "core/or/connection_edge.h"
@@ -2785,59 +2786,6 @@ circuits_handle_oom(size_t current_allocation)
              n_dirconns_killed);
 }
 
-/** Verify that cpath layer <b>cp</b> has all of its invariants
- * correct. Trigger an assert if anything is invalid.
- */
-void
-assert_cpath_layer_ok(const crypt_path_t *cp)
-{
-//  tor_assert(cp->addr); /* these are zero for rendezvous extra-hops */
-//  tor_assert(cp->port);
-  tor_assert(cp);
-  tor_assert(cp->magic == CRYPT_PATH_MAGIC);
-  switch (cp->state)
-    {
-    case CPATH_STATE_OPEN:
-      relay_crypto_assert_ok(&cp->crypto);
-      /* fall through */
-    case CPATH_STATE_CLOSED:
-      /*XXXX Assert that there's no handshake_state either. */
-      tor_assert(!cp->rend_dh_handshake_state);
-      break;
-    case CPATH_STATE_AWAITING_KEYS:
-      /* tor_assert(cp->dh_handshake_state); */
-      break;
-    default:
-      log_fn(LOG_ERR, LD_BUG, "Unexpected state %d", cp->state);
-      tor_assert(0);
-    }
-  tor_assert(cp->package_window >= 0);
-  tor_assert(cp->deliver_window >= 0);
-}
-
-/** Verify that cpath <b>cp</b> has all of its invariants
- * correct. Trigger an assert if anything is invalid.
- */
-static void
-assert_cpath_ok(const crypt_path_t *cp)
-{
-  const crypt_path_t *start = cp;
-
-  do {
-    assert_cpath_layer_ok(cp);
-    /* layers must be in sequence of: "open* awaiting? closed*" */
-    if (cp != start) {
-      if (cp->state == CPATH_STATE_AWAITING_KEYS) {
-        tor_assert(cp->prev->state == CPATH_STATE_OPEN);
-      } else if (cp->state == CPATH_STATE_OPEN) {
-        tor_assert(cp->prev->state == CPATH_STATE_OPEN);
-      }
-    }
-    cp = cp->next;
-    tor_assert(cp);
-  } while (cp != start);
-}
-
 /** Verify that circuit <b>c</b> has all of its invariants
  * correct. Trigger an assert if anything is invalid.
  */
diff --git a/src/core/or/circuitlist.h b/src/core/or/circuitlist.h
index f34f4ed6b7..a50e23716a 100644
--- a/src/core/or/circuitlist.h
+++ b/src/core/or/circuitlist.h
@@ -228,7 +228,6 @@ int circuit_count_pending_on_channel(channel_t *chan);
 #define circuit_mark_for_close(c, reason)                               \
   circuit_mark_for_close_((c), (reason), __LINE__, SHORT_FILE__)
 
-void assert_cpath_layer_ok(const crypt_path_t *cp);
 MOCK_DECL(void, assert_circuit_ok,(const circuit_t *c));
 void circuit_free_all(void);
 void circuits_handle_oom(size_t current_allocation);
diff --git a/src/core/or/crypt_path.c b/src/core/or/crypt_path.c
new file mode 100644
index 0000000000..d4fc59630a
--- /dev/null
+++ b/src/core/or/crypt_path.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file crypt_path.c
+ *
+ * \brief Functions dealing with layered circuit encryption. This file aims to
+ *   provide an API around the crypt_path_t structure which holds crypto
+ *   information about a specific hop of a circuit.
+ **/
+
+#define CRYPT_PATH_PRIVATE
+
+#include "core/or/or.h"
+#include "core/or/crypt_path.h"
+
+#include "core/crypto/relay_crypto.h"
+
+#include "core/or/crypt_path_st.h"
+
+/** Verify that cpath <b>cp</b> has all of its invariants
+ * correct. Trigger an assert if anything is invalid.
+ */
+void
+assert_cpath_ok(const crypt_path_t *cp)
+{
+  const crypt_path_t *start = cp;
+
+  do {
+    assert_cpath_layer_ok(cp);
+    /* layers must be in sequence of: "open* awaiting? closed*" */
+    if (cp != start) {
+      if (cp->state == CPATH_STATE_AWAITING_KEYS) {
+        tor_assert(cp->prev->state == CPATH_STATE_OPEN);
+      } else if (cp->state == CPATH_STATE_OPEN) {
+        tor_assert(cp->prev->state == CPATH_STATE_OPEN);
+      }
+    }
+    cp = cp->next;
+    tor_assert(cp);
+  } while (cp != start);
+}
+
+/** Verify that cpath layer <b>cp</b> has all of its invariants
+ * correct. Trigger an assert if anything is invalid.
+ */
+void
+assert_cpath_layer_ok(const crypt_path_t *cp)
+{
+//  tor_assert(cp->addr); /* these are zero for rendezvous extra-hops */
+//  tor_assert(cp->port);
+  tor_assert(cp);
+  tor_assert(cp->magic == CRYPT_PATH_MAGIC);
+  switch (cp->state)
+    {
+    case CPATH_STATE_OPEN:
+      relay_crypto_assert_ok(&cp->crypto);
+      /* fall through */
+    case CPATH_STATE_CLOSED:
+      /*XXXX Assert that there's no handshake_state either. */
+      tor_assert(!cp->rend_dh_handshake_state);
+      break;
+    case CPATH_STATE_AWAITING_KEYS:
+      /* tor_assert(cp->dh_handshake_state); */
+      break;
+    default:
+      log_fn(LOG_ERR, LD_BUG, "Unexpected state %d", cp->state);
+      tor_assert(0);
+    }
+  tor_assert(cp->package_window >= 0);
+  tor_assert(cp->deliver_window >= 0);
+}
+
diff --git a/src/core/or/crypt_path.h b/src/core/or/crypt_path.h
new file mode 100644
index 0000000000..a9b9aae43d
--- /dev/null
+++ b/src/core/or/crypt_path.h
@@ -0,0 +1,11 @@
+/**
+ * \file crypt_path.h
+ * \brief Header file for crypt_path.c.
+ **/
+
+/* rename */
+void assert_cpath_layer_ok(const crypt_path_t *cp);
+
+/* rename */
+void assert_cpath_ok(const crypt_path_t *cp);
+