diff --git a/bootutil/src/bootutil_priv.h b/bootutil/src/bootutil_priv.h
new file mode 100644
index 0000000..79885ae
--- /dev/null
+++ b/bootutil/src/bootutil_priv.h
@@ -0,0 +1,109 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef H_BOOTUTIL_PRIV_
+#define H_BOOTUTIL_PRIV_
+
+#include "syscfg/syscfg.h"
+#include "bootutil/image.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct flash_area;
+
+#define BOOT_EFLASH     1
+#define BOOT_EFILE      2
+#define BOOT_EBADIMAGE  3
+#define BOOT_EBADVECT   4
+#define BOOT_EBADSTATUS 5
+#define BOOT_ENOMEM     6
+#define BOOT_EBADARGS   7
+
+#define BOOT_TMPBUF_SZ  256
+
+/*
+ * Maintain state of copy progress.
+ */
+struct boot_status {
+    uint32_t idx;       /* Which area we're operating on */
+    uint8_t state;      /* Which part of the swapping process are we at */
+};
+
+#define BOOT_MAGIC_GOOD  1
+#define BOOT_MAGIC_BAD   2
+#define BOOT_MAGIC_UNSET 3
+
+/**
+ * End-of-image slot structure.
+ *
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * ~                        MAGIC (16 octets)                      ~
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * ~                                                               ~
+ * ~                Swap status (variable, aligned)                ~
+ * ~                                                               ~
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Copy done   |     0xff padding (up to min-write-sz - 1)     ~
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Image OK    |     0xff padding (up to min-write-sz - 1)     ~
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+
+extern const uint32_t boot_img_magic[4];
+
+struct boot_swap_state {
+    uint8_t magic;  /* One of the BOOT_MAGIC_[...] values. */
+    uint8_t copy_done;
+    uint8_t image_ok;
+};
+
+#define BOOT_STATUS_STATE_COUNT 3
+#define BOOT_STATUS_MAX_ENTRIES 128
+
+#define BOOT_STATUS_SOURCE_NONE    0
+#define BOOT_STATUS_SOURCE_SCRATCH 1
+#define BOOT_STATUS_SOURCE_SLOT0   2
+
+int bootutil_verify_sig(uint8_t *hash, uint32_t hlen, uint8_t *sig, int slen,
+    uint8_t key_id);
+
+uint32_t boot_trailer_sz(uint8_t min_write_sz);
+uint32_t boot_status_off(const struct flash_area *fap);
+int boot_read_swap_state(const struct flash_area *fap,
+                         struct boot_swap_state *state);
+int boot_read_swap_state_img(int slot, struct boot_swap_state *state);
+int boot_read_swap_state_scratch(struct boot_swap_state *state);
+int boot_write_magic(const struct flash_area *fap);
+int boot_write_status(struct boot_status *bs);
+int boot_schedule_test_swap(void);
+int boot_write_copy_done(const struct flash_area *fap);
+int boot_write_image_ok(const struct flash_area *fap);
+
+uint32_t boot_status_sz(uint8_t min_write_sz);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+