diff --git a/minelf/Retouch.h b/minelf/Retouch.h
new file mode 100644
index 0000000..048d78e
--- /dev/null
+++ b/minelf/Retouch.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed 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 _MINELF_RETOUCH
+#define _MINELF_RETOUCH
+
+#include <stdbool.h>
+#include <sys/types.h>
+
+typedef struct {
+  char tag[8];        /* "RETOUCH ", not zero-terminated */
+  uint32_t blob_size; /* in bytes, located right before this struct */
+} retouch_info_t __attribute__((packed));
+
+// Retouch a file. Use CACHED_SOURCE_TEMP to store a copy.
+bool retouch_one_library(const char *binary_name,
+                         const char *binary_sha1,
+                         int32_t retouch_offset,
+                         int32_t *retouch_offset_override);
+
+#define RETOUCH_DONT_MASK           0
+#define RETOUCH_DO_MASK             1
+
+#define RETOUCH_DATA_ERROR          0 // This is bad. Should not happen.
+#define RETOUCH_DATA_MATCHED        1 // Up to an uniform random offset.
+#define RETOUCH_DATA_MISMATCHED     2 // Partially randomized, or total mess.
+#define RETOUCH_DATA_NOTAPPLICABLE  3 // Not retouched. Only when inferring.
+
+// Mask retouching in-memory. Used before apply_patch[_check].
+// Also used to determine status of retouching after a crash.
+//
+// If desired_offset is not NULL, then apply retouching instead,
+// and return that in retouch_offset.
+int retouch_mask_data(uint8_t *binary_object,
+                      int32_t binary_size,
+                      int32_t *desired_offset,
+                      int32_t *retouch_offset);
+#endif