diff --git a/src/der_encoder.h b/src/der_encoder.h
new file mode 100644
index 0000000..4e2fb06
--- /dev/null
+++ b/src/der_encoder.h
@@ -0,0 +1,67 @@
+/*-
+ * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef	_DER_ENCODER_H_
+#define	_DER_ENCODER_H_
+
+#include <asn_application.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct asn_TYPE_descriptor_s;	/* Forward declaration */
+
+/*
+ * The DER encoder of any type. May be invoked by the application.
+ */
+asn_enc_rval_t der_encode(struct asn_TYPE_descriptor_s *type_descriptor,
+		void *struct_ptr,	/* Structure to be encoded */
+		asn_app_consume_bytes_f *consume_bytes_cb,
+		void *app_key		/* Arbitrary callback argument */
+	);
+
+/* A variant of der_encode() which encodes data into the pre-allocated buffer */
+asn_enc_rval_t der_encode_to_buffer(
+		struct asn_TYPE_descriptor_s *type_descriptor,
+		void *struct_ptr,	/* Structure to be encoded */
+		void *buffer,		/* Pre-allocated buffer */
+		size_t buffer_size	/* Initial buffer size (maximum) */
+	);
+
+/*
+ * Type of the generic DER encoder.
+ */
+typedef asn_enc_rval_t (der_type_encoder_f)(
+		struct asn_TYPE_descriptor_s *type_descriptor,
+		void *struct_ptr,	/* Structure to be encoded */
+		int tag_mode,		/* {-1,0,1}: IMPLICIT, no, EXPLICIT */
+		ber_tlv_tag_t tag,
+		asn_app_consume_bytes_f *consume_bytes_cb,	/* Callback */
+		void *app_key		/* Arbitrary callback argument */
+	);
+
+
+/*******************************
+ * INTERNALLY USEFUL FUNCTIONS *
+ *******************************/
+
+/*
+ * Write out leading TL[v] sequence according to the type definition.
+ */
+ssize_t der_write_tags(
+		struct asn_TYPE_descriptor_s *type_descriptor,
+		size_t struct_length,
+		int tag_mode,		/* {-1,0,1}: IMPLICIT, no, EXPLICIT */
+		int last_tag_form,	/* {0,!0}: prim, constructed */
+		ber_tlv_tag_t tag,
+		asn_app_consume_bytes_f *consume_bytes_cb,
+		void *app_key
+	);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* _DER_ENCODER_H_ */