diff --git a/src/ber_decoder.h b/src/ber_decoder.h
new file mode 100644
index 0000000..768133b
--- /dev/null
+++ b/src/ber_decoder.h
@@ -0,0 +1,63 @@
+/*-
+ * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef	_BER_DECODER_H_
+#define	_BER_DECODER_H_
+
+#include <asn_application.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct asn_TYPE_descriptor_s;	/* Forward declaration */
+struct asn_codec_ctx_s;		/* Forward declaration */
+
+/*
+ * The BER decoder of any type.
+ * This function may be invoked directly from the application.
+ */
+asn_dec_rval_t ber_decode(struct asn_codec_ctx_s *opt_codec_ctx,
+	struct asn_TYPE_descriptor_s *type_descriptor,
+	void **struct_ptr,	/* Pointer to a target structure's pointer */
+	const void *buffer,	/* Data to be decoded */
+	size_t size		/* Size of that buffer */
+	);
+
+/*
+ * Type of generic function which decodes the byte stream into the structure.
+ */
+typedef asn_dec_rval_t (ber_type_decoder_f)(
+		struct asn_codec_ctx_s *opt_codec_ctx,
+		struct asn_TYPE_descriptor_s *type_descriptor,
+		void **struct_ptr, const void *buf_ptr, size_t size,
+		int tag_mode);
+
+/*******************************
+ * INTERNALLY USEFUL FUNCTIONS *
+ *******************************/
+
+/*
+ * Check that all tags correspond to the type definition (as given in head).
+ * On return, last_length would contain either a non-negative length of the
+ * value part of the last TLV, or the negative number of expected
+ * "end of content" sequences. The number may only be negative if the
+ * head->last_tag_form is non-zero.
+ */
+asn_dec_rval_t ber_check_tags(
+		struct asn_codec_ctx_s *opt_codec_ctx,	/* codec options */
+		struct asn_TYPE_descriptor_s *type_descriptor,
+		asn_struct_ctx_t *opt_ctx,	/* saved decoding context */
+		const void *ptr, size_t size,
+		int tag_mode,		/* {-1,0,1}: IMPLICIT, no, EXPLICIT */
+		int last_tag_form,	/* {-1,0:1}: any, primitive, constr */
+		ber_tlv_len_t *last_length,
+		int *opt_tlv_form	/* optional tag form */
+	);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* _BER_DECODER_H_ */