diff --git a/cli.c b/cli.c
index 9d1ea003..2013f262 100644
--- a/cli.c
+++ b/cli.c
@@ -25,6 +25,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "serval.h"
 #include "rhizome.h"
 #include "strbuf_helpers.h"
+#include "dataformats.h"
 
 int cli_usage(const struct cli_schema *commands, XPRINTF xpf)
 {
diff --git a/commandline.c b/commandline.c
index ab474b41..e579d982 100644
--- a/commandline.c
+++ b/commandline.c
@@ -46,6 +46,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "overlay_address.h"
 #include "overlay_buffer.h"
 #include "keyring.h"
+#include "dataformats.h"
 
 extern struct cli_schema command_line_options[];
 
diff --git a/conf_schema.c b/conf_schema.c
index 02348b8a..c53c74f5 100644
--- a/conf_schema.c
+++ b/conf_schema.c
@@ -32,6 +32,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "strbuf.h"
 #include "strbuf_helpers.h"
 #include "conf.h"
+#include "dataformats.h"
 
 int cf_opt_boolean(bool_t *booleanp, const char *text)
 {
diff --git a/dataformats.c b/dataformats.c
index 5180775d..ed841ca2 100644
--- a/dataformats.c
+++ b/dataformats.c
@@ -17,10 +17,11 @@ along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
 
+#include <ctype.h>
 #include "serval.h"
 #include "rhizome.h"
 #include "str.h"
-#include <ctype.h>
+#include "dataformats.h"
 
 int cmp_sid_t(const sid_t *a, const sid_t *b)
 {
@@ -214,7 +215,7 @@ void write_uint16(unsigned char *o,uint16_t v)
   { *(o++)=v&0xff; v=v>>8; }
 }
 
-uint64_t read_uint64(unsigned char *o)
+uint64_t read_uint64(const unsigned char *o)
 {
   int i;
   uint64_t v=0;
@@ -222,7 +223,7 @@ uint64_t read_uint64(unsigned char *o)
   return v;
 }
 
-uint32_t read_uint32(unsigned char *o)
+uint32_t read_uint32(const unsigned char *o)
 {
   int i;
   uint32_t v=0;
@@ -230,7 +231,7 @@ uint32_t read_uint32(unsigned char *o)
   return v;
 }
 
-uint16_t read_uint16(unsigned char *o)
+uint16_t read_uint16(const unsigned char *o)
 {
   int i;
   uint16_t v=0;
diff --git a/dataformats.h b/dataformats.h
new file mode 100644
index 00000000..67afb746
--- /dev/null
+++ b/dataformats.h
@@ -0,0 +1,26 @@
+#ifndef __SERVALD_DATA_FORMATS_H
+#define __SERVALD_DATA_FORMATS_H
+
+int str_is_subscriber_id(const char *sid);
+int strn_is_subscriber_id(const char *sid, size_t *lenp);
+int str_is_did(const char *did);
+int strn_is_did(const char *did, size_t *lenp);
+
+int rhizome_strn_is_manifest_id(const char *text);
+int rhizome_str_is_manifest_id(const char *text);
+int rhizome_strn_is_bundle_key(const char *text);
+int rhizome_str_is_bundle_key(const char *text);
+int rhizome_strn_is_bundle_crypt_key(const char *text);
+int rhizome_str_is_bundle_crypt_key(const char *text);
+int rhizome_strn_is_file_hash(const char *text);
+int rhizome_str_is_file_hash(const char *text);
+int rhizome_str_is_manifest_service(const char *text);
+
+void write_uint64(unsigned char *o,uint64_t v);
+void write_uint16(unsigned char *o,uint16_t v);
+void write_uint32(unsigned char *o,uint32_t v);
+uint64_t read_uint64(const unsigned char *o);
+uint32_t read_uint32(const unsigned char *o);
+uint16_t read_uint16(const unsigned char *o);
+
+#endif
diff --git a/dna_helper.c b/dna_helper.c
index d1d18b42..66bceb96 100644
--- a/dna_helper.c
+++ b/dna_helper.c
@@ -27,6 +27,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "strbuf.h"
 #include "strbuf_helpers.h"
 #include "overlay_address.h"
+#include "dataformats.h"
 
 /*
   The challenge with making an interface for calling an external program to 
diff --git a/headerfiles.mk b/headerfiles.mk
index 08a0b2e4..fc9ae543 100644
--- a/headerfiles.mk
+++ b/headerfiles.mk
@@ -19,6 +19,7 @@ HDRS=	fifo.h \
 	conf.h \
 	conf_schema.h \
 	crypto.h \
+	dataformats.h \
 	log.h \
 	net.h \
 	fdqueue.h \
diff --git a/keyring.c b/keyring.c
index 9d0df5c6..3182e6bb 100644
--- a/keyring.c
+++ b/keyring.c
@@ -30,6 +30,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "crypto.h"
 #include "overlay_packet.h"
 #include "keyring.h"
+#include "dataformats.h"
 
 static void keyring_free_keypair(keypair *kp);
 static void keyring_free_context(keyring_context *c);
diff --git a/meshms.c b/meshms.c
index c88a984b..3c3d18ca 100644
--- a/meshms.c
+++ b/meshms.c
@@ -6,6 +6,7 @@
 #include "crypto.h"
 #include "strlcpy.h"
 #include "keyring.h"
+#include "dataformats.h"
 
 #define MESHMS_BLOCK_TYPE_ACK 0x01
 #define MESHMS_BLOCK_TYPE_MESSAGE 0x02
diff --git a/monitor.c b/monitor.c
index 20a710e8..e28016d9 100644
--- a/monitor.c
+++ b/monitor.c
@@ -33,6 +33,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "overlay_address.h"
 #include "monitor-client.h"
 #include "socket.h"
+#include "dataformats.h"
 
 #ifdef HAVE_UCRED_H
 #include <ucred.h>
diff --git a/overlay_mdp_services.c b/overlay_mdp_services.c
index 3c1fbc57..2abc30d4 100644
--- a/overlay_mdp_services.c
+++ b/overlay_mdp_services.c
@@ -29,6 +29,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "crypto.h"
 #include "log.h"
 #include "keyring.h"
+#include "dataformats.h"
 
 int rhizome_mdp_send_block(struct subscriber *dest, const rhizome_bid_t *bid, uint64_t version, uint64_t fileOffset, uint32_t bitmap, uint16_t blockLength)
 {
diff --git a/rhizome.c b/rhizome.c
index 3db8cfc5..68495b3b 100644
--- a/rhizome.c
+++ b/rhizome.c
@@ -23,6 +23,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "conf.h"
 #include "str.h"
 #include "rhizome.h"
+#include "dataformats.h"
 
 int is_rhizome_enabled()
 {
diff --git a/rhizome.h b/rhizome.h
index a45cd823..d99f900a 100644
--- a/rhizome.h
+++ b/rhizome.h
@@ -423,16 +423,6 @@ int rhizome_cleanup(struct rhizome_cleanup_report *report);
 int rhizome_manifest_createid(rhizome_manifest *m);
 int rhizome_get_bundle_from_seed(rhizome_manifest *m, const char *seed);
 
-int rhizome_strn_is_manifest_id(const char *text);
-int rhizome_str_is_manifest_id(const char *text);
-int rhizome_strn_is_bundle_key(const char *text);
-int rhizome_str_is_bundle_key(const char *text);
-int rhizome_strn_is_bundle_crypt_key(const char *text);
-int rhizome_str_is_bundle_crypt_key(const char *text);
-int rhizome_strn_is_file_hash(const char *text);
-int rhizome_str_is_file_hash(const char *text);
-int rhizome_str_is_manifest_service(const char *text);
-
 int is_http_header_complete(const char *buf, size_t len, size_t read_since_last_call);
 
 typedef struct sqlite_retry_state {
diff --git a/rhizome_bundle.c b/rhizome_bundle.c
index 8ecf5b51..a8949032 100644
--- a/rhizome_bundle.c
+++ b/rhizome_bundle.c
@@ -26,6 +26,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "str.h"
 #include "mem.h"
 #include "keyring.h"
+#include "dataformats.h"
 
 static const char *rhizome_manifest_get(const rhizome_manifest *m, const char *var)
 {
diff --git a/rhizome_crypto.c b/rhizome_crypto.c
index 3055204f..fc2868f5 100644
--- a/rhizome_crypto.c
+++ b/rhizome_crypto.c
@@ -23,13 +23,13 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 #include "crypto_sign_edwards25519sha512batch.h"
 #include "nacl/src/crypto_sign_edwards25519sha512batch_ref/ge.h"
-
 #include "serval.h"
 #include "conf.h"
 #include "str.h"
 #include "rhizome.h"
 #include "crypto.h"
 #include "keyring.h"
+#include "dataformats.h"
 
 /* Work out the encrypt/decrypt key for the supplied manifest.
    If the manifest is not encrypted, then return NULL.
diff --git a/rhizome_fetch.c b/rhizome_fetch.c
index 6546fd4e..d2614b10 100644
--- a/rhizome_fetch.c
+++ b/rhizome_fetch.c
@@ -27,6 +27,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "strbuf_helpers.h"
 #include "overlay_address.h"
 #include "socket.h"
+#include "dataformats.h"
 
 /* Represents a queued fetch of a bundle payload, for which the manifest is already known.
  */
diff --git a/serval.h b/serval.h
index 983e0daf..a84d5e81 100644
--- a/serval.h
+++ b/serval.h
@@ -163,11 +163,6 @@ int cmp_sid_t(const sid_t *a, const sid_t *b);
 int str_to_sid_t(sid_t *sid, const char *hex);
 int strn_to_sid_t(sid_t *sid, const char *hex, const char **endp);
 
-int str_is_subscriber_id(const char *sid);
-int strn_is_subscriber_id(const char *sid, size_t *lenp);
-int str_is_did(const char *did);
-int strn_is_did(const char *did, size_t *lenp);
-
 #define alloca_tohex_sas(sas)           alloca_tohex((sas), SAS_SIZE)
 
 /*
@@ -686,13 +681,6 @@ int limit_init(struct limit_state *state, int rate_micro_seconds);
 int olsr_init_socket(void);
 int olsr_send(struct overlay_frame *frame);
 
-void write_uint64(unsigned char *o,uint64_t v);
-void write_uint16(unsigned char *o,uint16_t v);
-void write_uint32(unsigned char *o,uint32_t v);
-uint64_t read_uint64(unsigned char *o);
-uint32_t read_uint32(unsigned char *o);
-uint16_t read_uint16(unsigned char *o);
-
 int pack_uint(unsigned char *buffer, uint64_t v);
 int measure_packed_uint(uint64_t v);
 int unpack_uint(unsigned char *buffer, int buff_size, uint64_t *v);
diff --git a/slip.c b/slip.c
index daa37052..134d3e39 100644
--- a/slip.c
+++ b/slip.c
@@ -20,6 +20,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "serval.h"
 #include "conf.h"
 #include "log.h"
+#include "dataformats.h"
 
 #define DEBUG_packet_visualise(M,P,N) logServalPacket(LOG_LEVEL_DEBUG, __WHENCE__, (M), (P), (N))