-int nonce2key(uint32_t uid, uint32_t nt, uint32_t nr, uint64_t par_info, uint64_t ks_info, uint64_t * key);
-
-int nonce2key_ex(uint32_t uid, uint32_t nt, uint32_t nr, uint64_t ks_info, uint64_t * key);
+extern int nonce2key(uint32_t uid, uint32_t nt, uint32_t nr, uint64_t par_info, uint64_t ks_info, uint64_t * key);
+extern int nonce2key_ex(uint32_t uid, uint32_t nt, uint32_t nr, uint64_t ks_info, uint64_t * key);