+/* Randomness. */
+extern Gc_rc gc_nonce (char *data, size_t datalen);
+extern Gc_rc gc_pseudo_random (char *data, size_t datalen);
+extern Gc_rc gc_random (char *data, size_t datalen);
+
+/* Ciphers. */
+extern Gc_rc gc_cipher_open (Gc_cipher cipher, Gc_cipher_mode mode,
+ gc_cipher_handle *outhandle);
+extern Gc_rc gc_cipher_setkey (gc_cipher_handle handle,
+ size_t keylen, const char *key);
+extern Gc_rc gc_cipher_setiv (gc_cipher_handle handle,
+ size_t ivlen, const char *iv);
+extern Gc_rc gc_cipher_encrypt_inline (gc_cipher_handle handle,
+ size_t len, char *data);
+extern Gc_rc gc_cipher_decrypt_inline (gc_cipher_handle handle,
+ size_t len, char *data);
+extern Gc_rc gc_cipher_close (gc_cipher_handle handle);
+