+ gc_malloc_t secure_malloc,
+ gc_secure_check_t secure_check,
+ gc_realloc_t func_realloc,
+ gc_free_t func_free);
+
+/* 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);
+
+/* Hashes. */
+
+extern Gc_rc gc_hash_open (Gc_hash hash, Gc_hash_mode mode,
+ gc_hash_handle *outhandle);
+extern Gc_rc gc_hash_clone (gc_hash_handle handle, gc_hash_handle *outhandle);
+extern size_t gc_hash_digest_length (Gc_hash hash);
+extern void gc_hash_hmac_setkey (gc_hash_handle handle,
+ size_t len, const char *key);
+extern void gc_hash_write (gc_hash_handle handle,
+ size_t len, const char *data);
+extern const char *gc_hash_read (gc_hash_handle handle);
+extern void gc_hash_close (gc_hash_handle handle);
+
+/* Compute a hash value over buffer IN of INLEN bytes size using the
+ algorithm HASH, placing the result in the pre-allocated buffer OUT.
+ The required size of OUT depends on HASH, and is generally
+ GC_<HASH>_DIGEST_SIZE. For example, for GC_MD5 the output buffer
+ must be 16 bytes. The return value is 0 (GC_OK) on success, or
+ another Gc_rc error code. */
+extern Gc_rc
+gc_hash_buffer (Gc_hash hash, const void *in, size_t inlen, char *out);