+/*
+ * Get the encoded OID for a given hash function (to use with PKCS#1
+ * signatures). If the hash function ID is 0 (for MD5+SHA-1), or if
+ * the ID is not one of the SHA-* functions (SHA-1, SHA-224, SHA-256,
+ * SHA-384, SHA-512), then this function returns NULL.
+ */
+const unsigned char *get_hash_oid(int id);
+
+/*
+ * Get a hash implementation by ID. This returns NULL if the hash
+ * implementation is not available.
+ */
+const br_hash_class *get_hash_impl(int id);
+