-int key_sign(Key *, u_char **, u_int *, u_char *, u_int);
-int key_verify(Key *, u_char *, u_int, u_char *, u_int);
+int key_sign(const Key *, u_char **, u_int *, const u_char *, u_int);
+int key_verify(const Key *, const u_char *, u_int, const u_char *, u_int);
+
+int ssh_dss_sign(const Key *, u_char **, u_int *, const u_char *, u_int);
+int ssh_dss_verify(const Key *, const u_char *, u_int, const u_char *, u_int);
+int ssh_rsa_sign(const Key *, u_char **, u_int *, const u_char *, u_int);
+int ssh_rsa_verify(const Key *, const u_char *, u_int, const u_char *, u_int);