+ POLARSSL_ERR_MPI_NOT_ACCEPTABLE if A has no inverse mod N
+ */
+int mpi_inv_mod( mpi *X, const mpi *A, const mpi *N );
+
+/**
+ * \brief Miller-Rabin primality test
+ *
+ * \param X MPI to check
+ * \param f_rng RNG function
+ * \param p_rng RNG parameter
+ *
+ * \return 0 if successful (probably prime),
+ * 1 if memory allocation failed,
+ * POLARSSL_ERR_MPI_NOT_ACCEPTABLE if X is not prime
+ */
+int mpi_is_prime( mpi *X, int (*f_rng)(void *), void *p_rng );
+
+/**
+ * \brief Prime number generation
+ *
+ * \param X Destination MPI
+ * \param nbits Required size of X in bits
+ * \param dh_flag If 1, then (X-1)/2 will be prime too
+ * \param f_rng RNG function
+ * \param p_rng RNG parameter
+ *
+ * \return 0 if successful (probably prime),
+ * 1 if memory allocation failed,
+ * POLARSSL_ERR_MPI_BAD_INPUT_DATA if nbits is < 3