+#elif CONFIG_MBEDTLS
+#define bn_new(bn) \
+ do { \
+ bn = av_malloc(sizeof(*bn)); \
+ if (bn) \
+ mbedtls_mpi_init(bn); \
+ } while (0)
+#define bn_free(bn) \
+ do { \
+ mbedtls_mpi_free(bn); \
+ av_free(bn); \
+ } while (0)
+#define bn_set_word(bn, w) mbedtls_mpi_lset(bn, w)
+#define bn_cmp(a, b) mbedtls_mpi_cmp_mpi(a, b)
+#define bn_copy(to, from) mbedtls_mpi_copy(to, from)
+#define bn_sub_word(bn, w) mbedtls_mpi_sub_int(bn, bn, w)
+#define bn_cmp_1(bn) mbedtls_mpi_cmp_int(bn, 1)
+#define bn_num_bytes(bn) (mbedtls_mpi_bitlen(bn) + 7) / 8
+#define bn_bn2bin(bn, buf, len) mbedtls_mpi_write_binary(bn, buf, len)
+#define bn_bin2bn(bn, buf, len) \
+ do { \
+ bn_new(bn); \
+ if (bn) \
+ mbedtls_mpi_read_binary(bn, buf, len); \
+ } while (0)
+#define bn_hex2bn(bn, buf, ret) \
+ do { \
+ bn_new(bn); \
+ if (bn) \
+ ret = (mbedtls_mpi_read_string(bn, 16, buf) == 0); \
+ else \
+ ret = 1; \
+ } while (0)
+#define bn_random(bn, num_bits) \
+ do { \
+ mbedtls_entropy_context entropy_ctx; \
+ mbedtls_ctr_drbg_context ctr_drbg_ctx; \
+ \
+ mbedtls_entropy_init(&entropy_ctx); \
+ mbedtls_ctr_drbg_init(&ctr_drbg_ctx); \
+ mbedtls_ctr_drbg_seed(&ctr_drbg_ctx, \
+ mbedtls_entropy_func, \
+ &entropy_ctx, \
+ NULL, 0); \
+ mbedtls_mpi_fill_random(bn, (num_bits + 7) / 8, mbedtls_ctr_drbg_random, &ctr_drbg_ctx); \
+ mbedtls_ctr_drbg_free(&ctr_drbg_ctx); \
+ mbedtls_entropy_free(&entropy_ctx); \
+ } while (0)
+#define bn_modexp(bn, y, q, p) mbedtls_mpi_exp_mod(bn, y, q, p, 0)
+