Hi, im using mbedtls 2.7.17 in my project on stm32f417 (168Mhz) with config similar to config-mini-tls1_1.h for server HTTPS support (Keil). mbedtls_rsa_private is executed ~19seconds on key_exchange phase on browser connection. I’m use default embedded test RSA ca, cert and pkey. Compilation with speed optimization  and without not signaficantly reduces this time. Is it normal time of caclulation or something wrong with my platform? I’m expected about 1-2s, not 19..How can i reduce execution time  as an expected? Thanks. #ifndef MBEDTLS_CONFIG_H #define MBEDTLS_CONFIG_H /* System support */ #define MBEDTLS_HAVE_ASM #define MBEDTLS_HAVE_TIME /* mbed TLS feature support */ #define MBEDTLS_CIPHER_MODE_CBC #define MBEDTLS_PKCS1_V15 #define MBEDTLS_KEY_EXCHANGE_RSA_ENABLED #define MBEDTLS_SSL_PROTO_TLS1_1 /* mbed TLS modules */ #define MBEDTLS_AES_C #define MBEDTLS_ASN1_PARSE_C #define MBEDTLS_ASN1_WRITE_C #define MBEDTLS_BIGNUM_C #define MBEDTLS_CIPHER_C #define MBEDTLS_CTR_DRBG_C #define MBEDTLS_DES_C #define MBEDTLS_ENTROPY_C #define MBEDTLS_MD_C #define MBEDTLS_MD5_C //#define MBEDTLS_NET_C #define MBEDTLS_OID_C #define MBEDTLS_PK_C #define MBEDTLS_PK_PARSE_C #define MBEDTLS_RSA_C #define MBEDTLS_SHA1_C #define MBEDTLS_SHA256_C //#define MBEDTLS_SSL_CLI_C #define MBEDTLS_SSL_SRV_C #define MBEDTLS_SSL_TLS_C #define MBEDTLS_X509_CRT_PARSE_C #define MBEDTLS_X509_USE_C /* For test certificates */ #define MBEDTLS_BASE64_C #define MBEDTLS_CERTS_C #define MBEDTLS_PEM_PARSE_C /* For testing with compat.sh */ //#define MBEDTLS_FS_IO #define MBEDTLS_NO_PLATFORM_ENTROPY   #include "mbedtls/check_config.h" #endif /* MBEDTLS_CONFIG_H */   -- Dmitry X