esp-idf/components/mbedtls/Kconfig

menu "mbedTLS"

choice MBEDTLS_MEM_ALLOC_MODE
    prompt "Memory allocation strategy"
    default MBEDTLS_INTERNAL_MEM_ALLOC
    help
        Allocation strategy for mbedTLS, essentially provides ability to
        allocate all required dynamic allocations from,

            - Internal DRAM memory only
            - External SPIRAM memory only
            - Either internal or external memory based on default malloc()
              behavior in ESP-IDF
            - Custom allocation mode, by overwriting calloc()/free() using
              mbedtls_platform_set_calloc_free() function

        Recommended mode here is always internal, since that is most preferred
        from security perspective. But if application requirement does not
        allow sufficient free internal memory then alternate mode can be
        selected.

config MBEDTLS_INTERNAL_MEM_ALLOC
    bool "Internal memory"

config MBEDTLS_EXTERNAL_MEM_ALLOC
    bool "External SPIRAM"
    depends on SPIRAM_SUPPORT

config MBEDTLS_DEFAULT_MEM_ALLOC
    bool "Default alloc mode"

config MBEDTLS_CUSTOM_MEM_ALLOC
    bool "Custom alloc mode"

endchoice #MBEDTLS_MEM_ALLOC_MODE

config MBEDTLS_SSL_MAX_CONTENT_LEN
    int "TLS maximum message content length"
    default 16384
    range 512 16384
    depends on !MBEDTLS_ASYMMETRIC_CONTENT_LEN
    help
        Maximum TLS message length (in bytes) supported by mbedTLS.
        
        16384 is the default and this value is required to comply
        fully with TLS standards.
        
        However you can set a lower value in order to save RAM. This
        is safe if the other end of the connection supports Maximum
        Fragment Length Negotiation Extension (max_fragment_length,
        see RFC6066) or you know for certain that it will never send a
        message longer than a certain number of bytes.

        If the value is set too low, symptoms are a failed TLS
        handshake or a return value of MBEDTLS_ERR_SSL_INVALID_RECORD
        (-0x7200).

config MBEDTLS_ASYMMETRIC_CONTENT_LEN
    bool "Asymmetric in/out fragment length"
    default n
    help
       If enabled, this option allows customizing TLS in/out fragment length
       in asymmetric way. Please note that enabling this with default values
       saves 12KB of dynamic memory per TLS connection.

config MBEDTLS_SSL_IN_CONTENT_LEN
    int "TLS maximum incoming fragment length"
    default 16384
    range 512 16384
    depends on MBEDTLS_ASYMMETRIC_CONTENT_LEN
    help
        This defines maximum incoming fragment length, overriding default
        maximum content length (MBEDTLS_SSL_MAX_CONTENT_LEN).

config MBEDTLS_SSL_OUT_CONTENT_LEN
    int "TLS maximum outgoing fragment length"
    default 4096
    range 512 16384
    depends on MBEDTLS_ASYMMETRIC_CONTENT_LEN
    help
        This defines maximum outgoing fragment length, overriding default
        maximum content length (MBEDTLS_SSL_MAX_CONTENT_LEN).

config MBEDTLS_DEBUG
   bool "Enable mbedTLS debugging"
   default n
   help
       Enable mbedTLS debugging functions at compile time.

       If this option is enabled, you can include
	   "mbedtls/esp_debug.h" and call mbedtls_esp_enable_debug_log()
	   at runtime in order to enable mbedTLS debug output via the ESP
	   log mechanism.

config MBEDTLS_HARDWARE_AES
   bool "Enable hardware AES acceleration"
   default y
   help
       Enable hardware accelerated AES encryption & decryption.

       Note that if the ESP32 CPU is running at 240MHz, hardware AES does not
       offer any speed boost over software AES.

config MBEDTLS_HARDWARE_MPI
   bool "Enable hardware MPI (bignum) acceleration"
   default n
   help
       Enable hardware accelerated multiple precision integer operations.

       Hardware accelerated multiplication, modulo multiplication,
       and modular exponentiation for up to 4096 bit results.

       These operations are used by RSA.

config MBEDTLS_MPI_USE_INTERRUPT
    bool "Use interrupt for MPI operations"
    depends on MBEDTLS_HARDWARE_MPI
    default n
    help
        Use an interrupt to coordinate MPI operations.

        This allows other code to run on the CPU while an MPI operation is pending.
        Otherwise the CPU busy-waits.

config MBEDTLS_HARDWARE_SHA
   bool "Enable hardware SHA acceleration"
   default n
   help
       Enable hardware accelerated SHA1, SHA256, SHA384 & SHA512 in mbedTLS.

       Due to a hardware limitation, hardware acceleration is only
       guaranteed if SHA digests are calculated one at a time. If more
       than one SHA digest is calculated at the same time, one will
       be calculated fully in hardware and the rest will be calculated
       (at least partially calculated) in software. This happens automatically.

       SHA hardware acceleration is faster than software in some situations but
       slower in others. You should benchmark to find the best setting for you.

config MBEDTLS_HAVE_TIME
   bool "Enable mbedtls time"
   depends on !ESP32_TIME_SYSCALL_USE_NONE
   default y
   help
       System has time.h and time().
       The time does not need to be correct, only time differences are used.

config MBEDTLS_HAVE_TIME_DATE
   bool "Enable mbedtls certificate expiry check"
   depends on MBEDTLS_HAVE_TIME
   default n
   help
       System has time.h and time(), gmtime() and the clock is correct.
       The time needs to be correct (not necesarily very accurate, but at least
       the date should be correct). This is used to verify the validity period of
       X.509 certificates.

       It is suggested that you should get the real time by "SNTP".

choice MBEDTLS_TLS_MODE
    bool "TLS Protocol Role"
    default MBEDTLS_TLS_SERVER_AND_CLIENT
    help
        mbedTLS can be compiled with protocol support for the TLS
        server, TLS client, or both server and client.

        Reducing the number of TLS roles supported saves code size.

config MBEDTLS_TLS_SERVER_AND_CLIENT
    bool "Server & Client"
    select MBEDTLS_TLS_SERVER
    select MBEDTLS_TLS_CLIENT
config MBEDTLS_TLS_SERVER_ONLY
    bool "Server"
    select MBEDTLS_TLS_SERVER
config MBEDTLS_TLS_CLIENT_ONLY
    bool "Client"
    select MBEDTLS_TLS_CLIENT
config MBEDTLS_TLS_DISABLED
    bool "None"

endchoice

config MBEDTLS_TLS_SERVER
    bool
    select MBEDTLS_TLS_ENABLED
config MBEDTLS_TLS_CLIENT
    bool
    select MBEDTLS_TLS_ENABLED
config MBEDTLS_TLS_ENABLED
    bool

menu "TLS Key Exchange Methods"
   depends on MBEDTLS_TLS_ENABLED

config MBEDTLS_PSK_MODES
   bool "Enable pre-shared-key ciphersuites"
   default n
   help
       Enable to show configuration for different types of pre-shared-key TLS authentatication methods.

       Leaving this options disabled will save code size if they are not used.

config MBEDTLS_KEY_EXCHANGE_PSK
   bool "Enable PSK based ciphersuite modes"
   depends on MBEDTLS_PSK_MODES
   default n
   help
       Enable to support symmetric key PSK (pre-shared-key) TLS key exchange modes.

config MBEDTLS_KEY_EXCHANGE_DHE_PSK
   bool "Enable DHE-PSK based ciphersuite modes"
   depends on MBEDTLS_PSK_MODES
   default y
   help
       Enable to support Diffie-Hellman PSK (pre-shared-key) TLS authentication modes.

config MBEDTLS_KEY_EXCHANGE_ECDHE_PSK
   bool "Enable ECDHE-PSK based ciphersuite modes"
   depends on MBEDTLS_PSK_MODES
   default y
   help
       Enable to support Elliptic-Curve-Diffie-Hellman PSK (pre-shared-key) TLS authentication modes.

config MBEDTLS_KEY_EXCHANGE_RSA_PSK
   bool "Enable RSA-PSK based ciphersuite modes"
   depends on MBEDTLS_PSK_MODES
   default y
   help
       Enable to support RSA PSK (pre-shared-key) TLS authentication modes.

config MBEDTLS_KEY_EXCHANGE_RSA
   bool "Enable RSA-only based ciphersuite modes"
   default y
   help
       Enable to support ciphersuites with prefix TLS-RSA-WITH-

config MBEDTLS_KEY_EXCHANGE_DHE_RSA
   bool "Enable DHE-RSA based ciphersuite modes"
   default y
   help
       Enable to support ciphersuites with prefix TLS-DHE-RSA-WITH-

config MBEDTLS_KEY_EXCHANGE_ELLIPTIC_CURVE
   bool "Support Elliptic Curve based ciphersuites"
   depends on MBEDTLS_ECP_C
   default y
   help
       Enable to show Elliptic Curve based ciphersuite mode options.

       Disabling all Elliptic Curve ciphersuites saves code size and
       can give slightly faster TLS handshakes, provided the server supports
       RSA-only ciphersuite modes.

config MBEDTLS_KEY_EXCHANGE_ECDHE_RSA
   bool "Enable ECDHE-RSA based ciphersuite modes"
   depends on MBEDTLS_KEY_EXCHANGE_ELLIPTIC_CURVE && MBEDTLS_ECDH_C
   default y
   help
       Enable to support ciphersuites with prefix TLS-ECDHE-RSA-WITH-

config MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA
   bool "Enable ECDHE-ECDSA based ciphersuite modes"
   depends on MBEDTLS_KEY_EXCHANGE_ELLIPTIC_CURVE && MBEDTLS_ECDH_C && MBEDTLS_ECDSA_C
   default y
   help
       Enable to support ciphersuites with prefix TLS-ECDHE-RSA-WITH-

config MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA
   bool "Enable ECDH-ECDSA based ciphersuite modes"
   depends on MBEDTLS_KEY_EXCHANGE_ELLIPTIC_CURVE && MBEDTLS_ECDH_C && MBEDTLS_ECDSA_C
   default y
   help
       Enable to support ciphersuites with prefix TLS-ECDHE-RSA-WITH-

config MBEDTLS_KEY_EXCHANGE_ECDH_RSA
   bool "Enable ECDH-RSA based ciphersuite modes"
   depends on MBEDTLS_KEY_EXCHANGE_ELLIPTIC_CURVE && MBEDTLS_ECDH_C
   default y
   help
       Enable to support ciphersuites with prefix TLS-ECDHE-RSA-WITH-

endmenu # TLS key exchange modes

config MBEDTLS_SSL_RENEGOTIATION
   bool "Support TLS renegotiation"
   depends on MBEDTLS_TLS_ENABLED
   default y
   help
       The two main uses of renegotiation are (1) refresh keys on long-lived
       connections and (2) client authentication after the initial handshake.
       If you don't need renegotiation, disabling it will save code size and
       reduce the possibility of abuse/vulnerability.

config MBEDTLS_SSL_PROTO_SSL3
   bool "Legacy SSL 3.0 support"
   depends on MBEDTLS_TLS_ENABLED
   default n
   help
       Support the legacy SSL 3.0 protocol. Most servers will speak a newer
       TLS protocol these days.

config MBEDTLS_SSL_PROTO_TLS1
   bool "Support TLS 1.0 protocol"
   depends on MBEDTLS_TLS_ENABLED
   default y

config MBEDTLS_SSL_PROTO_TLS1_1
   bool "Support TLS 1.1 protocol"
   depends on MBEDTLS_TLS_ENABLED
   default y

config MBEDTLS_SSL_PROTO_TLS1_2
   bool "Support TLS 1.2 protocol"
   depends on MBEDTLS_TLS_ENABLED
   default y

config MBEDTLS_SSL_PROTO_DTLS
   bool "Support DTLS protocol (all versions)"
   default n
   depends on MBEDTLS_SSL_PROTO_TLS1_1 || MBEDTLS_SSL_PROTO_TLS1_2
   help
       Requires TLS 1.1 to be enabled for DTLS 1.0
       Requires TLS 1.2 to be enabled for DTLS 1.2

config MBEDTLS_SSL_ALPN
   bool "Support ALPN (Application Layer Protocol Negotiation)"
   depends on MBEDTLS_TLS_ENABLED
   default y
   help
       Disabling this option will save some code size if it is not needed.

config MBEDTLS_SSL_SESSION_TICKETS
   bool "TLS: Support RFC 5077 SSL session tickets"
   default y
   depends on MBEDTLS_TLS_ENABLED
   help
       Support RFC 5077 session tickets. See mbedTLS documentation for more details.

       Disabling this option will save some code size.

menu "Symmetric Ciphers"

config MBEDTLS_AES_C
   bool "AES block cipher"
   default y

config MBEDTLS_CAMELLIA_C
   bool "Camellia block cipher"
   default n

config MBEDTLS_DES_C
   bool "DES block cipher (legacy, insecure)"
   default n
   help
       Enables the DES block cipher to support 3DES-based TLS ciphersuites.

       3DES is vulnerable to the Sweet32 attack and should only be enabled
       if absolutely necessary.

choice MBEDTLS_RC4_MODE
    prompt "RC4 Stream Cipher (legacy, insecure)"
    default MBEDTLS_RC4_DISABLED
    help
        ARCFOUR (RC4) stream cipher can be disabled entirely, enabled but not
        added to default ciphersuites, or enabled completely.

        Please consider the security implications before enabling RC4.

config MBEDTLS_RC4_DISABLED
    bool "Disabled"
config MBEDTLS_RC4_ENABLED_NO_DEFAULT
    bool "Enabled, not in default ciphersuites"
config MBEDTLS_RC4_ENABLED
    bool "Enabled"
endchoice

config MBEDTLS_BLOWFISH_C
    bool "Blowfish block cipher (read help)"
    default n
    help
        Enables the Blowfish block cipher (not used for TLS sessions.)

        The Blowfish cipher is not used for mbedTLS TLS sessions but can be
        used for other purposes. Read up on the limitations of Blowfish (including
        Sweet32) before enabling.

config MBEDTLS_XTEA_C
    bool "XTEA block cipher"
    default n
    help
        Enables the XTEA block cipher.


config MBEDTLS_CCM_C
    bool "CCM (Counter with CBC-MAC) block cipher modes"
    default y
    depends on MBEDTLS_AES_C || MBEDTLS_CAMELLIA_C
    help
        Enable Counter with CBC-MAC (CCM) modes for AES and/or Camellia ciphers.

        Disabling this option saves some code size.

config MBEDTLS_GCM_C
    bool "GCM (Galois/Counter) block cipher modes"
    default y
    depends on MBEDTLS_AES_C || MBEDTLS_CAMELLIA_C
    help
        Enable Galois/Counter Mode for AES and/or Camellia ciphers.

        This option is generally faster than CCM.

endmenu # Symmetric Ciphers

config MBEDTLS_RIPEMD160_C
    bool "Enable RIPEMD-160 hash algorithm"
    default n
    help
        Enable the RIPEMD-160 hash algorithm.

menu "Certificates"

config MBEDTLS_PEM_PARSE_C
    bool "Read & Parse PEM formatted certificates"
    default y
    help
        Enable decoding/parsing of PEM formatted certificates.

        If your certificates are all in the simpler DER format, disabling
        this option will save some code size.

config MBEDTLS_PEM_WRITE_C
    bool "Write PEM formatted certificates"
    default y
    help
        Enable writing of PEM formatted certificates.

        If writing certificate data only in DER format, disabling this
        option will save some code size.

config MBEDTLS_X509_CRL_PARSE_C
    bool "X.509 CRL parsing"
    default y
    help
        Support for parsing X.509 Certifificate Revocation Lists.

config MBEDTLS_X509_CSR_PARSE_C
    bool "X.509 CSR parsing"
    default y
    help
        Support for parsing X.509 Certifificate Signing Requests

endmenu # Certificates

menuconfig MBEDTLS_ECP_C
    bool  "Elliptic Curve Ciphers"
    default y

config MBEDTLS_ECDH_C
    bool "Elliptic Curve Diffie-Hellman (ECDH)"
    depends on MBEDTLS_ECP_C
    default y
    help
        Enable ECDH. Needed to use ECDHE-xxx TLS ciphersuites.

config MBEDTLS_ECDSA_C
    bool "Elliptic Curve DSA"
    depends on MBEDTLS_ECDH_C
    default y
    help
        Enable ECDSA. Needed to use ECDSA-xxx TLS ciphersuites.

config MBEDTLS_ECP_DP_SECP192R1_ENABLED
    bool "Enable SECP192R1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        Enable support for SECP192R1 Elliptic Curve.

config MBEDTLS_ECP_DP_SECP224R1_ENABLED
    bool "Enable SECP224R1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        Enable support for SECP224R1 Elliptic Curve.

config MBEDTLS_ECP_DP_SECP256R1_ENABLED
    bool "Enable SECP256R1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        Enable support for SECP256R1 Elliptic Curve.

config MBEDTLS_ECP_DP_SECP384R1_ENABLED
    bool "Enable SECP384R1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        Enable support for SECP384R1 Elliptic Curve.

config MBEDTLS_ECP_DP_SECP521R1_ENABLED
    bool "Enable SECP521R1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        Enable support for SECP521R1 Elliptic Curve.

config MBEDTLS_ECP_DP_SECP192K1_ENABLED
    bool "Enable SECP192K1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        Enable support for SECP192K1 Elliptic Curve.

config MBEDTLS_ECP_DP_SECP224K1_ENABLED
    bool "Enable SECP224K1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        Enable support for SECP224K1 Elliptic Curve.

config MBEDTLS_ECP_DP_SECP256K1_ENABLED
    bool "Enable SECP256K1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        Enable support for SECP256K1 Elliptic Curve.

config MBEDTLS_ECP_DP_BP256R1_ENABLED
    bool "Enable BP256R1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        support for DP Elliptic Curve.

config MBEDTLS_ECP_DP_BP384R1_ENABLED
    bool "Enable BP384R1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        support for DP Elliptic Curve.

config MBEDTLS_ECP_DP_BP512R1_ENABLED
    bool "Enable BP512R1 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        support for DP Elliptic Curve.

config MBEDTLS_ECP_DP_CURVE25519_ENABLED
    bool "Enable CURVE25519 curve"
    depends on MBEDTLS_ECP_C
    default y
    help
        Enable support for CURVE25519 Elliptic Curve.

config MBEDTLS_ECP_NIST_OPTIM
    bool "NIST 'modulo p' optimisations"
    depends on MBEDTLS_ECP_C
    default y
    help
        NIST 'modulo p' optimisations increase Elliptic Curve operation performance.

        Disabling this option saves some code size.

# end of Elliptic Curve options

endmenu  # mbedTLS