Add ECJPAKE key exchange

include/mbedtls/check_config.h

@@ -192,6 +192,12 @@
 #error "MBEDTLS_KEY_EXCHANGE_RSA_ENABLED defined, but not all prerequisites"
 #endif
 
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) &&                    \
+    ( !defined(MBEDTLS_ECJPAKE_C) || !defined(MBEDTLS_SHA256_C) ||      \
+      !defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) )
+#error "MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED defined, but not all prerequisites"
+#endif
+
 #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C) &&                          \
     ( !defined(MBEDTLS_PLATFORM_C) || !defined(MBEDTLS_PLATFORM_MEMORY) )
 #error "MBEDTLS_MEMORY_BUFFER_ALLOC_C defined, but not all prerequisites"

include/mbedtls/config.h

@@ -694,6 +694,23 @@
  */
 #define MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED
 
+/**
+ * \def MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED
+ *
+ * Enable the ECJPAKE based ciphersuite modes in SSL / TLS.
+ *
+ * \warning Those are currently experimental.
+ *
+ * Requires: MBEDTLS_ECJPAKE_C
+ *           MBEDTLS_SHA256_C
+ *           MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ *
+ * This enables the following ciphersuites (if other requisites are
+ * enabled as well):
+ *      MBEDTLS_TLS_ECJPAKE_WITH_AES_128_CCM_8
+ */
+#define MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED
+
 /**
  * \def MBEDTLS_PK_PARSE_EC_EXTENDED
  *

include/mbedtls/ssl.h

@@ -389,6 +389,9 @@ union mbedtls_ssl_premaster_secret
     unsigned char _pms_ecdhe_psk[4 + MBEDTLS_ECP_MAX_BYTES
                                    + MBEDTLS_PSK_MAX_LEN];     /* RFC 5489 2 */
 #endif
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+    unsigned char _pms_ecjpake[32];     /* Thread spec: SHA-256 output */
+#endif
 };
 
 #define MBEDTLS_PREMASTER_SIZE     sizeof( union mbedtls_ssl_premaster_secret )

include/mbedtls/ssl_ciphersuites.h

@@ -244,6 +244,7 @@ typedef enum {
     MBEDTLS_KEY_EXCHANGE_ECDHE_PSK,
     MBEDTLS_KEY_EXCHANGE_ECDH_RSA,
     MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA,
+    MBEDTLS_KEY_EXCHANGE_ECJPAKE,
 } mbedtls_key_exchange_type_t;
 
 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)          || \