Add Cryptoauthlib crypto BSP implementation (#25)

Added ATECC608 Secure Element reference implementation for generating JWT signatures with private keys.  See `src/bsp/crypto/cryptoauthlib/iotc_bsp_crypto_cryptoauthlib.c` for more information.

Author: fredrec

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "third_party/googletest"]
 	path = third_party/googletest
 	url = https://github.com/google/googletest
+[submodule "third_party/cryptoauthlib"]
+	path = third_party/cryptoauthlib
+	url = https://github.com/MicrochipTech/cryptoauthlib.git

.travis.yml

@@ -30,9 +30,11 @@ env:
       # WOLFSSL Tests
     - PRESET=POSIX_DEV
       IOTC_BSP_TLS=wolfssl
+      IOTC_BSP_CRYPTO=wolfssl
 
     - PRESET=POSIX_REL
       IOTC_BSP_TLS=wolfssl
+      IOTC_BSP_CRYPTO=wolfssl
 
     - PRESET=POSIX_THREADING_REL
     # - PRESET=POSIX_UNSECURE_REL

Makefile

@@ -32,6 +32,9 @@ MD ?= @
 # TLS related configuration
 IOTC_BSP_TLS ?= mbedtls
 
+# Cryptographic BSP implementation
+IOTC_BSP_CRYPTO ?= mbedtls
+
 #detect if the build happen on Travis
 ifdef TRAVIS_OS_NAME
 IOTC_TRAVIS_BUILD=1
@@ -133,7 +136,7 @@ clean_all: clean
 
 libiotc: $(XI)
 
-$(XI): $(IOTC_TLS_LIB_DEP) $(IOTC_PROTOFILES_C) $(IOTC_OBJS) $(IOTC_BUILD_PRECONDITIONS) | $(IOTC_BIN_DIRS)
+$(XI): $(IOTC_TLS_LIB_DEP) $(IOTC_CRYPTO_LIB_DEP) $(IOTC_PROTOFILES_C) $(IOTC_OBJS) $(IOTC_BUILD_PRECONDITIONS) | $(IOTC_BIN_DIRS)
 	$(info [$(AR)] $@ )
 	$(MD) $(AR) $(IOTC_ARFLAGS) $(IOTC_OBJS) $(IOTC_EXTRA_ARFLAGS)
 

README.md

@@ -90,7 +90,8 @@ Follow the steps below to perform the cross-compilation process.
 
 - Extend the build system with a new cross-compilation preset in the file `make/mt-config/mt-presets.mk`.
 - Create a set of files that represent the Board Support Package (BSP) implementation you've written for your platform. Store these in the directory `src/bsp/platform/TARGET_PLATFORM`.
-- Build a TLS library for the target platform in the directory `src/bsp/tls/TARGET_TLS_SOLUTION`.
+- Build a TLS BSP implementation to invoke the TLS SDK for your platform. Store these in a new directory `src/bsp/tls/TARGET_TLS_SOLUTION`.
+- Build a Cryptography BSP implementation to handle key signatures of JWTs on your target platform in the directory `src/bsp/crypto/TARGET_CRYPTO_SOLUCTION`.
 
 For more details on the cross-compilation process, see the porting guide in `doc/porting_guide.md`.
 

RELEASE-NOTES.md

@@ -5,6 +5,8 @@
 
 - Added Zephyr example.  See `examples/zephyr_native_posix/README.md` for more information.
 
+- Added ATECC608 Secure Element reference implementation for generating JWT signatures with private keys.  See `src/bsp/crypto/cryptoauthlib/iotc_bsp_crypto_cryptoauthlib.c` for more information.
+
 - Connection API Changes:
   - JWT creation and formation was added to a new header file `include/iotc_jwt.h`.
   - `iotc_connect` and `iotc_connect_to` now take the standard MQTT connect credentials of username, password, and client_id.  A JWT, formatted according to [Cloud IoT Core specifications](https://cloud.google.com/iot/docs/how-tos/credentials/jwts), should be passed as the MQTT password when connecting to Cloud IoT Core.