diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index b1c61c49..c237f9dd 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -23,6 +23,8 @@ jobs:
         CC: ["gcc", "clang" ]
     steps:
       - uses: actions/checkout@v3
+        with:
+          submodules: recursive
       - name: setup
         run: |
           sudo apt-get update && sudo apt-get install -y libcunit1-dev libtool libtool-bin exuberant-ctags valgrind
@@ -48,6 +50,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
+      with:
+        submodules: recursive
     - name: Build tinydtls
       run: |
         cmake -E make_directory build_test
@@ -60,6 +64,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
+      with:
+        submodules: recursive
     - name: Build tinydtls
       run: |
         cmake -E make_directory build_test
@@ -73,6 +79,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
+      with:
+        submodules: recursive
     - name: Build tinydtls
       run: |
         cmake -E make_directory build_test
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 551282f1..97701b19 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -70,11 +70,13 @@ target_sources(tinydtls PRIVATE
    aes/rijndael.c
    aes/rijndael_wrap.c
    sha2/sha2.c
-   ecc/ecc.c)
+   ext/micro-ecc/uECC.c)
 
-target_include_directories(tinydtls PUBLIC ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})
+target_include_directories(tinydtls PUBLIC ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/ext/micro-ecc )
 target_compile_definitions(tinydtls PUBLIC DTLSv12 WITH_SHA256 SHA2_USE_INTTYPES_H DTLS_CHECK_CONTENTTYPE)
 
+set_source_files_properties(ext/micro-ecc/uECC.c PROPERTIES COMPILE_OPTIONS "-Wno-pedantic;-Wno-unused-parameter;-Wno-missing-prototypes;-Wno-missing-declarations")
+
 if(CMAKE_GENERATOR MATCHES "Visual Studio")
     option(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS "Export all symbols when compiling to a .dll" ON)
     target_compile_options(tinydtls PRIVATE -Wall)
diff --git a/crypto.c b/crypto.c
index 1fe0807b..4a4ccc58 100644
--- a/crypto.c
+++ b/crypto.c
@@ -610,9 +610,10 @@ dtls_ecdsa_verify_sig_hash(const unsigned char *pub_key_x,
 			   unsigned char *result_r, unsigned char *result_s) {
   const dtls_ecdh_curve curve = default_curve;
   uint8_t pub_key[2 * DTLS_EC_KEY_SIZE];
+  assert(sizeof(pub_key) >= (key_size * 2));
   memcpy(pub_key, pub_key_x, key_size);
   memcpy(pub_key + key_size, pub_key_y, key_size);
-  return dtls_ecdsa_verify_sig_hash2(pub_key, key_size,
+  return dtls_ecdsa_verify_sig_hash2(pub_key, sizeof(pub_key),
                                      sign_hash, sign_hash_size,
                                      curve,
                                      result_r, result_s);
@@ -634,7 +635,6 @@ dtls_ecdsa_verify_sig_hash2(const unsigned char *pub_key, size_t key_size,
   (void)result_s;
 
   curve_size = uECC_curve_public_key_size(uecc_curve);
-
   assert(key_size == (unsigned int)curve_size);
   assert(sizeof(sign) >= (unsigned int)curve_size);