diff --git a/src/mesh/CryptoEngine.cpp b/src/mesh/CryptoEngine.cpp
index d296aa199..95c640d53 100644
--- a/src/mesh/CryptoEngine.cpp
+++ b/src/mesh/CryptoEngine.cpp
@@ -302,8 +302,8 @@ void CryptoEngine::hash(uint8_t *bytes, size_t numBytes)
 {
     SHA256 hash;
     size_t posn;
-    uint8_t size = numBytes;
-    uint8_t inc = 16;
+    size_t size = numBytes;
+    constexpr size_t inc = 16;
     hash.reset();
     for (posn = 0; posn < size; posn += inc) {
         size_t len = size - posn;
diff --git a/test/test_crypto/test_main.cpp b/test/test_crypto/test_main.cpp
index 7a93bdac4..448942ffe 100644
--- a/test/test_crypto/test_main.cpp
+++ b/test/test_crypto/test_main.cpp
@@ -47,6 +47,17 @@ void test_SHA256(void)
     crypto->hash(hash, 2);
     TEST_ASSERT_EQUAL_MEMORY(hash, expected, 32);
 }
+
+void test_SHA256_large_input(void)
+{
+    uint8_t hash[300] = {0};
+    uint8_t expected[32];
+
+    HexToBytes(expected, "d13d4a8b3b8add19b5970157f09d00c12cbda4fed4d74d8493156523f7069b66");
+    crypto->hash(hash, sizeof(hash));
+    TEST_ASSERT_EQUAL_MEMORY(hash, expected, sizeof(expected));
+}
+
 void test_ECB_AES256(void)
 {
     // https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Standards-and-Guidelines/documents/examples/AES_ECB.pdf
@@ -357,6 +368,7 @@ void setup()
     initializeTestEnvironment();
     UNITY_BEGIN(); // IMPORTANT LINE!
     RUN_TEST(test_SHA256);
+    RUN_TEST(test_SHA256_large_input);
     RUN_TEST(test_ECB_AES256);
     RUN_TEST(test_DH25519);
     RUN_TEST(test_AES_CTR);
@@ -371,4 +383,4 @@ void setup()
     exit(UNITY_END()); // stop unit testing
 }
 
-void loop() {}
\ No newline at end of file
+void loop() {}