diff --git a/keccak.h b/keccak.h
index 5fd9b6b4..e8cabed3 100644
--- a/keccak.h
+++ b/keccak.h
@@ -83,7 +83,7 @@ public:
 	unsigned int BlockSize() const { return BLOCKSIZE; }
 private:
 	CRYPTOPP_COMPILE_ASSERT(BLOCKSIZE < 200); // ensure there was no underflow in the math
-	CRYPTOPP_COMPILE_ASSERT(BLOCKSIZE > T_DigestSize); // this is a general expectation by HMAC
+	CRYPTOPP_COMPILE_ASSERT(BLOCKSIZE > (int)T_DigestSize); // this is a general expectation by HMAC
 };
 
 //! \class Keccak_224
diff --git a/sha3.h b/sha3.h
index 23a18fad..e863b327 100644
--- a/sha3.h
+++ b/sha3.h
@@ -68,7 +68,7 @@ public:
 	unsigned int BlockSize() const { return BLOCKSIZE; }
 private:
 	CRYPTOPP_COMPILE_ASSERT(BLOCKSIZE < 200); // ensure there was no underflow in the math
-	CRYPTOPP_COMPILE_ASSERT(BLOCKSIZE > T_DigestSize); // this is a general expectation by HMAC
+	CRYPTOPP_COMPILE_ASSERT(BLOCKSIZE > (int)T_DigestSize); // this is a general expectation by HMAC
 };
 
 //! \class SHA3_224