diff --git a/poly1305.cpp b/poly1305.cpp
index e79cf386..0473dc5f 100644
--- a/poly1305.cpp
+++ b/poly1305.cpp
@@ -165,6 +165,7 @@ void Poly1305_Base<T>::HashBlocks(const byte *input, size_t length, word32 padbi
 template <class T>
 void Poly1305_Base<T>::TruncatedFinal(byte *mac, size_t size)
 {
+	CRYPTOPP_ASSERT(mac);      // Pointer is valid
 	CRYPTOPP_ASSERT(!m_used);  // Nonce is fresh
 
 	ThrowIfInvalidTruncatedSize(size);
diff --git a/siphash.h b/siphash.h
index aa6bc8fa..8194d4b8 100644
--- a/siphash.h
+++ b/siphash.h
@@ -203,6 +203,10 @@ void SipHash_Base<C,D,T_128bit>::Update(const byte *input, size_t length)
 template <unsigned int C, unsigned int D, bool T_128bit>
 void SipHash_Base<C,D,T_128bit>::TruncatedFinal(byte *digest, size_t digestSize)
 {
+	CRYPTOPP_ASSERT(digest);      // Pointer is valid
+
+	ThrowIfInvalidTruncatedSize(digestSize);
+
 	// The high octet holds length and is digested mod 256
 	m_b[0] += m_idx; m_b[0] <<= 56U;
 	switch (m_idx)