1 files changed, 2 insertions, 0 deletions
diff --git a/src/lib/mac/hmac/hmac.cpp b/src/lib/mac/hmac/hmac.cpp
index 32f62f0c2..244946d88 100644
--- a/src/lib/mac/hmac/hmac.cpp
+++ b/src/lib/mac/hmac/hmac.cpp
@@ -15,6 +15,7 @@ namespace Botan {
 */
 void HMAC::add_data(const uint8_t input[], size_t length)
    {
+   verify_key_set(m_ikey.empty() == false);
    m_hash->update(input, length);
    }
 
@@ -23,6 +24,7 @@ void HMAC::add_data(const uint8_t input[], size_t length)
 */
 void HMAC::final_result(uint8_t mac[])
    {
+   verify_key_set(m_okey.empty() == false);
    m_hash->final(mac);
    m_hash->update(m_okey);
    m_hash->update(mac, output_length());