diff --git a/include/psa/crypto_struct.h b/include/psa/crypto_struct.h
index d9e9b86..fdf78a8 100644
--- a/include/psa/crypto_struct.h
+++ b/include/psa/crypto_struct.h
@@ -250,8 +250,8 @@
 #endif
 
     /* Indicates how many bytes in the current HMAC block have
-     * already been read by the user. */
-    uint8_t offset_in_block;
+     * not yet been read by the user. */
+    uint8_t left_in_block;
 
     /* The 1-based number of the block. */
     uint8_t block_number;