diff --git a/Library/OcRngLib/OcRngLib.c b/Library/OcRngLib/OcRngLib.c
index 9144c10e..2e190ccf 100644
--- a/Library/OcRngLib/OcRngLib.c
+++ b/Library/OcRngLib/OcRngLib.c
@@ -96,7 +96,7 @@ ChaChaRngStir (
       mRng.Buffer[Index] ^= KeySeed[Index];
     }
     for (Index = 0; Index < ARRAY_SIZE (IvSeed); ++Index) {
-      mRng.Buffer[ARRAY_SIZE (KeySeed) + Index] ^= KeySeed[Index];
+      mRng.Buffer[ARRAY_SIZE (KeySeed) + Index] ^= IvSeed[Index];
     }
   } else {
     mRng.PrngInitialised = TRUE;