diff --git a/cardano-crypto-class/src/Cardano/Crypto/Libsodium/Memory/Internal.hs b/cardano-crypto-class/src/Cardano/Crypto/Libsodium/Memory/Internal.hs
index 74c91cc94..7455bb5d5 100644
--- a/cardano-crypto-class/src/Cardano/Crypto/Libsodium/Memory/Internal.hs
+++ b/cardano-crypto-class/src/Cardano/Crypto/Libsodium/Memory/Internal.hs
@@ -118,7 +118,7 @@ makeMLockedPool = do
     )
 
 eraseMem :: forall n a. KnownNat n => Proxy n -> Ptr a -> IO ()
-eraseMem proxy ptr = fillBytes ptr 0xff (fromIntegral @Integer @Int $ natVal proxy)
+eraseMem proxy ptr = fillBytes ptr 0x00 (fromIntegral @Integer @Int $ natVal proxy)
 
 mlockedPool32 :: Pool 32 RealWorld
 mlockedPool32 = unsafePerformIO $ stToIO makeMLockedPool