Hi Ron, I just love this KeyHolder thingy!  :)  Such a clever idea to resist a side-channel attack.  I'm curious how you came across the idea..

I did commit some improvements (see below), which I've tested, and plan to use in projects going forward.

As always, review and feedback is welcome from anyone and everyone.

Regards,
  Chris

________________________
Name: CryptographyCiphers-cmm.23
Author: cmm
Time: 15 September 2020, 5:52:41.154778 pm
UUID: 6ba3b5f5-47e3-48f7-a871-89a4cc4c0774
Ancestors: CryptographyCiphers-tpr.22

Improvements to KeyHolder:
- It can now hold an Integer or ByteArray key.
- Replaced use of KeyHolderData with a simple Array.  KeyHolderData removed.
- Destroys itself upon image save, to ensure not to save its contents in the image.
- More secure, now uses Rijndael (AES) instead of TripleDES.
- More secure, now destroys the prior encrypted key instead of waiting for GC.
- Now relies on a Mutex for process syncronization rather than trapping Error and retrying.
- Guards against invalid key access after it was destroyed.
- Better printOn: reveals its status.
- About 7X faster.