◄ WORLD V · SONNY 5DART 330 · a helldive at the net

THE HIDE mask a cell so it cannot be read — and can be perfectly unmasked

To hide a cell is to make its value unreadable without a key. The oldest perfect way is XOR with a key: 4 ⊕ 5 = 1. The masked cell reveals nothing about the original to anyone without the key — and yet the masking is perfectly reversible, because XOR is its own inverse: mask again with the same key and the original returns. This is the Vernam cipher, the mechanism of the one-time pad. Its mirror is dart 337, the reveal: hide and reveal are the same operation applied twice, so hide ∘ reveal = identity — the tightest palindrome in the batch, an op that is its own undo.

THE TECHNIQUE mask: cell ⊕ key (XOR); self-inverse, so reveal = the same op

The demo hides the core cell (value 4) under a key — the masked value tells you nothing: live demo







  
HISTORY & CREDIT the Vernam cipher / XOR mask · 1917

  
“To hide a value you must lock it away.” — XOR it with a key: unreadable to anyone without the key, and perfectly recoverable by anyone with it. The mask that is its own key. cited

  
1917–19 · Gilbert Vernam — the XOR stream cipher (the Vernam cipher); with a truly random key it is Shannon-perfect (the one-time pad).
self-inverse · x ⊕ k ⊕ k = x — encrypt and decrypt are the same operation.
mirror · dart 337, the reveal: the very same XOR, undoing the hide.

  
The core becomes 1 and gives nothing away; the key alone brings back the 4. To hide is to fold a cell under a mask that is its own undoing. Vernam, 1917






  
RECOMMEND FOR I-13 the masked cell, on the compiler

  
On the canonical compiler, hiding the core (4) under key 5 gives 1 — unreadable without the key:

  
$ i13 run d_hide.i13   # core ^ key
RUN OK · 8 step(s) · peak stack 2 · call depth 0
core = 4
key = 5
hidden = 1      -- masked; nothing recoverable without the key

  
Recommend, honestly not a keeper: the hide is the Vernam mask, and its beauty — that it is its own inverse — is exactly why it is not a new keeper: self-inverse is already the CRC/Verlet axis. What it contributes to the batch is the tightest palindrome pair: hide (dart 330) and reveal (dart 337) are one operation, so descending the nesting under a mask and ascending under the same mask returns every cell home. The self-inverse property the corpus already keeps, shown here as concealment.