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│        Encipher or Decipher a string of text.      │
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This  routine  requires that you supply two strings of
characters. The first is the text to be encrypted, and
the  second  is one or more keywords which are used to
encipher  the  text.  Thereafter,  the  text cannot be
decrypted until you supply the same key string again.

The  encryption algorithm XORs (eXclusive ORs) the key
string with string to be encrypted. This allows you to
reverse  the procedure and decrypt the text, simply by
calling the routine a second time.