Guess My Word part 2

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Guess My Word part 2

• Add extra privacy to our communications! how
  is it done?

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Code Table

• Code Table
• Translate between English and numbers.

GOOD ? 7, 15, 15, 4
13, 1, 20, 8 ? Math
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-6, 16, -10, 36
Use matrix A to solve the word
8, 1, 18, 4
? HARD
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-8, 36, -4, 44, 41 10
? REVIEW
1, 2, 3, 4
?, ?, ?, ? Matrix A works like a key.
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How is it done?
Math is working behind the scene!
If
than
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• Pick a 4 to 6 letter word. 3 21 20 5
• Pick a simple 2x2 matrix call it matrix S for
  secret. (Make sure your matrix S is invertible!)

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• Multiply matrix S to your original word, two
  letters at a time. (Note If your word has odd
  number of letters, add a space in the end to make
  it even.)

• Put the result above in sequence into a new 1xN
  matrix matrix E for Encrypted. My E-45 -18
  -30 5
• Calculate the inverse matrix of S the inverse
  of S is matrix K for Key.

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• Now give the encoded sequence E and your key
  matrix K to others and see whether they can
  figure out what your original word is!