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Cryptology - Unofficial St. Mary's College of California Web Site

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230 CHAPTER 11. KNAPSACK CIPHERS<br />

9. A different way to hide the super-increasing nature <strong>of</strong> the weights would<br />

be to put the “superincreasingness” inside the numbers. For example<br />

W 1 = 2900104<br />

W 2 = 3200209<br />

W 3 = 5500401<br />

W 4 = 1300810<br />

W 5 = 2401604.<br />

(The boldness only serves to show where the super-increasing is hidden.)<br />

The modulus would be correspondingly large, say P = 200785471.<br />

(a) Use e = 41233 to find the corresponding U’s.<br />

(b) Encipher huge.<br />

(c) Which <strong>of</strong> the following may be written as a sum <strong>of</strong> the W ’s<br />

a) 36902109 b) 33501123 c) 10001420 d) 9705114 (Hint: only<br />

three digits really matter. Which three.<br />

(d) Decipher 195046101, 76263779, 175978897, 160072206.

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