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1. The House of Lilliput is using RSA encryption to receive secret messages from all the realms. They have published their public encoding exponent e=37 and their public modulus M = pq = 527.
Break the code: Find their secret decoding exponent d.

 

2. Find an integer x such that \(0 \leq x < 527\) and \(x^{37} \equiv 3 \pmod{527}\).

 

3. Let s be the set of numbers of the form n(n + 1)(n + 2)(n + 3)(n + 4), where n is any positive integer. The first few terms of s are \(1 \cdot 2 \cdot 3 \cdot 4 \cdot 5 = 120, 2 \cdot 3 \cdot 4 \cdot 5 \cdot 6 = 720, 3 \cdot 4 \cdot 5 \cdot 6 \cdot 7 = 2520,\)and so on. What is the GCD of the elements of s?

 Sep 3, 2016

Best Answer 

 #3
avatar+9519 
+7

1)\(n^{37}\equiv c\pmod {527}\)

   We first find the factors of 527

   527 = 17 x 31 according to this calc.

   We get an equation: \(37d = 1 \pmod{480}\)

   The smallest d that satisfies this equation is 37 x 13 = 1 (mod 480)

   Note: 37 x 13 = 481

   d = 13 ;D

2) x = 148 Same answer as Guest #1

3) 1 x 2 x 3 x 4 x 5 = 2^3 x 3 x 5

    2 x 3 x 4 x 5 x 6 = 2^4 x 3^2 x 5

    3 x 4 x 5 x 6 x 7 = 2^3 x 3^2 x 5 x 7  

They both have a common factor of 2^3 x 3 x 5 = 120.

 Sep 3, 2016
 #1
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+5

1) Read the article here about RSA system and how to encrypt and decrypt messages:

https://en.wikipedia.org/wiki/RSA_(cryptosystem)

 

2)    x=148

 Sep 3, 2016
 #2
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0

Also, watch this video by Dr. James Grime explaining how to encrypt and decrypt messages using RSA system: https://www.youtube.com/watch?v=M7kEpw1tn50

 Sep 3, 2016
 #3
avatar+9519 
+7
Best Answer

1)\(n^{37}\equiv c\pmod {527}\)

   We first find the factors of 527

   527 = 17 x 31 according to this calc.

   We get an equation: \(37d = 1 \pmod{480}\)

   The smallest d that satisfies this equation is 37 x 13 = 1 (mod 480)

   Note: 37 x 13 = 481

   d = 13 ;D

2) x = 148 Same answer as Guest #1

3) 1 x 2 x 3 x 4 x 5 = 2^3 x 3 x 5

    2 x 3 x 4 x 5 x 6 = 2^4 x 3^2 x 5

    3 x 4 x 5 x 6 x 7 = 2^3 x 3^2 x 5 x 7  

They both have a common factor of 2^3 x 3 x 5 = 120.

MaxWong Sep 3, 2016

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