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Cryptography/Python: Derive the secret using Quadratic Residue knowledge

$30-250 SGD

Terminado
Publicado hace más de 6 años

$30-250 SGD

Pagado a la entrega
This is straightforward assignment to derive secret using Quadratic Residue knowledge. Formula: c = (s ^ r) mod p - s is the secret (an integer) to be encrypted using above formula - r is a random 500-bit number - p is a random 500-bit prime number - c is the ciphertext computed using this formula Above design is vulnerable, because attacker can calculate the value of s if he/she got enough pairs of <c, p> values. There are 3 tasks: Part 1: Later, I will provide a text file of 30 groups of <c, p> values. We only know s is an integer in the interval of [2410, 2459], but do not know which value is it. The mission is to write a Python program to derive the value of s, using those 30 groups of <c, p> values as inputs. Remarks: 1. Hint: you MUST use the knowledge of Quadratic residue. I can provide some reference to explain Quadratic residue if you need. 2. I can provide a short and simple Python code that how c, r, and p are generated. 3. This is not a brute force mission. You cannot simply compute the values from 2410 to 2459 and compare the outputs. 4. After last, write a concise and clear summary of algorithm at comment or in a separate file. Part 2: In part 1, the 30 random r’s were chosen so that s can be identified. Actually, if the 30 r’s are chosen uniformly and randomly, then there is a chance that we cannot uniquely identify s using 30 tuples. The probability of successful identification increases with large number of <c, p> tuples. Based on part 1, the mission is to give the least number of tuples required in order to achieve 99% of success, and explain it. You can write down the answer analytically without writing a new code. Part 3: Same as part 2, but the interval size of s increases into 10^6. The mission is still to write down the answer analytically.
ID del proyecto: 15512205

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6 propuestas
Proyecto remoto
Activo hace 6 años

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Hello, I'm software developer with 6+ years of experience in c++ and python, 10+ years in computer science. Also I'm participant and problem writer of many algorithm competitions (Topcoder, ACM ICPC) Relevant Skills and Experience c++ programming, python programming, math, algebra, cryptography Proposed Milestones $77 SGD - Let's create list of milestones later according our common vision of things that should be done If you have any docs/papers that might be helpful please share them with me.
$77 SGD en 2 días
4,8 (18 comentarios)
4,4
4,4
6 freelancers están ofertando un promedio de $120 SGD por este trabajo
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Hello, I have good experience in cryptography. so i am sure that i can do this project Relevant Skills and Experience c programming, C++, Python Proposed Milestones $250 SGD - all
$250 SGD en 3 días
4,9 (328 comentarios)
7,1
7,1
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A proposal has not yet been provided
$61 SGD en 1 día
4,8 (5 comentarios)
2,5
2,5
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Java, C/C++, Linux, PHP, MySQL, AJAX, JavaScript, C#, Visual Basic, PHP, MS SQL, My SQL, PHOTOSHOP, CSS, Bootstrap, HTML, JQUERY, JAVA, SCRIPT. Relevant Skills and Experience Java, C/C++, Linux, PHP, MySQL, AJAX, JavaScript, C#, Visual Basic, PHP, MS SQL, My SQL, PHOTOSHOP, CSS, Bootstrap, HTML, JQUERY, JAVA, SCRIPT. Proposed Milestones $100 SGD - milestones
$100 SGD en 3 días
0,0 (1 comentario)
0,0
0,0

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Bandera de SINGAPORE
Singapore, Singapore
4,9
7
Forma de pago verificada
Miembro desde nov 13, 2014

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