Problem 44959. RSA encryption using public key

Created by David Hill
Appears in Advanced Cryptography Algorithms and Mathematics

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Encrypt the message text by converting to uint8 matrix using UTF-8 representation. Convert uint8 matrix to a large integer string. Use RSA encryption on the integer string given the public keys (n and e) and output the encrypted integer string. The public key (e) will always be fixed at 65537. No hashing or padding of the message is done.

For example:

message = 'I like to swim!';%given as input
integer_String = '379695297047669462525290688599911713';%calculated
n='418336393847020647250825879743341651032293545176800777981294580200903315345456262337972725306797613061';%given as input
e= 65537;%fixed
output_String = '158037161019988039882393476857386648994978438821991287680442802412825849535544067751541256843540494019';%output

See: https://simple.wikipedia.org/wiki/RSA_algorithm

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Solution Stats

47 Solutions
6 Solvers

Last Solution submitted on Mar 18, 2025

Last 200 Solutions

Problem Comments

3 Comments

3 Comments

William on 3 Sep 2019

Sorry, but I don't understand your instruction to "convert the uint8 array to a long integer string". Could you be more specific?

David Hill on 3 Sep 2019

Convert byte array into an integer/biginteger

Rafael S.T. Vieira on 23 Oct 2020

A better answer to William (and for people that don't use Java) would be that after converting numbers to uint8, we must transform a vector into a single number using base 256. That means that a word like 'ball' becomes [98, 97, 108, 108] and then 98*256^3 + 97*256^2 + 108*256 + 108 = 1650551916.