Cryptography: RSA Message decryption

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SUMMARY

This discussion focuses on the RSA message decryption process, specifically converting the encoded message "BSSM" into a numerical format and then decrypting it using the RSA algorithm. The conversion process involves mapping letters to numbers, resulting in a temporary value of 30224. The decryption is performed using the formula temp^d mod n, yielding a result of 1371, which is then converted back to letters, revealing the original message "CAT". The correct decryption method and calculations are confirmed by the participants.

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ertagon2
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I've been trying to solve this question for quite a while now. I watched a ton of videos on RSA. But whenever I try to solve it I get weird answers. Can some pls give me a hint or their method of solving it. An answer to the question also would be fine.
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ertagon2 said:
I've been trying to solve this question for quite a while now. I watched a ton of videos on RSA. But whenever I try to solve it I get weird answers. Can some pls give me a hint or their method of solving it. An answer to the question also would be fine.

Hi ertagon2! Welcome to MHB!

What did you try?

Logically we would need to convert BSSM to a number using the same scheme as is used for encryption.
Then decode it with the given deciphering key.
And then convert the resulting number to a string again by taking the number modulus 26, dividing it by 26, and repeating.
 
I like Serena said:
Hi ertagon2! Welcome to MHB!

What did you try?

Logically we would need to convert BSSM to a number using the same scheme as is used for encryption.
Then decode it with the given deciphering key.
And then convert the resulting number to a string again by taking the number modulus 26, dividing it by 26, and repeating.

So i did convert BSSM to a number.
B= 1 S= 18 S= 18 M= 12, temp= 1*26^3 + 18*26^2 + 18*26^1 + 12*26^0 = 30224

According to the internet the deciphering process goes like this:
temp^d mod n = message

So
30224^26767 mod 46927 = 1371

And I can't convert 1371 to letters.I tried but I didn't get a good answer.
 
The answer is CAT
 
ertagon2 said:
So i did convert BSSM to a number.
B= 1 S= 18 S= 18 M= 12, temp= 1*26^3 + 18*26^2 + 18*26^1 + 12*26^0 = 30224

According to the internet the deciphering process goes like this:
temp^d mod n = message

So
30224^26767 mod 46927 = 1371

And I can't convert 1371 to letters.I tried but I didn't get a good answer.

ertagon2 said:
The answer is CAT

Let's see...

1371 mod 26 = 19, which corresponds to T.
1371 div 26 = 52, 52 mod 26 = 0, which corresponds to A.
52 div 26 = 2, which corresponds to C.

Yep. CAT.
 

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