Cryptography: RSA Message decryption

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In summary, After trying to solve a question for a while and watching several videos on RSA, the individual is unable to get the correct answer and requests a hint or method for solving it. Another individual provides a suggestion to convert the given string to a number and use a deciphering key to decode it. The individual follows the steps and gets the number 1371, but is unable to convert it to letters. After some assistance, the individual is able to successfully convert the number to the correct answer - CAT.
  • #1
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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  • #2
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.
 
  • #3
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.
 
  • #4
The answer is CAT
 
  • #5
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.
 

1. How does RSA message decryption work?

RSA message decryption works by using a public and private key pair. The public key is used to encrypt the message, while the private key is used to decrypt it. The sender uses the receiver's public key to encrypt the message, and the receiver uses their private key to decrypt it.

2. What is the purpose of RSA message decryption?

The purpose of RSA message decryption is to ensure secure communication between two parties. By using encryption and decryption techniques, sensitive information can be transmitted without the fear of interception or tampering by unauthorized individuals.

3. Can anyone decrypt a message encrypted with RSA?

No, only the intended recipient with the corresponding private key can decrypt a message encrypted with RSA. The private key is kept secret and should only be known by the recipient, making it difficult for anyone else to decrypt the message.

4. What are the limitations of RSA message decryption?

One limitation of RSA message decryption is that it can be computationally intensive, especially for large messages. This can result in slower communication speeds. Additionally, if the private key is compromised, the security of the system is compromised as well.

5. How does RSA ensure the security of the message?

RSA ensures the security of the message through the use of large prime numbers and mathematical operations that are difficult to reverse. These operations make it difficult for hackers to decrypt the message without the private key. Additionally, the use of a public and private key pair adds an extra layer of security to the system.

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