# RSA Decryption

Discussion in 'Computer Security' started by Thorben Grosser, Nov 18, 2004.

1. ### Thorben GrosserGuest

Hy folks,

I have been posed a question, and as i didn't get much out of google, I
am asking you wheather you would help me to solve this problem:

Nathaly wants to communicate to Daniel an important number, as well as
she decides to encrypt this number using the RSA Encyption. She sends
her the "message" (crypted): 7108707851160700458
Daniels Public key is:
- module N = 17401143680338538557
- exponent e = 65537
Surely, those numbers are too small to be confident. Findthe private
exponent of daniel and the number crypted by Nathaly.

can anyone help me out of this mess?

so long
Thorben

Thorben Grosser, Nov 18, 2004

2. ### MxsmanicGuest

Thorben Grosser writes:

> Hy folks,
>
> I have been posed a question, and as i didn't get much out of google, I
> am asking you wheather you would help me to solve this problem:
>
> Nathaly wants to communicate to Daniel an important number, as well as
> she decides to encrypt this number using the RSA Encyption. She sends
> her the "message" (crypted): 7108707851160700458
> Daniels Public key is:
> - module N = 17401143680338538557
> - exponent e = 65537
> Surely, those numbers are too small to be confident. Findthe private
> exponent of daniel and the number crypted by Nathaly.
>
> can anyone help me out of this mess?

If d = the decryption exponent, then

1. Factor N into p and q.
2. Knowing that de = 1 mod ((p-1)(q-1)), solve for d.

The modulus in this case is quite small, so you should be able to factor
it without too much trouble.

--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.

Mxsmanic, Nov 19, 2004

3. ### yer mammyGuest

plaintext: 864258521679854265

Thorben Grosser wrote:
> Hy folks,
>
> I have been posed a question, and as i didn't get much out of google, I
> am asking you wheather you would help me to solve this problem:
>
> Nathaly wants to communicate to Daniel an important number, as well as
> she decides to encrypt this number using the RSA Encyption. She sends
> her the "message" (crypted): 7108707851160700458
> Daniels Public key is:
> - module N = 17401143680338538557
> - exponent e = 65537
> Surely, those numbers are too small to be confident. Findthe private
> exponent of daniel and the number crypted by Nathaly.
>
> can anyone help me out of this mess?
>
> lloooots of thanks in advance
> so long
> Thorben

yer mammy, Nov 19, 2004