# Math Help - RSA/cryptography question

1. ## RSA/cryptography question

I'm given a specific number (say n) to use "as an encryption key," and I have to find the decryption key.

Is n the same as the encryption exponent?

3. ## Re: RSA/cryptography question

So is the encryption key the same as the public key exponent e? The number I'm supposed to use as an encryption key is even, and it seems like it can't be the public key exponent because phi(m)=(p-1)(q-1) is also even.

4. ## Re: RSA/cryptography question

It sounds like you are given $m$, not $e$. So, you need to find $\varphi(m)$. Then the decryption key would be $e^{-1} \pmod{\varphi(m)}$? I dunno.

5. ## Re: RSA/cryptography question

Oh, just read through the link I sent you. It tells you precisely what to do in the section titled "A working example".

6. ## Re: RSA/cryptography question

Is there any way to use an even number as an encryption exponent?