October 29th, 2012, 09:47 AM
Join Date: Oct 2012
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Crypto Algorithm Question - Block cipher - get the key?
these are the facts I know of the block cipher.
- the encryption function E
- the decryption function D
- x,y so that D(key,x) = D(key,y)+1
However, I don't know the key
But I have two datas (x,y
) which are the encrypted values
respectively its successor n+1
Assuming I knew the key, I could decrypt:
- D(key,x) = n+1
- D(key,y) = n
That is equivalent:
- E(key,n+1) = x
- E(key,n) = y
Remember I have x, y
If you have any idea, let me know.