I have two files, one in plain-text and one encrypted. I don't know what kind of encryption is used. But based on my limited knowledge, I guess it is possible to compare them.
Now I have a third encrypted file; however, this one does not have a corresponding plain-text file. So I need to figure the encryption out between the first two files to unlock the third. I know the encryption used is the same as with the other one.
I have heard about a known plain-text attack, but how do you do it?
How can I do this? Are there any software for it?
Thank you. :)