Re: Electronic Codebook

s_4@wp.pl writes:
> Some criminal, who can modifity content of incrypted messages (banks'
> transfers), make a 17 transfers to his own bank account, allways on the
> same amount (sum). Then he searching in sending messages, such
> incrypted number of bank account, which were send exactly 17 times and
> on the same amount (sum). He recognize incrypted version of his no.
> bank account, despite he doesn't know the key. Why he have to make 17
> transfers?

The bank is using bad encryption if that attack is possible. With
good encryption, if you encrypt the word "hello" 17 times, you'll get
17 different results. The attacker can't tell that you've encrypted
the same word each time.
Received on Thu Jan 19 03:44:32 2006