Re: Encryption key longer than text to encrypt



Jean-François Michaud wrote:
Since it is easier in practice to use pseudo random data than to
generate random data which is then distributed as appropriate if we
have OTP in mind,

Forget about OTP. You are describing a stream cipher.

would
encrypting messages à la OTP with 'pseudo random data' using a key
greater than the message make any sense to increase security,

Yes and no - but mostly no.

No. A thing called the unicity distance will enable the attacker with good probability to tell that he has the right message.

Yes. The attacker has several places he may have to try and start.

Embassies and highly secure line do something a lot better they send true random data 24/7 and insert messages when ever they have to. This denies signal intelligence to any observer.


This process is akin to steganography except the message is known to be
encrypted amongst a sea of junk.

The it is not like stego.

When anyone tries to help you, you just hurl abuse. So I'm going back to bed after I snip the rest.

(snip)
.



Relevant Pages

  • Re: Encryption key longer than text to encrypt
    ... have OTP in mind, ... Forget about OTP. ... true random data 24/7 and insert messages when ever they have to. ... Thats an interresting idea. ...
    (sci.crypt)
  • Re: "Random flood" crypto
    ... I choose my attacker to be completely incompetent and doesn't even know how to turn on a computer, ROT-13 is perfectly secure, even ASCII offers superior security. ... If your download resources are finite then the attacker can simply parse it to what you can download and *poof* its breakable. ... There's a reason it isn't actually used, that reason is that it doesn't have any real advantage. ... actually most embassies transmit random data continuously and slip in encrypted data only when required. ...
    (sci.crypt)
  • Re: "Random flood" crypto
    ... David Eather wrote: ... choose limits for the attacker and I'll prove anything secure. ... conventional symmetric cipher. ... actually most embassies transmit random data continuously and slip ...
    (sci.crypt)
  • Re: encryption programs
    ... > he doesn't know where in the database they'll occur. ... > file to make it even harder for an attacker to guess where to find ... > expected plaintext - that wouldn't add much to the security, ... the random data to expect at the start of the database, ...
    (comp.os.linux.security)
  • Re: Testing whole disk encryption
    ... the attacker has to try at most a fairly small number of index ... fresh sample disk, initialize it, write random data to disk, make a copy ... of the entire raw disk, write new random data to disk, compare to the copy ... The vendor could prevent it easily by storing a pair of blocks, which xored together gives the the data. ...
    (sci.crypt)