Re: One-Time Pad software?

[Atom Smasher <atom () smasher org>]

On Sat, 3 Feb 2007, FocusHacks wrote:

> Thanks for the information, guys.  As far as one-time pads being the 
> same length as the cleartext, I know how it works.  If a spy of days 
> past had a very long message to encrypt, he may need to use more than 
> one page of his paper pad.  By the same token, if I have a large binary 
> file to encrypt, but have stored several small files of random data to 
> use as my pad (and the receiving party has the same files and knows in 
> which order to utilize them), I would expect a tool to be able to handle 
> the task.  It's not convenient to generate a perfect-length pad file for 
> every ciphertext message I wish to transmit.  Looping a 20k file over a 
> larger cleartext message would not be OTP, it'd be a simple running key 
> algorithm that'd be a lot easier to break with simple heuristics. 
> Sure, it'd be a 20 kilobyte key, a lot less trivial than looping an 
> eight-letter lowercase word as a key, but it wouldn't be nearly as good 
> as a genuine OTP.
=====================================

a few CD-Rs can hold plenty of pad/key information. many paper shredders 
are advertised as being capable of shredding a CD... has anyone looked 
into the feasibility of putting a shredded CD back together?


> The reason I'm thinking small files is because on solid state media (for 
> instance, volatile storage in a PDA), it's easy to securely erase one 
> file at a time, which is much like burning the piece of paper you just 
> used.  correctly implemented, OTP is both computationally trivial to 
> perform, yet "perfectly secret", so long as the pad remains secure.
=====================================

it's actually *not* easy to erase one file at a time on PDAs, flash 
drives, etc. that discussion was about a week or so ago.


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