[Cryptography] New White Paper: GhostLine - Information-Theoretically Secure Multi-Party Chat

[Patrick Chkoreff]

On 1/2/26 3:01 PM, Ray Dillinger wrote:

> The thing you missed is that knowing any one of the 256 bit blocks in 
> the OTP sequence is terrifyingly easy and can be done by passive 
> eavesdropping.

To recap, I had previously described a way to generate a pseudo-random 
OTP versus a truly-random OTP.

I was of course assuming that the OTP would never be reused, not even 
one block -- EVER.  That's the primary rule of using an OTP.  In that 
ideal perfect case, there cannot be a known-plaintext attack.

However, assuming that EVEN ONE block of the OTP is in fact reused, the 
difference between a pseudo-random OTP and a truly-random OTP is 
catastrophic.  In the pseudo-random case, you can recover that one block 
of key bits and, knowing the hash scheme, thereby reconstruct the entire 
remainder of the OTP.  That is not the case with a truly-random OTP, 
where each successive block is completely independent of the previous one.

So, the pseudo-random OTP is far more frail in the case of misuse, not 
so much because its randomness is measurably inferior by statistical 
tests, but because it is fundamentally deterministic.  That is something 
that a mere statistical test would not reveal, unless it was trained to 
look specifically for hash dependencies or other deterministic schemes.

Thanks Ray.


-- Patrick