[GnuPG-users] identical files -> non-identical encrypted files

[Kiss Gabor (Bitman)]

> > The password is not random therefore every time you
> > encrypt the same plaintext you got the same cryptfile.
> 
> No, you won't.  All sound encryption schemes use a bit of random to make
> the resulting ciphertext different.  In the easiest case this is called
> a salt and used to stop dictionary attacks.  For example, such a salt
> has been used for 25 years or so on all Unix systems to protect the
> login password.
> 
> > (The opposite would cause big problems in a disk encryption system. :-)
> 
> No.  Different ciphertexts may yield the same plaintext.

A test speaks for itself:

$ cat /etc/passwd | aespipe | md5sum
Password: 
9220c2e1d5a5a83710d020b04c306c24  -
$ cat /etc/passwd | aespipe | md5sum
Password: 
9220c2e1d5a5a83710d020b04c306c24  -
$ 

Cheers

Gabor