Pure Python Data Mangling or Encrypting

[Jon Ribbens]

On 2015-06-26, Chris Angelico <rosuav at gmail.com> wrote:
> On Fri, Jun 26, 2015 at 1:26 AM, Jon Ribbens
><jon+usenet at unequivocal.co.uk> wrote:
>> Well, it means you need to send 256 times as much data, which is a
>> start. If you're instead using a 256-byte translation table then
>> an attack becomes utterly impractical.
>
> Utterly impractical? Maybe, if you attempt a pure brute-force approach
> - there are 256! possible translation tables, which is roughly e500
> attempts [1], and at roughly four a microsecond [2] that'd still take
> a ridiculously long time. But there are two gigantic optimizations you
> could do. Firstly, there are frequency-based attacks,

No, there aren't. As I already said, the attacker does not have the
ciphertext. He can't do anything related to frequency analysis.