#7123: cryptanalysis of the shift cipher
----------------------------+-----------------------------------------------
Reporter: mvngu | Owner: somebody
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.1.3
Component: cryptography | Keywords:
Work_issues: | Author: Minh Van Nguyen
Reviewer: | Merged:
----------------------------+-----------------------------------------------
Changes (by mvngu):
* status: needs_work => needs_review
Comment:
Replying to [comment:17 rbeezer]:
> 1. In the first paragraph of the doc string for
{{{characteristic_frequency()}}} you talk about plaintext and ciphertext.
Not sure somebody looking at this monoid code will be doing crypto. Could
you make the description more confined to properties of the monoid - just
describe it as a property of letters in English usage? The distinction
with the {{{frequency_distribution()}}} is very good, so retain that.
Done. The documentation for `characteristic_frequency()` has been re-
written to describe properties of a monoid. No more mentions of plaintext
or ciphertext. I have also made a slight coding change to that function to
increase its readability.
[[BR]][[BR]]
> 2. Does {{{frequency_distribution()}}} need documentation on its
inputs?
Done. I have documented the parameters of the method
`frequency_distribution()` and provided an example illustrating how to use
the key word "length".
[[BR]][[BR]]
> And should you change the nature of the output? Perhaps you should
stick to returning a probability space, and then just call
{{{function()}}} on it as needed to get the dictionary you want. Maybe
somebody else will want to get something different from the probability
distribution and want the more general object? In any event, the first
line of the docstring doesn't match the behavior.
Done. The method `frequency_distribution()` now returns a probability
space. In order to get the frequency probability distribution, use
`frequency_distribution().function()`.
[[BR]][[BR]]
> 3. Looked like there were some stray commented-out code statements in
the cryptanalysis code? Maybe you could review those and take out any
that might be misleading.
Fixed.
[[BR]][[BR]]
> 4. You probably don't need to give me credit for the chi-square and
squared-differences stuff, they are pretty standard measures of
differences. I also found the [SavHar99] reference more misleading than
helpful.
Fixed. I now only reference the Wikipedia articles on the Pearson chi-
square test, and the residual sum of squares measure.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7123#comment:19>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en
-~----------~----~----~----~------~----~------~--~---
