Account Options

  1. Sign in
The old Google Groups will be going away soon, but your browser is incompatible with the new version.
Google Groups Home
« Groups Home
comp.lang.python
+ new post
About this group
Subscribe to this group
This is a Usenet group - learn more
Message from discussion How to generate account number?
The group you are posting to is a Usenet group. Messages posted to this group will make your email address visible to anyone on the Internet.
Your reply message has not been sent.
Your post was successful
 
From:
To:
Cc:
Followup To:
Add Cc | Add Followup-to | Edit Subject
Subject:
Validation:
For verification purposes please type the characters you see in the picture below or the numbers you hear by clicking the accessibility icon. Listen and type the numbers you hear
 
Andriy Kornatskyy  
View profile  
 More options Nov 3 2012, 4:43 am
Newsgroups: comp.lang.python
From: Andriy Kornatskyy <andriy.kornats...@live.com>
Date: Sat, 3 Nov 2012 11:42:38 +0300
Local: Sat, Nov 3 2012 4:42 am
Subject: RE: How to generate account number?
Print | View thread | Show original | Report this message | Find messages by this author

Steven, see below, please.

----------------------------------------

> From: steve+comp.lang.pyt...@pearwood.info
> Subject: Re: How to generate account number?
> Date: Fri, 2 Nov 2012 22:39:31 +0000
> To: python-l...@python.org

> On Sat, 03 Nov 2012 00:13:19 +0300, Andriy Kornatskyy wrote:

>> Requirements for `account number` generator:

>> 1. Issue pseudo random consistent number (must be unique for dozen
>> millions of records)

> How much randomness do you need? From the perspective of any one user, a
> simple incrementing counter returns arbitrary values, which may be "close
> enough" to random.

> last_num = 103872 # Pick an arbitrary starting value.
> def get_account_number():
> """Return the next account number."""
> global last_num
> last_num += 1
> return last_num

> Stick that value in a database instead of a global, and you're done.

> What are the consequences of people guessing account numbers? If the
> consequences are serious, then you need to make account numbers
> cryptographically strong. If the account number alone is not important,
> then you don't.

Yes. There are consequences to not use sequential numbers, yet humans deal with it (enter as input somewhere, etc). The approach suggested here:

http://mindref.blogspot.com/2012/11/generate-account-number.html

is using Feistel cipher to generate pseudo random thus makes guessing account numbers hard (impossible?).

>> 2. Easy check validity (without a need to make a database call)

> Add a check digit to the number you generate. There are all sorts of ways
> to do that. Here are two examples:

> http://code.activestate.com/recipes/577692
> http://code.activestate.com/recipes/577691

These tell me how to verify some code, but doesn't how to generate it. The approach suggested here:

http://mindref.blogspot.com/2012/11/generate-account-number.html

gives you ability to customize `sample_f` function to make it unique to your business case.

>> Interested? Read more here:

> If you ask a question here, please keep the discussion here, don't split
> it to your personal blog.

The question was rhetorical with my answer in the blog and discussion here to reach something.

> Tell us your requirements in more detail, and we will try to help you.

I have presented solution to `account number` challenge. So it was share with community and seek for thoughts if any.

 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Create a group - Google Groups - Google Home - Terms of Service - Privacy Policy
©2013 Google