RE: How to generate account number?
Jose, absolutely, let me know should you have any issues. Andriy Date: Fri, 2 Nov 2012 15:29:13 -0600 Subject: Re: How to generate account number? From: josen.figue...@unixmexico.org To: andriy.kornats...@live.com CC: python-list@python.org Hello Andriy Thanks for your work! I will try it! Jose On Fri, Nov 2, 2012 at 3:13 PM, Andriy Kornatskyy andriy.kornats...@live.commailto:andriy.kornats...@live.com wrote: Requirements for `account number` generator: 1. Issue pseudo random consistent number (must be unique for dozen millions of records) 2. Easy check validity (without a need to make a database call) Interested? Read more here: http://mindref.blogspot.com/2012/11/generate-account-number.html Comments or suggestions are welcome. Thanks. Andriy Kornatskyy -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
RE: How to generate account number?
from hashlib import sha1
sha1('GangGreene-20120203-1012').hexdigest()
'ef764a2fe44532008dc9a99c391c70cd85ec9d82'
It is too long and not verifiable.
from uuid import uuid4
uuid4()
UUID('2c14484b-5a0c-4f4b-b7bc-8187548b4888')
Pretty much the same what you suggest but simpler and shorter. Not quite
elegant for humans.
Here are examples per this post:
http://mindref.blogspot.com/2012/11/generate-account-number.html
account_number(1)
'Z05738521581'
account_number(2)
'Z17888279480'
account_number(3)
'Z07395350007'
Short, human readable and satisfy original requirements.
Andriy
From: ganggre...@example.com
Subject: Re: How to generate account number?
Date: Fri, 2 Nov 2012 18:02:09 -0400
To: python-list@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)
2. Easy check validity (without a need to make a database call)
Interested? Read more here:
http://mindref.blogspot.com/2012/11/generate-account-number.html
Comments or suggestions are welcome.
Thanks.
Andriy Kornatskyy
generate sha1sum on the ((key database record(s))+date+timeofday)
Should be unique for billions/trillions of records.
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RE: How to generate account number?
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 + To: python-list@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. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to generate account number?
In article mailman.3234.1351931985.27098.python-l...@python.org, Andriy Kornatskyy andriy.kornats...@live.com wrote: 'Z05738521581' 'Z17888279480' 'Z07395350007' Short, human readable and satisfy original requirements. Andriy If you really want human readable, it's better to chunk the data up into 3 or 4 digit groups. So, instead of Z05738521581, maybe Z05-738-521-581. Or perhaps even better, Z05-7385-21-581 (just a hunch, but I suspect varying the length of the groups makes it easier to read). Even better might be base-32 encoding the value. Strings of digits have an information density of about 3.2 bits/char. Base-32 is just about as readable, but gives you 5 bits/char, so you end up with a few less characters (which you still want to chunk into 3 or 4 character groups). -- http://mail.python.org/mailman/listinfo/python-list
Re: How to generate account number?
On 11/02/2012 03:13 PM, Andriy Kornatskyy wrote: Requirements for `account number` generator: 1. Issue pseudo random consistent number (must be unique for dozen millions of records) 2. Easy check validity (without a need to make a database call) Interested? Read more here: http://mindref.blogspot.com/2012/11/generate-account-number.html Comments or suggestions are welcome. Thank you for sharing. Your post came along at just the right time. I was just pondering on how to create a number that is unique each time (or most of the time), and unlikely to be guessed ahead of time. Your technique should work very well for me. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to generate account number?
On 11/03/12 08:22, Roy Smith wrote:
Even better might be base-32 encoding the value. Strings of
digits have an information density of about 3.2 bits/char.
Base-32 is just about as readable, but gives you 5 bits/char, so
you end up with a few less characters (which you still want to
chunk into 3 or 4 character groups).
For things that will be read off a screen/paper, I recommend
omitting several letters that are easy to mistake visually: i/I/l/1
and O/0 in particular. The VIN (vehicle identification number) on
all US cars avoids these characters[*], making it easier to read
them back without concern for is that a zero or an oh; and is that
an ell, a one, a lowercase eye, or a capital eye? As an encoding
advantage,
print len(''.join(c for c in (string.ascii_uppercase +
string.digits) if c not in O0iIl1))
32
the number 32 is pretty handy when dealing with binary :-)
-tkc
[*]
The VIN avoids Q too and does use the digits 0/1, but the idea
holds. Make it easy to ready back.
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RE: How to generate account number?
Roy, Per your advise: from base64 import b32encode human_format = lambda n: 'Z%s-%s' % (b32encode(chr((n 24) 255) + chr((n 16) 255))[:4], b32encode(chr((n 8) 255) + chr(n 255))[:4]) human_format(5738521581) 'ZKYFA-4PWQ' human_format(17888279480) 'ZFI4Q-PO4A' human_format(7395350007) 'ZXDGA-CX3Q' Side by side: Z05738521581 = ZKYFA-4PWQ Z17888279480 = ZFI4Q-PO4A Z07395350007 = ZXDGA-CX3Q Thanks. Andriy From: r...@panix.com Subject: Re: How to generate account number? Date: Sat, 3 Nov 2012 09:22:55 -0400 To: python-list@python.org In article mailman.3234.1351931985.27098.python-l...@python.org, Andriy Kornatskyy andriy.kornats...@live.com wrote: 'Z05738521581' 'Z17888279480' 'Z07395350007' Short, human readable and satisfy original requirements. Andriy If you really want human readable, it's better to chunk the data up into 3 or 4 digit groups. So, instead of Z05738521581, maybe Z05-738-521-581. Or perhaps even better, Z05-7385-21-581 (just a hunch, but I suspect varying the length of the groups makes it easier to read). Even better might be base-32 encoding the value. Strings of digits have an information density of about 3.2 bits/char. Base-32 is just about as readable, but gives you 5 bits/char, so you end up with a few less characters (which you still want to chunk into 3 or 4 character groups). -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
RE: How to generate account number?
Tim,
Good point. b32decode seems to be capable to understand such common mistakes
(see map01 argument to b32decode), I haven't tried:
http://docs.python.org/2/library/base64.html
Thanks.
Andriy
Date: Sat, 3 Nov 2012 10:34:26 -0500
From: python.l...@tim.thechases.com
To: r...@panix.com
Subject: Re: How to generate account number?
CC: python-list@python.org
On 11/03/12 08:22, Roy Smith wrote:
Even better might be base-32 encoding the value. Strings of
digits have an information density of about 3.2 bits/char.
Base-32 is just about as readable, but gives you 5 bits/char, so
you end up with a few less characters (which you still want to
chunk into 3 or 4 character groups).
For things that will be read off a screen/paper, I recommend
omitting several letters that are easy to mistake visually: i/I/l/1
and O/0 in particular. The VIN (vehicle identification number) on
all US cars avoids these characters[*], making it easier to read
them back without concern for is that a zero or an oh; and is that
an ell, a one, a lowercase eye, or a capital eye? As an encoding
advantage,
print len(''.join(c for c in (string.ascii_uppercase +
string.digits) if c not in O0iIl1))
32
the number 32 is pretty handy when dealing with binary :-)
-tkc
[*]
The VIN avoids Q too and does use the digits 0/1, but the idea
holds. Make it easy to ready back.
--
http://mail.python.org/mailman/listinfo/python-list
--
http://mail.python.org/mailman/listinfo/python-list
Re: How to generate account number?
Hello Andriy Thanks for your work! I will try it! Jose On Fri, Nov 2, 2012 at 3:13 PM, Andriy Kornatskyy andriy.kornats...@live.com wrote: Requirements for `account number` generator: 1. Issue pseudo random consistent number (must be unique for dozen millions of records) 2. Easy check validity (without a need to make a database call) Interested? Read more here: http://mindref.blogspot.com/2012/11/generate-account-number.html Comments or suggestions are welcome. Thanks. Andriy Kornatskyy -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: How to generate account number?
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) 2. Easy check validity (without a need to make a database call) Interested? Read more here: http://mindref.blogspot.com/2012/11/generate-account-number.html Comments or suggestions are welcome. Thanks. Andriy Kornatskyy generate sha1sum on the ((key database record(s))+date+timeofday) Should be unique for billions/trillions of records. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to generate account number?
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. 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 Interested? Read more here: If you ask a question here, please keep the discussion here, don't split it to your personal blog. Tell us your requirements in more detail, and we will try to help you. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
