base32-crockford

A Python module implementing the alternate base32 encoding as described by Douglas Crockford at: http://www.crockford.com/wrmg/base32.html.

He designed the encoding to:

• Be human and machine readable
• Be compact
• Be error resistant
• Be pronounceable

It uses a symbol set of 10 digits and 22 letters, excluding I, L O and U. Decoding is not case sensitive, and 'i' and 'l' are converted to '1' and 'o' is converted to '0'. Encoding uses only upper-case characters.

Hyphens may be present in symbol strings to improve readability, and are removed when decoding.

A check symbol can be appended to a symbol string to detect errors within the string.

Installation

To install, simply run::

pip install base32-crockford

Usage

Basic usage example::

import base32_crockford base32_crockford.encode(42) '1A' base32_crockford.decode('1A') 42 base32_crockford.encode(42, checksum=True) '1A5' base32_crockford.decode('1A5', checksum=True) 42 base32_crockford.normalize('La5') '1A5'

Encode

::

   base32_crockford.encode(n[, checksum=False[, split=0]])

Encode an integer into a symbol string.

When ``True``, optional ``checksum`` causes a check symbol to be
calculated and appended to the string. This can help detect errors
when decoding.

When specified, optional ``split`` causes the output string to be
divided into clusters of that size separated by hyphens.

Decode

::

base32_crockford.decode(s[, checksum=False[, strict=False]])

Decode an encoded symbol string.

Optional checksum can be provided as a counterpart to the same argument when encoding. When True, the trailing check symbol is stripped off and validated. If the check symbol validation fails, a ValueError is raised.

When True, optional strict causes a ValueError to be raised if the symbol string requires normalization.

Normalize

::

   base32_crockford.normalize(s[, strict=False])

Normalize an encoded symbol string by applying these transformations:

   #. Remove hyphens
   #. Replace 'I' and 'L' with '1'
   #. Replace 'O' with '0'
   #. Convert all characters to uppercase

Ordinarily this function is automatically used when decoding, but
can be utilized independently to clean or validate a symbol string.
Invalid characters within the normalized string causes a
``ValueError`` to be raised.

When ``True``, optional ``strict`` causes a ``ValueError`` to be
raised if the symbol string requires normalization.

Changelog
---------

Version 0.3.0

   * Add Python 2.6 support
   * Add Python 3.3 and 3.4 support

Version 0.2.0

   * Add optional split parameter when encoding

Version 0.1.0

   * Initial release