base56

Human-readable binary encoding base56.

Base56 is a variant of Base58 encoding which further sheds the '1' and the lowercase 'o' characters in order to minimise the risk of fraud and human-error.

Base58 is similar to Base64, but modified to avoid both non-alphanumeric characters (+ and /) and letters that might look ambiguous when printed (0 – zero, I – capital i, O – capital o and l – lower-case L). Base58 is used to represent bitcoin addresses.[citation needed] Some messaging and social media systems break lines on non-alphanumeric strings. This is avoided by not using URI reserved characters such as +.

See also:

• Binary-to-text_encoding
• jyn514/base56
• baseconv
• Go package
• PHP Base56 encoding

Technical details

base56 translates the binary values from 0-55 to their counterpart in the following alphabet: 23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnpqrstuvwxyz

Usage

>>> from base56 import b56encode, b56decode
>>> b56encode(b"Hello World!")
'JjTDmGcemeMrgbs73'
>>> b56decode('JjTDmGcemeMrgbs73')
b'Hello World!'

Compatibility

We have different alphabets defined because the Go package and other packages use different alphabets.

>>> from base56 import PY3, GO_STD, GO_ALT, DEFAULT
>>> DEFAULT == PY3
True
>>> DEFAULT
Alphabet(b'23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnpqrstuvwxyz')
>>> DEFAULT.b56encode(b"Hello World!") # same as above
'JjTDmGcemeMrgbs73'
>>> GO_STD.b56decode(GO_STD.b56encode(b"Hello World!")) # from the Go implementation
b'Hello World!'
>>> GO_ALT.b56decode(GO_ALT.b56encode(b"Hello World!")) # from the PHP/Java implementation
b'Hello World!'

Skipping Characters

Characters that are not in the set can be skipped. By default, space characters are skipped.

>>> b56decode('JjTDm    GcemeMrgbs73\n')
b'Hello World!'
>>> b56decode('JjTDm    GcemeMrgbs73\n', skip=" \n")
b'Hello World!'

Ambiguity

If characters are ambiguous, they will be treated as the same characters. This only happens if they are included in the alphabet.

>>> GO_STD.decode("o2")  # lowercase letter o
b'p'
>>> GO_STD.decode("02")  # zero
b'p'
>>> GO_STD.decode("O2")  # capital letter o
b'p'
>>> GO_STD.decode("12")  # one
b'q'
>>> GO_STD.decode("I2")  # capital letter i
b'q'

Development

This project is created with tests. To run them, install tox.

tox

To create a new release, push a new tag.

git tag v0.1.0
git push origin v0.1.0

Changelog

• v0.1.1: Add ambiguity support for decoding
• v0.1.0: Initial release: Alphabets, encode, decode