Scroll to navigation

base32(3tcl) Base32 encoding base32(3tcl)


base32 - base32 standard encoding


package require Tcl 8.4

package require base32::core ?0.1?

package require base32 ?0.1?

::base32::encode string

::base32::decode estring


This package provides commands for encoding and decoding of strings into and out of the standard base32 encoding as specified in RFC 3548.


::base32::encode string
This command encodes the given string in base32 and returns the encoded string as its result. The result may be padded with the character = to signal a partial encoding at the end of the input string.
::base32::decode estring
This commands takes the estring and decodes it under the assumption that it is a valid base32 encoded string. The result of the decoding is returned as the result of the command.

Note that while the encoder will generate only uppercase characters this decoder accepts input in lowercase as well.

The command will always throw an error whenever encountering conditions which signal some type of bogus input, namely if

the input contains characters which are not valid output of a base32 encoder,
the length of the input is not a multiple of eight,
padding appears not at the end of input, but in the middle,
the padding has not of length six, four, three, or one characters,


The code map used to convert 5-bit sequences is shown below, with the numeric id of the bit sequences to the left and the character used to encode it to the right. It should be noted that the characters "0" and "1" are not used by the encoding. This is done as these characters can be easily confused with "O", "o" and "l" (L).

	0 A    9 J   18 S   27 3
	1 B   10 K   19 T   28 4
	2 C   11 L   20 U   29 5
	3 D   12 M   21 V   30 6
	4 E   13 N   22 W   31 7
	5 F   14 O   23 X
	6 G   15 P   24 Y
	7 H   16 Q   25 Z
	8 I   17 R   26 2


This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category base32 of the Tcllib Trackers []. Please also report any ideas for enhancements you may have for either package and/or documentation.

When proposing code changes, please provide unified diffs, i.e the output of diff -u.

Note further that attachments are strongly preferred over inlined patches. Attachments can be made by going to the Edit form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar.


base32, rfc3548


Text processing


Public domain
0.1 tcllib