Base32: Difference between revisions

Base 32 or duotrigesimal is a positional notation using a base of 32. The twenty-six letters A-Z and six digits 2-7 can be used to provide the 32 separate symbols needed.

Software

In computing terminology, Base32 (spelled without a space) is an alternative to Base64 as a notation for encoding arbitrary byte data using a restricted set of symbols which can be conveniently used by humans and processed by old computer systems which only recognize restricted character sets.

Advantages

Base32 has two main advantages over Base64:

1. The resulting character set is all one case (usually represented as uppercase), which can often be beneficial when using a case-insensitive filesystem, or human memory.
2. The result can be included in a URL without encoding any characters.

Base32 alphabet

It uses an alphabet of A–Z, followed by 2–7 (thus "2" actually has a numerical value of 26). 0 and 1 are skipped due to their similarity with the letters O and I.

The Base 32 alphabet

Value	Symbol	Value	Symbol	Value	Symbol	Value	Symbol
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	pad	=

Alternate versions

An earlier form of base 32 notation was used by programmers working on the Electrologica X1 to represent machine addresses. The "digits" were represented as decimal numbers from 0 to 31. For example, 12-16 would represent the machine address 400.

Another alternative design for Base32 is created by Douglas Crockford, who proposes using additional characters for a checksum.[1]

Alternate Base32 alphabet

Value	Encode Digit	Decode Digit	Value	Encode Digit	Decode Digit
0	0	O o 0	16	G	g G
1	1	I i L l 1	17	H	h H
2	2	2	18	J	j J
3	3	3	19	K	k K
4	4	4	20	M	m M
5	5	5	21	N	n N
6	6	6	22	P	p P
7	7	7	23	Q	q Q
8	8	8	24	R	r R
9	9	9	25	S	s S
10	A	a A	26	T	t T
11	B	b B	27	V	v V
12	C	c C	28	W	w W
13	D	d D	29	X	x X
14	E	e E	30	Y	y Y
15	F	f F	31	Z	z Z

Triacontakaidecimal is another alternative design for Base32, that extends Hexadecimal in a more natural way, steming from a 32 sided triacontakaidigon. Note the difference between 0, O and 1, I. They are similar, but still distinguishable in ansii.

Triacontakia	Binary	Decimal
0	00000000	0
1	00000001	1
2	00000010	2
3	00000011	3
4	00000100	4
5	00000101	5
6	00000110	6
7	00000111	7
8	00001000	8
9	00001001	9
A	00001010	10
B	00001011	11
C	00001100	12
D	00001101	13
E	00001110	14
F	00001111	15
G	00010000	16
H	00010001	17
I	00010010	18
J	00010011	19
K	00010100	20
L	00010101	21
M	00010110	22
N	00010111	23
O	00011000	24
P	00011001	25
Q	00011010	26
R	00011011	27
S	00011100	28
T	00011101	29
U	00011110	30
V	00011111	31

By Caleb Piercy.

Video games

Before NVRAM became universal, several video games for Nintendo platforms use base 32 numbers for passwords. These systems omit vowels to prevent the game from accidentally giving a profane password. Thus, the characters are generally some minor variation of the following set: 0-9, B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, W, X, Y, Z, and some punctuation mark. Games known to use such a system include Mario Is Missing!, Mario's Time Machine, Tetris Blast, and The Lord of the Rings (Super NES).

References

• RFC 4648

See also

• Base64