Data Encoding Tutorials - Herong's Tutorial Examples - v5.23, by Herong Yang
Base32 Character Set Maps
This section describes some Base32 character set maps defined in RFC 3548 and RFC 2938.
RFC3548 Base32 Character Set Map
As described in the previous section, the most commonly used Base32 character set map is defined in RFC 3548 at https://tools.ietf.org/html/rfc4648:
Value Encoding Value Encoding Value Encoding Value Encoding
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
RFC2938 Base32 Character Set Map - base32hex
Another Base32 character set map is defined in RFC 2938 at http://tools.ietf.org/html/rfc2938, which is a natural extension of the hexadecimal character set map. Sometime this mapping is called base32hex or Extended Hex.
Value Encoding Value Encoding Value Encoding Value Encoding
0 0 9 9 18 I 27 R
1 1 10 A 19 J 28 S
2 2 11 B 20 K 29 T
3 3 12 C 21 L 30 U
4 4 13 D 22 M 31 V
5 5 14 E 23 N
6 6 15 F 24 O
7 7 16 G 25 P
8 8 17 H 26 Q
Crockford's Base32 Character Set Map - Modified base32hex
Douglas Crockford introduced a modified version of the Extended Hex map, at https://www.crockford.com/base32.html. He replaced 4 letters I L O and U with W X Y and Z to avoid confusion.
Value Encoding Value Encoding Value Encoding Value Encoding
0 0 9 9 18 J 27 V
1 1 10 A 19 K 28 W
2 2 11 B 20 M 29 X
3 3 12 C 21 N 30 Y
4 4 13 D 22 P 31 Z
5 5 14 E 23 Q
6 6 15 F 24 R
7 7 16 G 25 S
8 8 17 H 26 T
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