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, http://www.faqs.org/rfcs/rfc3548.html:

   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, 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, http://www.crockford.com/wrmg/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

Table of Contents

 About This Book

 UUEncode Encoding

 Base64 Encoding

Base32 Encoding

 Base32 Encoding Algorithm

Base32 Character Set Maps

 Bitpedia Implementation of Base32 in Java

 Bitpedia Implementation of Base32 in Java - Test

 Andre's Implementation of Base32 in PHP

 Andre's Implementation of Base32 in PHP - Test

 madebits Implementation of Base32 in C++

 URL Encoding, URI Encoding, or Percent Encoding

 References

 PDF Printing Version