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Base-32 Crockford

Tool to decode / encode with the Crockford Base-32. Crockford's Base32 is a variant of base 32 created by Douglas Crockford improving use by humans.

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Base-32 Crockford -

Tag(s) : Character Encoding

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# Base-32 Crockford

## Crockford Base-32 Decoder

 Results format ASCII (printable) characters Hexadecimal 00-7F-FF Decimal 0-127-255 Octal 000-177-377 Binary 00000000-11111111 Integer number File to download

## Crockford base-32 Encoder

### What is the Crockford Base-32? (Definition)

The base-32 designed by Douglas Crockford is a variant of the base 32 (standard RFC 3548) willing to optimize the writing and reading by human and adding a sum of control. The Crockford base-32 uses 32 characters' 0123456789ABCDEFGHJKMNPQRSTVWXYZ 'ie the 36 alphanumeric characters excluding I,L,O to prevent confusion with digits and the letter' U 'which avoids unwanted puns (U=You).

Crockford optionally offers a modulo 37 checksum with 5 other characters: *~\$=U

### How to encrypt using Crockford Base-32 cipher?

The plain message is treated as a binary string and divided into 5-bit blocks (completed if necessary by 0).

Example: base is encoded in ASCII (8-bit) 01100010 01100001 01110011 01100101, the cutout gives the blocks 01100,01001,10000,10111,00110,11001,01000 (with three 0 added at the end)

Each block of 5 bits is encoded via the Crockford alphabet by its corresponding character:

00000 00001 00010 00011 0 1 2 3 4 5 6 7 8 9 A B C D E F G H J K M N P Q R S T V W X Y Z

Example: The coded message is C9GQ6S8

### How to calculate the checksum character?

The original binary message is encoded as a (very large) integer whose modulo value 37 is calculated (37 is the smallest next prime number following 32).

Example: base encoded in binary 01100010011000010111001101100101 (base 2) corresponds to 1650553701 (in decimal) and 1650553701 mod 37 = 18 which is coded 18=J so the control character is' J'

Example: The message coded with the control character is C9GQ6S8J

### How to decrypt using Crockford Base-32?

Crockford base-32 decryption starts with a conversion of characters into binary form via the lookup table

 0 1 2 3 00000 00001 00010 00011 00100 00101 00110 00111 01000 01001 01010 01011 01100 01101 01110 01111 10000 10001 10010 10011 10100 10101 10110 10111 11000 11001 11010 11011 11100 11101 11110 11111

Example: The message 6CS0 corresponds to 00110,01100,11001,00000

The resulting binary string is then interpreted (depending on the encoding or format used)

Example: 00110011,00110010,0000 is the ASCII code of the string 32

### How to recognize Crockford Base-32 ciphertext?

The message is composed of uppercase alphanumeric characters except I, L, O. It is also possible to find the characters *~\$=U at the end of the coding data and sometimes the dash/hyphen - is used to promote reading.

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