Tool for decoding or encoding with Base 92. Base 92 code allows binary information to be stored in ASCII format with minimal data loss.
Base 92 Encoding - dCode
Tag(s) : Character Encoding
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Base 92 Encoding
Base 92 Decoder
Base 92 Encoder
Answers to Questions (FAQ)
What is Base 92? (Definition)
What characters are used in Base 92?
The 92 character alphabet used in Base 92 is indexed as follows:
| (empty) | ~ | 9 | + | 19 | 5 | 29 | ? | 39 | I | 49 | S | 59 | ] | 69 | h | 79 | r | 89 | | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | ! | 10 | , | 20 | 6 | 30 | @ | 40 | J | 50 | T | 60 | ^ | 70 | i | 80 | s | 90 | } |
| 1 | # | 11 | - | 21 | 7 | 31 | A | 41 | K | 51 | U | 61 | _ | 71 | j | 81 | t | ||
| 2 | $ | 12 | . | 22 | 8 | 32 | B | 42 | L | 52 | V | 62 | a | 72 | k | 82 | u | ||
| 3 | % | 13 | / | 23 | 9 | 33 | C | 43 | M | 53 | W | 63 | b | 73 | l | 83 | v | ||
| 4 | & | 14 | 0 | 24 | : | 34 | D | 44 | N | 54 | X | 64 | c | 74 | m | 84 | w | ||
| 5 | ' | 15 | 1 | 25 | ; | 35 | E | 45 | O | 55 | Y | 65 | d | 75 | n | 85 | x | ||
| 6 | ( | 16 | 2 | 26 | < | 36 | F | 46 | P | 56 | Z | 66 | e | 76 | o | 86 | y | ||
| 7 | ) | 17 | 3 | 27 | = | 37 | G | 47 | Q | 57 | [ | 67 | f | 77 | p | 87 | z | ||
| 8 | * | 18 | 4 | 28 | > | 38 | H | 48 | R | 58 | \ | 68 | g | 78 | q | 88 | { |
In practice, only 91 signs are used in basic calculations, the 92nd (the tilde ~) is only used to indicate an empty string.
How to encode data in Base 92?
To encode data in Base 92, cut the data into 13-bit blocks to make 2 base 91 characters (yes 91 and not 92).
Example: dCode is written in binary (ASCII) 0110010001000011011011110110010001100101
Blocking of 13 bits gives 0110010001000,0110110111101,1001000110010,1
The converting 0110010001000 (base 2) gives ' 3208' (base 10) or 35×91+23. Character 35 of base 91 is E and character 23 is 9 whose block is coded E9.
Complete the last block with 0 on the right. Pad to 6 bits if the block contained 6 bits or less, otherwise pad to 13 bits.
Example: The last block 1 (length 1 bit) is completed to 100000 (completed over 6 bits) or 32 in base 10, and symbol 32 is B.
The complete coded message is E9H]U3B
How to decode Base 92?
For each pair of characters, note the value of each symbol in the Base 92 alphabet. Multiply the first by 91 and add them.
Example: Decode 9A2?VBWl by splitting it into pairs 9A 2? VB Wl. The first character 9 has the index 23, and A the code 31. The calculation is 23×91+31=2124.
For each number obtained, convert it to binary, completing it if necessary on the left to obtain 13 bits.
Example: 2124 in base 10 corresponds to 100001001100 in binary, as this number is only 12 bits, add an initial zero or 0100001001100
The binary sequence obtained (by concatenation of 13-bit numbers) corresponds to the plain message. If the message was originally encoded in 8-bit ASCII, then each byte corresponds to an ASCII character.
Example: The binary sequence is 01000010,01100001,01110011,01100101,00111001,00110010 or the 6 Base92 characters
How to recognize a Base 92 ciphertext? (Identification)
The message is composed of the 91 characters of the Base92 alphabet.
The character ~ appears alone or does not appear.
If the message length is odd, then the last character can only be among the first 64 characters of the alphabet.
Why use base 91?
Each 13-bit block can encode 2^13 = 8192 values, while 2 base 91 characters encode 91^2=8281 values. The encoding loss is therefore minimized for an alphabet of 91 symbols.
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Base 92 Encoding on dCode.fr [online website], retrieved on 2024-05-02,
